--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/ED/json-ld-syntax/20120930/diff-20120830.html Sat Sep 29 20:47:10 2012 -0400
@@ -0,0 +1,18797 @@
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+<head>
+<title>JSON-LD Syntax 1.0</title>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
+
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+<!--[if lt IE 9]><script src='undefined://www.w3.org/2008/site/js/html5shiv.js'></script><![endif]-->
+<style type='text/css'>
+.diff-old-a {
+ font-size: smaller;
+ color: red;
+}
+
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+ { content: "\2193" }
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+</head>
+
+
+<body>
+<div class="head">
+<p>
+<a href="http://www.w3.org/">
+<img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" />
+</a>
+</p>
+<h1 class="title" id="title">
+JSON-LD
+Syntax
+1.0
+</h1>
+<h2 id="subtitle">
+A
+Context-based
+JSON
+Serialization
+for
+Linking
+Data
+</h2>
+<h2 id="w3c-editor-s-draft-30-september-2012">
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+Editor's
+Draft
+30
+<del class="diff-old">August
+</del>
+<ins class="diff-chg">September
+</ins>
+2012
+</h2>
+<dl>
+<dt>
+This
+version:
+</dt>
+<dd>
+<del class="diff-old">http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/ED/json-ld-syntax/20120830/index.html
+</del>
+<a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html">
+<ins class="diff-chg">http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html
+</ins>
+</a>
+</dd>
+<dt>
+Latest
+published
+version:
+</dt>
+<dd>
+<a href="http://www.w3.org/TR/json-ld-syntax/">
+http://www.w3.org/TR/json-ld-syntax/
+</a>
+</dd>
+<dt>
+Latest
+editor's
+draft:
+</dt>
+<dd>
+<a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html">
+http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html
+</a>
+</dd>
+<dt>
+Editors:
+</dt>
+<dd rel="bibo:editor" inlist="">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://manu.sporny.org/">
+Manu
+Sporny
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</span>
+</dd>
+<dd rel="bibo:editor" inlist="">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
+Gregg
+Kellogg
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
+Kellogg
+Associates
+</a>
+</span>
+</dd>
+<dd rel="bibo:editor" inlist="">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
+Markus
+Lanthaler
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
+Graz
+University
+of
+Technology
+</a>
+</span>
+</dd>
+<dt>
+Authors:
+</dt>
+<dd rel="dcterms:contributor">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://digitalbazaar.com/">
+Manu
+Sporny
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</span>
+</dd>
+<dd rel="dcterms:contributor">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">
+Dave
+Longley
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</span>
+</dd>
+<dd rel="dcterms:contributor">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">
+Gregg
+Kellogg
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">
+Kellogg
+Associates
+</a>
+</span>
+</dd>
+<dd rel="dcterms:contributor">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">
+Markus
+Lanthaler
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">
+Graz
+University
+of
+Technology
+</a>
+</span>
+</dd>
+<dd rel="dcterms:contributor">
+<span typeof="foaf:Person">
+<a rel="foaf:homepage" property="foaf:name" content="Mark Birbeck" href="http://webbackplane.com/">
+Mark
+Birbeck
+</a>,
+<a rel="foaf:workplaceHomepage" href="http://webbackplane.com/">
+Backplane
+Ltd.
+</a>
+</span>
+</dd>
+</dl>
+<p>
+This
+document
+is
+also
+available
+in
+this
+non-normative
+format:
+<a href="diff-20120830.html">
+diff
+to
+previous
+version
+</a>
+</p>
+<p class="copyright">
+<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">
+Copyright
+</a>
+©
+2010-2012
+<a href="http://www.w3.org/">
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+</a>
+<sup>
+®
+</sup>
+(
+<a href="http://www.csail.mit.edu/">
+<abbr title="Massachusetts Institute of Technology">
+MIT
+</abbr>
+</a>,
+<a href="http://www.ercim.eu/">
+<abbr title="European Research Consortium for Informatics and Mathematics">
+ERCIM
+</abbr>
+</a>,
+<a href="http://www.keio.ac.jp/">
+Keio
+</a>
+),
+All
+Rights
+Reserved.
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+<a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">
+liability
+</a>,
+<a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">
+trademark
+</a>
+and
+<a href="http://www.w3.org/Consortium/Legal/copyright-documents">
+document
+use
+</a>
+rules
+apply.
+</p>
+<hr />
+</div>
+<section id="abstract" class="introductory">
+<h2>
+Abstract
+</h2>
+<p>
+JSON
+has
+proven
+to
+be
+a
+highly
+useful
+object
+serialization
+and
+messaging
+format.
+In
+an
+attempt
+to
+harmonize
+the
+representation
+of
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+in
+JSON,
+this
+specification
+outlines
+a
+common
+JSON
+representation
+format
+for
+expressing
+directed
+graphs;
+mixing
+both
+Linked
+Data
+and
+non-Linked
+Data
+in
+a
+single
+document.
+</p>
+</section>
+<section id="sotd" class="introductory">
+<h2>
+Status
+of
+This
+Document
+</h2>
+<p>
+<em>
+This
+section
+describes
+the
+status
+of
+this
+document
+at
+the
+time
+of
+its
+publication.
+Other
+documents
+may
+supersede
+this
+document.
+A
+list
+of
+current
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+publications
+and
+the
+latest
+revision
+of
+this
+technical
+report
+can
+be
+found
+in
+the
+<a href="http://www.w3.org/TR/">
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+technical
+reports
+index
+</a>
+at
+http://www.w3.org/TR/.
+</em>
+</p>
+<p>
+This
+document
+has
+been
+under
+development
+for
+over
+<del class="diff-old">18
+</del>
+<ins class="diff-chg">20
+</ins>
+months
+in
+the
+JSON
+for
+Linking
+Data
+Community
+Group.
+The
+document
+has
+recently
+been
+transferred
+to
+the
+RDF
+Working
+Group
+for
+review,
+improvement,
+and
+publication
+along
+the
+Recommendation
+track.
+The
+specification
+has
+undergone
+significant
+development,
+review,
+and
+changes
+during
+the
+course
+of
+the
+last
+<del class="diff-old">18
+</del>
+<ins class="diff-chg">20
+</ins>
+months.
+</p>
+<p>
+There
+are
+currently
+<a href="http://json-ld.org/#impl">
+five
+interoperable
+implementations
+</a>
+of
+this
+specification.
+There
+is
+a
+<a href="https://github.com/json-ld/json-ld.org/tree/master/test-suite">
+fairly
+complete
+test
+suite
+</a>
+and
+a
+<a href="http://json-ld.org/playground/">
+live
+JSON-LD
+editor
+</a>
+that
+is
+capable
+of
+demonstrating
+the
+features
+described
+in
+this
+document.
+While
+development
+on
+implementations,
+the
+test
+suite
+and
+the
+live
+editor
+will
+continue,
+they
+are
+believed
+to
+be
+mature
+enough
+to
+be
+integrated
+into
+a
+non-production
+system
+at
+this
+point
+in
+time
+with
+the
+expectation
+that
+they
+could
+be
+used
+in
+a
+production
+system
+within
+the
+next
+year.
+</p>
+<p>
+There
+are
+a
+number
+of
+ways
+that
+one
+may
+participate
+in
+the
+development
+of
+this
+specification:
+</p>
+<ul>
+<li>
+If
+you
+want
+to
+make
+sure
+that
+your
+feedback
+is
+formally
+addressed
+by
+the
+RDF
+Working
+Group,
+you
+should
+send
+it
+to
+public-rdf-comments:
+<a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">
+public-rdf-comments@w3.org
+</a>
+</li>
+<li>
+Ad-hoc
+technical
+discussion
+primarily
+occurs
+on
+the
+public
+community
+mailing
+list:
+<a href="http://lists.w3.org/Archives/Public/public-linked-json/">
+public-linked-json@w3.org
+</a>
+</li>
+<li>
+<a href="http://json-ld.org/minutes/">
+Public
+JSON-LD
+Community
+Group
+teleconferences
+</a>
+are
+held
+on
+Tuesdays
+at
+1500UTC
+every
+week.
+</li>
+<li>
+RDF
+Working
+Group
+teleconferences
+are
+held
+on
+Wednesdays
+at
+1500UTC
+every
+week.
+Participation
+is
+limited
+to
+RDF
+Working
+Group
+members.
+</li>
+<li>
+Specification
+bugs
+and
+issues
+should
+be
+reported
+in
+the
+<a href="https://github.com/json-ld/json-ld.org/issues">
+issue
+tracker
+</a>
+if
+you
+do
+not
+want
+to
+send
+an
+e-mail
+to
+the
+public-rdf-comments
+mailing
+list.
+</li>
+<li>
+<a href="https://github.com/json-ld/json-ld.org/tree/master/spec">
+Source
+code
+</a>
+for
+the
+specification
+can
+be
+found
+on
+Github.
+</li>
+<li>
+The
+<a href="http://webchat.freenode.net/?channels=json-ld">
+#json-ld
+</a>
+IRC
+channel
+is
+available
+for
+real-time
+discussion
+on
+irc.freenode.net.
+</li>
+</ul>
+<p>
+This
+document
+was
+published
+by
+the
+<a href="http://www.w3.org/2011/rdf-wg/">
+RDF
+Working
+Group
+</a>
+as
+an
+Editor's
+Draft.
+If
+you
+wish
+to
+make
+comments
+regarding
+this
+document,
+please
+send
+them
+to
+<a href="mailto:public-rdf-comments@w3.org">
+public-rdf-comments@w3.org
+</a>
+(
+<a href="mailto:public-rdf-comments-request@w3.org?subject=subscribe">
+subscribe
+</a>,
+<a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">
+archives
+</a>
+).
+All
+feedback
+is
+welcome.
+</p>
+<p>
+Publication
+as
+an
+Editor's
+Draft
+does
+not
+imply
+endorsement
+by
+the
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+Membership.
+This
+is
+a
+draft
+document
+and
+may
+be
+updated,
+replaced
+or
+obsoleted
+by
+other
+documents
+at
+any
+time.
+It
+is
+inappropriate
+to
+cite
+this
+document
+as
+other
+than
+work
+in
+progress.
+</p>
+<p>
+This
+document
+was
+produced
+by
+a
+group
+operating
+under
+the
+<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">
+5
+February
+2004
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+Patent
+Policy
+</a>.
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+maintains
+a
+<a href="http://www.w3.org/2004/01/pp-impl/46168/status" rel="disclosure">
+public
+list
+of
+any
+patent
+disclosures
+</a>
+made
+in
+connection
+with
+the
+deliverables
+of
+the
+group;
+that
+page
+also
+includes
+instructions
+for
+disclosing
+a
+patent.
+An
+individual
+who
+has
+actual
+knowledge
+of
+a
+patent
+which
+the
+individual
+believes
+contains
+<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">
+Essential
+Claim(s)
+</a>
+must
+disclose
+the
+information
+in
+accordance
+with
+<a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">
+section
+6
+of
+the
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+Patent
+Policy
+</a>.
+</p>
+</section>
+<section id="toc">
+<h2 class="introductory">
+Table
+of
+Contents
+</h2>
+<ul class="toc">
+<li class="tocline">
+<a href="#introduction" class="tocxref">
+<span class="secno">
+1.
+</span>
+Introduction
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#how-to-read-this-document" class="tocxref">
+<span class="secno">
+1.1
+</span>
+How
+to
+Read
+this
+Document
+</a>
+</li>
+<del class="diff-old">1.2
+General
+Terminology
+</del>
+</ul>
+</li>
+<li class="tocline">
+<a href="#design-goals-and-rationale" class="tocxref">
+<span class="secno">
+2.
+</span>
+Design
+Goals
+and
+Rationale
+</a>
+</li>
+<li class="tocline">
+<a href="#basic-concepts" class="tocxref">
+<span class="secno">
+3.
+</span>
+Basic
+Concepts
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#benefits-of-json-ld" class="tocxref">
+<span class="secno">
+3.1
+</span>
+<del class="diff-old">Linked
+</del>
+<ins class="diff-chg">Benefits
+of
+JSON-LD
+</ins></a></li><li class="tocline"><a href="#json-ld-data-model" class="tocxref"><span class="secno"><ins class="diff-chg">
+3.2
+</ins></span><ins class="diff-chg">
+JSON-LD
+</ins>
+Data
+<ins class="diff-new">Model
+</ins></a></li><li class="tocline"><a href="#general-terminology" class="tocxref"><span class="secno"><ins class="diff-new">
+3.3
+</ins></span><ins class="diff-new">
+General
+Terminology
+</ins>
+</a>
+</li>
+<li class="tocline">
+<a href="#syntax-tokens-and-keywords" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.2
+</del>
+<ins class="diff-chg">3.4
+</ins>
+</span>
+Syntax
+Tokens
+and
+Keywords
+</a>
+</li>
+<li class="tocline">
+<a href="#the-context" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.3
+</del>
+<ins class="diff-chg">3.5
+</ins>
+</span>
+The
+Context
+</a>
+</li>
+<li class="tocline">
+<a href="#from-json-to-json-ld" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.4
+</del>
+<ins class="diff-chg">3.6
+</ins>
+</span>
+From
+JSON
+to
+JSON-LD
+</a>
+</li>
+<li class="tocline">
+<a href="#iris" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.5
+</del>
+<ins class="diff-chg">3.7
+</ins>
+</span>
+IRIs
+</a>
+</li>
+<li class="tocline">
+<a href="#node-identifiers" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.6
+</del>
+<ins class="diff-chg">3.8
+</ins>
+</span>
+Node
+Identifiers
+</a>
+</li>
+<li class="tocline">
+<a href="#specifying-the-type" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.7
+</del>
+<ins class="diff-chg">3.9
+</ins>
+</span>
+Specifying
+the
+Type
+</a>
+</li>
+<li class="tocline">
+<a href="#string-internationalization" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.8
+</del>
+<ins class="diff-chg">3.10
+</ins>
+</span>
+String
+Internationalization
+</a>
+</li>
+<li class="tocline">
+<a href="#json-ld-syntax" class="tocxref">
+<span class="secno">
+<del class="diff-old">3.9
+</del>
+<ins class="diff-chg">3.11
+</ins>
+</span>
+JSON-LD
+Syntax
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#advanced-concepts" class="tocxref">
+<span class="secno">
+4.
+</span>
+Advanced
+Concepts
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#compact-iris" class="tocxref">
+<span class="secno">
+4.1
+</span>
+Compact
+IRIs
+</a>
+</li>
+<li class="tocline">
+<a href="#typed-values" class="tocxref">
+<span class="secno">
+4.2
+</span>
+Typed
+Values
+</a>
+</li>
+<li class="tocline">
+<a href="#language-tagged-strings" class="tocxref">
+<span class="secno">
+4.3
+</span>
+Language-tagged
+Strings
+</a>
+</li>
+<li class="tocline">
+<a href="#referencing-contexts-from-json-documents" class="tocxref">
+<span class="secno">
+4.4
+</span>
+Referencing
+Contexts
+from
+JSON
+Documents
+</a>
+</li>
+<li class="tocline">
+<a href="#expanded-term-definition" class="tocxref">
+<span class="secno">
+4.5
+</span>
+Expanded
+Term
+Definition
+</a>
+</li>
+<li class="tocline">
+<a href="#type-coercion" class="tocxref">
+<span class="secno">
+4.6
+</span>
+Type
+Coercion
+</a>
+</li>
+<li class="tocline">
+<a href="#property-generators" class="tocxref">
+<span class="secno">
+4.7
+</span>
+Property
+Generators
+</a>
+</li>
+<li class="tocline">
+<a href="#iri-expansion-within-a-context" class="tocxref">
+<span class="secno">
+4.8
+</span>
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+Expansion
+Within
+a
+Context
+</a>
+</li>
+<li class="tocline">
+<a href="#sets-and-lists" class="tocxref">
+<span class="secno">
+4.9
+</span>
+Sets
+and
+Lists
+</a>
+</li>
+<li class="tocline">
+<a href="#embedding" class="tocxref">
+<span class="secno">
+4.10
+</span>
+Embedding
+</a>
+</li>
+<li class="tocline">
+<a href="#named-graphs" class="tocxref">
+<span class="secno">
+4.11
+</span>
+Named
+Graphs
+</a>
+</li>
+<li class="tocline">
+<a href="#identifying-unlabeled-nodes" class="tocxref">
+<span class="secno">
+4.12
+</span>
+Identifying
+Unlabeled
+Nodes
+</a>
+</li>
+<li class="tocline">
+<a href="#aliasing-keywords" class="tocxref">
+<span class="secno">
+4.13
+</span>
+Aliasing
+Keywords
+</a>
+</li>
+<li class="tocline">
+<a href="#expanded-document-form" class="tocxref">
+<span class="secno">
+4.14
+</span>
+Expanded
+Document
+Form
+</a>
+</li>
+<li class="tocline">
+<a href="#compact-document-form" class="tocxref">
+<span class="secno">
+4.15
+</span>
+Compact
+Document
+Form
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#json-ld-grammar" class="tocxref">
+<span class="secno">
+A.
+</span>
+JSON-LD
+Grammar
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#grammar-node-definition" class="tocxref">
+<span class="secno">
+A.1
+</span>
+Node
+Definition
+</a>
+</li>
+<li class="tocline">
+<a href="#grammar-node-reference" class="tocxref">
+<span class="secno">
+A.2
+</span>
+Node
+Reference
+</a>
+</li>
+<li class="tocline">
+<a href="#grammar-language-map" class="tocxref">
+<span class="secno">
+A.3
+</span>
+Language
+Map
+</a>
+</li>
+<li class="tocline">
+<a href="#grammar-expanded-values" class="tocxref">
+<span class="secno">
+A.4
+</span>
+Expanded
+Values
+</a>
+</li>
+<li class="tocline">
+<a href="#grammar-set-list" class="tocxref">
+<span class="secno">
+A.5
+</span>
+List
+and
+Set
+Values
+</a>
+</li>
+<li class="tocline">
+<a href="#grammar-context" class="tocxref">
+<span class="secno">
+A.6
+</span>
+Context
+Definition
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#relationship-to-other-linked-data-formats-and-data-models" class="tocxref">
+<span class="secno">
+B.
+</span>
+Relationship
+to
+Other
+Linked
+Data
+Formats
+and
+Data
+Models
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#rdf" class="tocxref">
+<span class="secno">
+B.1
+</span>
+RDF
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#turtle" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.2
+</del>
+<ins class="diff-chg">B.1.1
+</ins>
+</span>
+Turtle
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#prefix-definitions" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.2.1
+</del>
+<ins class="diff-chg">B.1.1.1
+</ins>
+</span>
+Prefix
+definitions
+</a>
+</li>
+<li class="tocline">
+<a href="#embedding-1" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.2.2
+</del>
+<ins class="diff-chg">B.1.1.2
+</ins>
+</span>
+Embedding
+</a>
+</li>
+<li class="tocline">
+<a href="#lists" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.2.3
+</del>
+<ins class="diff-chg">B.1.1.3
+</ins>
+</span>
+Lists
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#rdfa" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.3
+</del>
+<ins class="diff-chg">B.1.2
+</ins>
+</span>
+RDFa
+</a>
+</li>
+<li class="tocline">
+<a href="#microformats" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.4
+</del>
+<ins class="diff-chg">B.1.3
+</ins>
+</span>
+Microformats
+</a>
+</li>
+<li class="tocline">
+<a href="#microdata" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.5
+</del>
+<ins class="diff-chg">B.1.4
+</ins>
+</span>
+Microdata
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#iana-considerations" class="tocxref">
+<span class="secno">
+<del class="diff-old">C.
+</del>
+<ins class="diff-chg">B.2
+</ins>
+</span>
+IANA
+Considerations
+</a>
+</li>
+<li class="tocline">
+<a href="#acknowledgements" class="tocxref">
+<span class="secno">
+<del class="diff-old">D.
+</del>
+<ins class="diff-chg">B.3
+</ins>
+</span>
+Acknowledgements
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#references" class="tocxref">
+<span class="secno">
+<del class="diff-old">E.
+</del>
+<ins class="diff-chg">C.
+</ins>
+</span>
+References
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#normative-references" class="tocxref">
+<span class="secno">
+<del class="diff-old">E.1
+</del>
+<ins class="diff-chg">C.1
+</ins>
+</span>
+Normative
+references
+</a>
+</li>
+<li class="tocline">
+<a href="#informative-references" class="tocxref">
+<span class="secno">
+<del class="diff-old">E.2
+</del>
+<ins class="diff-chg">C.2
+</ins>
+</span>
+Informative
+references
+</a>
+</li>
+</ul>
+</li>
+</ul>
+</section>
+<section class="informative" id="introduction">
+<h2>
+<span class="secno">
+1.
+</span>
+Introduction
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+JSON,
+as
+specified
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+],
+is
+a
+simple
+language
+for
+representing
+data
+on
+the
+Web.
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+is
+a
+technique
+for
+creating
+a
+network
+of
+inter-connected
+data
+across
+different
+Web
+documents
+and
+Web
+sites.
+A
+<em>
+document
+</em>
+in
+this
+data
+network
+is
+typically
+identified
+using
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(Internationalized
+Resource
+Identifier).
+A
+software
+program
+can
+typically
+follow
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+just
+like
+you
+follow
+a
+URL
+by
+putting
+it
+into
+your
+browser's
+location
+bar.
+By
+following
+IRIs,
+a
+software
+program
+can
+find
+more
+information
+about
+the
+<em>
+document
+</em>
+and
+the
+<em>
+thing
+</em>
+s
+that
+the
+document
+describes.
+These
+<em>
+things
+</em>
+may
+also
+be
+identified
+using
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s.
+The
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+allows
+a
+software
+program
+to
+start
+at
+one
+<em>
+document
+</em>
+and
+follow
+links
+to
+other
+<em>
+documents
+</em>
+or
+<em>
+things
+</em>
+in
+order
+to
+learn
+more
+about
+all
+of
+the
+<em>
+documents
+</em>
+and
+<em>
+things
+</em>
+described
+on
+the
+Web.
+</p>
+<p>
+JSON-LD
+is
+designed
+as
+a
+lightweight
+syntax
+that
+can
+be
+used
+to
+express
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>.
+It
+is
+primarily
+intended
+to
+be
+a
+way
+to
+use
+Linked
+Data
+in
+Javascript
+and
+other
+Web-based
+programming
+environments.
+It
+is
+also
+useful
+when
+building
+inter-operable
+Web
+services
+and
+when
+storing
+Linked
+Data
+in
+JSON-based
+document
+storage
+engines.
+It
+is
+practical
+and
+designed
+to
+be
+as
+simple
+as
+possible,
+utilizing
+the
+large
+number
+of
+JSON
+parsers
+and
+libraries
+available
+today.
+</p>
+<p>
+The
+syntax
+does
+not
+necessarily
+require
+applications
+to
+change
+their
+JSON,
+but
+allows
+one
+to
+easily
+add
+meaning
+by
+simply
+adding
+or
+referencing
+a
+context.
+The
+syntax
+is
+designed
+to
+not
+disturb
+already
+deployed
+systems
+running
+on
+JSON,
+but
+provide
+a
+smooth
+upgrade
+path
+from
+JSON
+to
+JSON-LD.
+Finally,
+the
+format
+is
+intended
+to
+be
+easy
+to
+parse,
+efficient
+to
+generate,
+and
+<del class="diff-old">only
+requires
+a
+</del>
+<ins class="diff-chg">can
+operate
+inside
+of
+devices
+that
+contain
+</ins>
+very
+<del class="diff-old">small
+memory
+footprint
+in
+order
+to
+operate.
+</del>
+<ins class="diff-chg">little
+memory.
+</ins>
+</p>
+<section id="how-to-read-this-document">
+<h3>
+<span class="secno">
+1.1
+</span>
+How
+to
+Read
+this
+Document
+</h3>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+This
+document
+is
+a
+detailed
+specification
+for
+a
+serialization
+of
+Linked
+Data
+in
+JSON.
+The
+document
+is
+primarily
+intended
+for
+the
+following
+audiences:
+</p>
+<ul>
+<li>
+Software
+developers
+that
+want
+to
+encode
+Linked
+Data
+in
+a
+<del class="diff-old">way
+</del>
+<ins class="diff-chg">variety
+of
+programing
+languages
+</ins>
+that
+<del class="diff-old">is
+cross-language
+compatible
+via
+</del>
+<ins class="diff-chg">can
+use
+</ins>
+JSON.
+</li>
+<li>
+Software
+developers
+that
+want
+to
+understand
+the
+design
+decisions
+and
+language
+syntax
+for
+JSON-LD.
+</li>
+<li>
+Software
+developers
+that
+want
+to
+implement
+processors
+and
+APIs
+for
+JSON-LD.
+</li>
+</ul>
+<p>
+This
+specification
+does
+not
+describe
+the
+programming
+interfaces
+for
+the
+JSON-LD
+Syntax.
+The
+specification
+that
+describes
+the
+programming
+interfaces
+for
+JSON-LD
+documents
+is
+the
+JSON-LD
+Application
+Programming
+Interface
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+</p>
+<p>
+To
+understand
+the
+basics
+in
+this
+specification
+you
+must
+first
+be
+familiar
+with
+JSON,
+which
+is
+detailed
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+].
+</p>
+</section>
+<del class="diff-old">1.2
+General
+Terminology
+The
+following
+is
+an
+explanation
+of
+the
+general
+terminology
+used
+in
+this
+document:
+JSON
+object
+An
+object
+structure
+is
+represented
+as
+a
+pair
+of
+curly
+brackets
+surrounding
+zero
+or
+more
+name-value
+pairs.
+A
+name
+is
+a
+string
+.
+A
+single
+colon
+comes
+after
+each
+name,
+separating
+the
+name
+from
+the
+value.
+A
+single
+comma
+separates
+a
+value
+from
+a
+following
+name.
+The
+names
+within
+an
+object
+should
+be
+unique.
+array
+In
+JSON,
+an
+array
+is
+an
+ordered
+sequence
+of
+zero
+or
+more
+values.
+An
+array
+is
+represented
+as
+square
+brackets
+surrounding
+zero
+or
+more
+values
+that
+are
+separated
+by
+commas.
+While
+JSON-LD
+uses
+the
+same
+array
+representation
+as
+JSON,
+the
+collection
+is
+unordered
+by
+default.
+While
+order
+is
+preserved
+in
+regular
+JSON
+arrays,
+it
+is
+not
+in
+regular
+JSON-LD
+arrays
+unless
+specific
+markup
+is
+provided
+(see
+4.9
+Sets
+and
+Lists
+).
+string
+A
+string
+is
+a
+sequence
+of
+zero
+or
+more
+Unicode
+characters,
+wrapped
+in
+double
+quotes,
+using
+backslash
+escapes
+(if
+necessary).
+A
+character
+is
+represented
+as
+a
+single
+character
+string.
+number
+A
+number
+is
+similar
+to
+that
+used
+in
+most
+programming
+languages,
+except
+that
+the
+octal
+and
+hexadecimal
+formats
+are
+not
+used
+and
+that
+leading
+zeros
+are
+not
+allowed.
+true
+and
+false
+Values
+that
+are
+used
+to
+express
+one
+of
+two
+possible
+boolean
+states.
+null
+The
+null
+value
+is
+used
+to
+make
+the
+JSON-LD
+processor
+"forget"
+any
+previously
+defined
+JSON
+key
+that
+is
+associated
+with
+the
+null
+value.
+If
+a
+previous
+definition
+doesn't
+exist,
+the
+entire
+key-value
+is
+ignored.
+If
+a
+previous
+definition
+of
+the
+key
+does
+exist,
+the
+previous
+definition
+is
+undefined.
+node
+definition
+A
+JSON
+object
+used
+to
+represent
+a
+node
+and
+one
+or
+more
+properties
+of
+that
+node.
+A
+JSON
+object
+is
+a
+node
+definition
+if
+it
+does
+not
+contain
+they
+keys
+@value
+,
+@list
+or
+@set
+and
+it
+has
+one
+or
+more
+keys
+other
+than
+@id
+.
+A
+node
+definition
+may
+be
+spread
+among
+different
+parts
+of
+a
+document
+or
+even
+between
+different
+documents.
+node
+reference
+A
+JSON
+object
+used
+to
+reference
+a
+node
+having
+only
+the
+@id
+key.
+</del>
+</section>
+<section class="informative" id="design-goals-and-rationale">
+<h2>
+<span class="secno">
+2.
+</span>
+Design
+Goals
+and
+Rationale
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+A
+number
+of
+design
+goals
+were
+established
+before
+the
+creation
+of
+this
+markup
+language:
+</p>
+<dl>
+<dt>
+Simplicity
+</dt>
+<dd>
+No
+extra
+processors
+or
+software
+libraries
+should
+be
+necessary
+to
+use
+JSON-LD
+in
+its
+most
+basic
+form.
+The
+language
+will
+provide
+developers
+with
+a
+very
+easy
+learning
+curve.
+Developers
+need
+only
+know
+JSON
+and
+two
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>
+(
+<code>
+@context
+</code>
+and
+<code>
+@id
+</code>
+)
+to
+use
+the
+basic
+functionality
+in
+JSON-LD.
+</dd>
+<dt>
+Compatibility
+</dt>
+<dd>
+The
+JSON-LD
+markup
+must
+be
+100%
+compatible
+with
+JSON.
+This
+ensures
+that
+all
+of
+the
+standard
+JSON
+libraries
+work
+seamlessly
+with
+JSON-LD
+documents.
+</dd>
+<dt>
+Expressiveness
+</dt>
+<dd>
+The
+syntax
+must
+be
+able
+to
+express
+directed
+graphs,
+which
+have
+been
+proven
+to
+be
+able
+to
+express
+almost
+every
+real
+world
+data
+model.
+</dd>
+<dt>
+Terseness
+</dt>
+<dd>
+The
+JSON-LD
+syntax
+must
+be
+very
+terse
+and
+human
+readable,
+requiring
+as
+little
+effort
+as
+possible
+from
+the
+developer.
+</dd>
+<dt>
+Zero
+Edits,
+most
+of
+the
+time
+</dt>
+<dd>
+JSON-LD
+must
+provide
+a
+<a href="#referencing-contexts-from-json-documents">
+mechanism
+</a>
+that
+allows
+developers
+to
+specify
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+in
+a
+way
+that
+is
+out-of-band.
+This
+allows
+organizations
+that
+have
+already
+deployed
+large
+JSON-based
+infrastructure
+to
+add
+meaning
+to
+their
+JSON
+documents
+in
+a
+way
+that
+is
+not
+disruptive
+to
+their
+day-to-day
+operations
+and
+is
+transparent
+to
+their
+current
+customers.
+At
+times,
+mapping
+JSON
+to
+a
+graph
+representation
+can
+become
+difficult.
+In
+these
+instances,
+rather
+than
+having
+JSON-LD
+support
+an
+esoteric
+use
+case,
+we
+chose
+not
+to
+support
+the
+use
+case
+and
+support
+a
+simplified
+syntax
+instead.
+So,
+while
+Zero
+Edits
+is
+a
+design
+goal,
+it
+is
+not
+always
+possible
+without
+adding
+great
+complexity
+to
+the
+language.
+</dd>
+<dt>
+One-pass
+Processing
+</dt>
+<dd>
+JSON-LD
+supports
+one-pass
+processing,
+which
+results
+in
+a
+very
+small
+memory
+footprint
+when
+processing
+documents.
+For
+example,
+to
+expand
+a
+JSON-LD
+document
+from
+a
+compacted
+form,
+only
+one
+pass
+is
+required
+over
+the
+data.
+</dd>
+<dt>
+Linked
+Data-centric
+</dt>
+<dd>
+The
+focus
+on
+Linked
+Data
+is
+placed
+at
+a
+much
+higher
+priority
+than
+the
+focus
+on
+the
+Semantic
+Web.
+One
+outcome
+of
+this
+ordering
+of
+priorities
+is
+an
+aggressively
+reduced
+focus
+on
+the
+Semantic
+Web
+stack
+(RDF
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+],
+TURTLE
+[
+<cite>
+<a class="bibref" href="#bib-TURTLE-TR">
+TURTLE-TR
+</a>
+</cite>
+],
+triple
+stores,
+and
+SPARQL
+[
+<cite>
+<a class="bibref" href="#bib-RDF-SPARQL-QUERY">
+RDF-SPARQL-QUERY
+</a>
+</cite>
+]).
+While
+this
+may
+be
+off-putting
+to
+proponents
+of
+the
+Semantic
+Web,
+the
+audience
+for
+this
+specification
+are
+Web
+developers
+that
+want
+a
+gentler
+introduction
+and
+a
+simpler
+technology
+stack
+for
+using
+Linked
+Data
+in
+their
+Web
+applications.
+Semantic
+Web
+concepts,
+such
+as
+conversion
+to
+and
+from
+RDF,
+are
+fully
+supported
+by
+JSON-LD,
+but
+the
+implementation
+of
+these
+features
+are
+not
+elaborated
+upon
+in
+this
+specification.
+See
+<a href="#relationship-to-other-linked-data-formats-and-data-models" class="sec-ref">
+<span class="secno">
+B.
+</span>
+<span class="sec-title">
+Relationship
+to
+Other
+Linked
+Data
+Formats
+and
+Data
+Models
+</span>
+</a>
+for
+more
+information
+about
+how
+JSON-LD
+integrates
+into
+the
+more
+traditional
+Semantic
+Web
+stack.
+</dd>
+</dl>
+</section>
+<section class="normative" id="basic-concepts">
+<h2>
+<span class="secno">
+3.
+</span>
+Basic
+Concepts
+</h2>
+<em>
+This
+section
+is
+normative.
+</em>
+<p>
+JSON-LD
+is
+designed
+to
+ensure
+that
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+concepts
+can
+be
+marked
+up
+in
+a
+way
+that
+is
+simple
+to
+understand
+and
+create
+by
+Web
+authors.
+In
+many
+cases,
+regular
+JSON
+markup
+can
+become
+Linked
+Data
+with
+the
+simple
+addition
+of
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+As
+more
+JSON-LD
+features
+are
+used,
+more
+semantics
+are
+added
+to
+the
+JSON
+markup.
+</p>
+<section id="benefits-of-json-ld">
+<h3>
+<span class="secno">
+3.1
+</span>
+<del class="diff-old">Linked
+Data
+</del>
+<ins class="diff-chg">Benefits
+of
+JSON-LD
+</ins>
+</h3>
+<p>
+<del class="diff-old">The
+following
+definition
+for
+Linked
+Data
+is
+the
+one
+</del>
+<ins class="diff-chg">JSON
+provides
+a
+number
+of
+benefits
+to
+software
+developers
+</ins>
+that
+<del class="diff-old">will
+be
+used
+for
+this
+specification.
+</del>
+<ins class="diff-chg">need
+to
+serialize
+data:
+</ins>
+</p>
+<ol>
+<li>
+<del class="diff-old">Linked
+Data
+</del>
+<ins class="diff-chg">It
+</ins>
+is
+<ins class="diff-new">easy
+for
+humans
+to
+read
+and
+write.
+</ins></li><li><ins class="diff-new">
+It
+is
+easy
+for
+machines
+to
+parse
+and
+generate.
+</ins></li><li><ins class="diff-new">
+It
+has
+</ins>
+a
+<del class="diff-old">set
+</del>
+<ins class="diff-chg">syntax
+that
+is
+familiar
+across
+a
+large
+number
+</ins>
+of
+<del class="diff-old">documents,
+each
+containing
+</del>
+<ins class="diff-chg">programming
+languages.
+</ins></li><li><ins class="diff-chg">
+It
+is
+capable
+of
+representing
+many
+different
+types
+of
+data
+using
+two
+universal
+data
+structures;
+</ins>
+a
+<del class="diff-old">representation
+</del>
+<ins class="diff-chg">collection
+</ins>
+of
+<ins class="diff-new">key-value
+pairs
+and
+lists.
+</ins></li></ol><p><ins class="diff-new">
+JSON
+has
+become
+</ins>
+a
+<del class="diff-old">linked
+</del>
+<ins class="diff-chg">very
+popular
+data-interchange
+format
+on
+the
+Web,
+particularly
+for
+</ins><a href="http://en.wikipedia.org/wiki/REST"><ins class="diff-chg">
+REST
+</ins></a><ins class="diff-chg">
+-based
+Web
+Services.
+Unfortunately,
+it
+has
+a
+number
+of
+short-comings
+that
+other
+Web-native
+</ins>
+data
+<del class="diff-old">graph
+.
+</del>
+<ins class="diff-chg">formats
+do
+not
+have:
+</ins></p><ol>
+<li>
+<del class="diff-old">A
+linked
+data
+graph
+</del>
+<ins class="diff-chg">There
+</ins>
+is
+<del class="diff-old">an
+unordered
+labeled
+directed
+graph,
+where
+nodes
+are
+IRIs
+</del>
+<ins class="diff-chg">no
+standardized,
+universal
+identifier
+mechanism
+for
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins>
+</a>
+<del class="diff-old">or
+Blank
+Nodes
+,
+or
+</del>
+<ins class="diff-chg">s.
+</ins></li><li><ins class="diff-chg">
+The
+meaning
+of
+the
+keys
+used
+in
+a
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></a><ins class="diff-chg">
+s
+are
+ambiguous
+and
+often
+conflict
+with
+</ins>
+other
+<del class="diff-old">values.
+</del>
+<ins class="diff-chg">data
+published
+on
+the
+Web.
+</ins>
+</li>
+<li>
+<del class="diff-old">A
+node
+</del>
+<ins class="diff-chg">There
+is
+no
+standardized
+way
+for
+a
+value
+in
+a
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins>
+</a>
+<del class="diff-old">having
+an
+outgoing
+edge
+must
+be
+an
+IRI
+</del>
+<ins class="diff-chg">to
+refer
+to
+a
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins>
+</a>
+<del class="diff-old">or
+Blank
+Node
+.
+</del>
+<ins class="diff-chg">on
+a
+different
+site
+on
+the
+Web.
+</ins>
+</li>
+<li>
+A
+<del class="diff-old">node
+</del>
+<ins class="diff-chg">developer
+cannot
+express
+the
+language
+associated
+with
+a
+</ins><a class="tref internalDFN" title="string" href="#dfn-string"><ins class="diff-chg">
+string
+</ins>
+</a>
+<del class="diff-old">having
+an
+incoming
+edge
+must
+be
+an
+IRI
+,
+Blank
+Node
+,
+or
+</del>
+value
+<del class="diff-old">such
+as
+</del>
+<ins class="diff-chg">in
+</ins>
+a
+<del class="diff-old">number
+or
+string.
+</del>
+<ins class="diff-chg">standardized
+manner.
+</ins>
+</li>
+<li>
+<del class="diff-old">A
+node
+may
+have
+both
+incoming
+</del>
+<ins class="diff-chg">There
+is
+no
+standard
+mechanism
+to
+associate
+datatypes
+with
+values
+such
+as
+dates,
+times,
+weights,
+</ins>
+and
+<del class="diff-old">outgoing
+edges.
+</del>
+<ins class="diff-chg">distances.
+</ins>
+</li>
+<li>
+<del class="diff-old">An
+edge
+must
+be
+labeled
+</del>
+<ins class="diff-chg">There
+is
+no
+facility
+to
+express
+a
+Web
+of
+information
+(directed
+graph),
+such
+as
+a
+social
+network,
+in
+a
+standardized
+manner.
+</ins></li></ol><p><ins class="diff-chg">
+JSON-LD
+is
+a
+web-native
+standard,
+is
+100%
+compatible
+</ins>
+with
+<del class="diff-old">an
+absolute
+</del>
+<ins class="diff-chg">JSON,
+provides
+all
+of
+the
+facilities
+that
+JSON
+provides,
+and
+extends
+the
+language
+to
+provide
+the
+following
+core
+advantages:
+</ins></p><ol><li><ins class="diff-chg">
+A
+universal
+identifier
+mechanism
+for
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></a><ins class="diff-chg">
+s
+via
+the
+use
+of
+</ins><a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<del class="diff-old">,
+within
+the
+JSON-LD
+syntax,
+this
+label
+is
+called
+a
+property
+.
+</del>
+</a>
+<ins class="diff-chg">s.
+</ins>
+</li>
+<li>
+<del class="diff-old">IRIs
+used
+within
+a
+linked
+data
+graph
+should
+be
+dereferenceable
+</del>
+<ins class="diff-chg">A
+way
+</ins>
+to
+<del class="diff-old">a
+Linked
+Data
+document
+describing
+</del>
+<ins class="diff-chg">dis-ambiguate
+</ins>
+the
+<del class="diff-old">resource
+denoted
+</del>
+<ins class="diff-chg">keys
+used
+between
+multiple
+JSON
+documents
+</ins>
+by
+<del class="diff-old">that
+</del>
+<ins class="diff-chg">mapping
+them
+to
+</ins>
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+<ins class="diff-new">s
+via
+a
+</ins><a class="tref internalDFN" title="context" href="#dfn-context"><ins class="diff-new">
+context
+</ins>
+</a>.
+</li>
+<del class="diff-old">Note
+</del>
+<li>
+A
+<del class="diff-old">Linked
+Data
+</del>
+<ins class="diff-chg">mechanism
+in
+which
+a
+value
+in
+a
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins>
+</a>
+<del class="diff-old">document
+does
+not
+necessarily
+need
+</del>
+<ins class="diff-chg">may
+refer
+</ins>
+to
+<del class="diff-old">be
+expressed
+in
+JSON-LD.
+The
+notion
+of
+Linked
+Data
+</del>
+<ins class="diff-chg">a
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins>
+</a>
+<del class="diff-old">is
+</del>
+<ins class="diff-chg">on
+</ins>
+a
+<del class="diff-old">concept
+independent
+of
+any
+given
+serialization
+format.
+In
+particular,
+any
+document
+based
+</del>
+<ins class="diff-chg">different
+site
+</ins>
+on
+<del class="diff-old">an
+RDF
+serialization
+format
+is
+</del>
+<ins class="diff-chg">the
+Web.
+</ins></li><li><ins class="diff-chg">
+The
+ability
+to
+express
+the
+language
+associated
+with
+</ins>
+a
+<del class="diff-old">Linked
+Data
+document.
+This
+definition
+of
+Linked
+Data
+</del>
+<a class="tref internalDFN" title="string" href="#dfn-string">
+<ins class="diff-chg">string
+</ins>
+</a>
+<del class="diff-old">is
+entirely
+consistent
+</del>
+<ins class="diff-chg">value.
+</ins></li><li><ins class="diff-chg">
+A
+way
+to
+associate
+datatypes
+</ins>
+with
+<del class="diff-old">that
+</del>
+<ins class="diff-chg">values
+such
+as
+dates,
+times,
+weights,
+and
+distances.
+</ins></li><li><ins class="diff-chg">
+A
+facility
+to
+express
+one
+or
+more
+directed
+graphs,
+such
+as
+a
+social
+network,
+</ins>
+in
+<del class="diff-old">[
+RDF-CONCEPTS
+],
+although
+Linked
+Data
+may
+not
+be
+</del>
+a
+<del class="diff-old">valid
+RDF
+document,
+</del>
+<ins class="diff-chg">single
+document.
+</ins></li></ol><p><ins class="diff-chg">
+Developers
+that
+require
+</ins>
+any
+<del class="diff-old">RDF
+document
+is
+an
+expression
+</del>
+of
+<del class="diff-old">Linked
+Data
+.
+</del>
+<ins class="diff-chg">the
+facilities
+listed
+above
+will
+find
+JSON-LD
+of
+interest.
+</ins>
+</p>
+</section>
+<section id="json-ld-data-model">
+<h3>
+<del class="diff-old">Issue
+</del>
+<span class="secno">
+<ins class="diff-chg">3.2
+</ins>
+</span>
+<del class="diff-old">An
+illustration
+of
+</del>
+<ins class="diff-chg">JSON-LD
+Data
+Model
+</ins></h3><p><dfn title="linked_data" id="dfn-linked_data"><ins class="diff-chg">
+Linked
+Data
+</ins></dfn><ins class="diff-chg">
+is
+</ins>
+a
+<del class="diff-old">linked
+</del>
+<ins class="diff-chg">way
+of
+publishing
+</ins>
+data
+<del class="diff-old">graph
+would
+probably
+help
+here.
+</del>
+<ins class="diff-chg">on
+the
+Web.
+In
+general,
+Linked
+Data
+has
+four
+properties;
+1)
+It
+uses
+</ins><a class="tref internalDFN" title="iri" href="#dfn-iri">
+<del class="diff-old">Issue
+47
+</del>
+<abbr title="Internationalized Resource Identifier">
+<ins class="diff-chg">IRI
+</ins></abbr>
+</a>
+<ins class="diff-new">s
+to
+name
+</ins><em><ins class="diff-new">
+things
+</ins></em>,<ins class="diff-new">
+2)
+It
+uses
+HTTP
+</ins><a class="tref internalDFN" title="iri" href="#dfn-iri">
+<del class="diff-old">Richard
+Cyganiak
+suggests
+that
+the
+data
+model
+is
+at
+odds
+with
+[
+</del>
+<abbr title="Internationalized Resource Identifier">
+<ins class="diff-chg">IRI
+</ins></abbr>
+<del class="diff-old">RDF-CONCEPTS
+</del>
+</a>
+<del class="diff-old">]
+and
+should
+be
+</del>
+<ins class="diff-chg">s
+for
+those
+names,
+3)
+The
+name
+links,
+when
+followed,
+provide
+</ins>
+more
+<del class="diff-old">closely
+aligned
+with
+it
+instead
+of
+creating
+new
+terminology.
+Note
+that
+this
+definition
+is
+provisional,
+</del>
+<ins class="diff-chg">information
+about
+the
+name,
+</ins>
+and
+<del class="diff-old">may
+be
+reverted
+</del>
+<ins class="diff-chg">4)
+The
+data
+expresses
+links
+</ins>
+to
+<del class="diff-old">something
+closer
+</del>
+<ins class="diff-chg">data
+on
+other
+Web
+sites.
+These
+properties
+allow
+data
+published
+on
+the
+Web
+</ins>
+to
+<ins class="diff-new">work
+much
+like
+Web
+pages
+do
+today.
+One
+can
+start
+at
+one
+piece
+of
+Linked
+Data,
+and
+follow
+</ins>
+the
+<del class="diff-old">original
+depending
+</del>
+<ins class="diff-chg">links
+to
+other
+pieces
+of
+data
+that
+are
+hosted
+</ins>
+on
+<del class="diff-old">community
+feedback.
+</del>
+<ins class="diff-chg">different
+sites
+across
+the
+Web.
+</ins>
+</p>
+<p>
+<ins class="diff-chg">JSON-LD
+is
+a
+way
+of
+expressing
+</ins>
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+<ins class="diff-new">on
+the
+Web.
+The
+JSON-LD
+data
+model
+encapsulates
+the
+following
+concepts:
+</ins></p><ol><li><ins class="diff-new">
+The
+JSON-LD
+data
+model
+</ins>
+is
+<del class="diff-old">a
+set
+of
+documents,
+each
+containing
+a
+representation
+of
+a
+</del>
+<ins class="diff-chg">used
+to
+represent
+</ins>
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+<del class="diff-old">.
+</del>
+</a>
+<ins class="diff-chg">s.
+</ins>
+</li>
+<li>
+A
+<dfn title="linked_data_graph" id="dfn-linked_data_graph">
+linked
+data
+graph
+</dfn>
+is
+an
+unordered
+labeled
+directed
+graph,
+where
+<del class="diff-old">nodes
+are
+</del>
+<ins class="diff-chg">each
+</ins><dfn title="node" id="dfn-node"><ins class="diff-chg">
+node
+</ins></dfn><ins class="diff-chg">
+is
+a
+</ins><a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+<del class="diff-old">s
+</del>
+</a>
+or
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+<del class="diff-old">s,
+</del>
+</a>,
+and
+edges
+are
+labeled
+using
+<a class="tref internalDFN" title="property" href="#dfn-property">
+properties
+</a>.
+</li>
+<li>
+A
+<dfn title="subject" id="dfn-subject">
+subject
+</dfn>
+is
+any
+node
+in
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+with
+at
+least
+one
+outgoing
+edge.
+</li>
+<li>
+A
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+<em class="rfc2119" title="should">
+should
+</em>
+be
+labeled
+with
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(an
+Internationalized
+Resource
+Identifier
+as
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC3987">
+RFC3987
+</a>
+</cite>
+]).
+</li>
+<li>
+An
+<dfn title="object" id="dfn-object">
+object
+</dfn>
+is
+a
+node
+in
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+with
+at
+least
+one
+incoming
+edge.
+</li>
+<li>
+An
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+be
+labeled
+with
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+a
+label
+that
+is
+not
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+such
+as
+plain
+text,
+internationalized
+text,
+or
+a
+strictly-typed
+data
+value.
+</li>
+<li>
+A
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+be
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+and
+an
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+at
+the
+same
+time.
+</li>
+<li>
+A
+<dfn title="property" id="dfn-property">
+property
+</dfn>
+is
+the
+label
+on
+an
+edge
+in
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>.
+</li>
+<li>
+A
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>
+<em class="rfc2119" title="should">
+should
+</em>
+be
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</li>
+<li>
+An
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+that
+is
+a
+label
+in
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+<em class="rfc2119" title="should">
+should
+</em>
+be
+dereferencable
+to
+a
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+document
+describing
+the
+labeled
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+<del class="diff-old">,
+</del>
+</a>,
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>
+or
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+<del class="diff-old">.
+</del>
+</a>.
+</li>
+</ol>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<del class="diff-old">JSON-LD
+allows
+properties
+to
+be
+BNodes,
+while
+RDF
+</del>
+<div class="">
+<p>
+<ins class="diff-chg">A
+</ins><a class="tref internalDFN" title="linked_data" href="#dfn-linked_data"><ins class="diff-chg">
+Linked
+Data
+</ins></a><ins class="diff-chg">
+document
+</ins>
+does
+<del class="diff-old">not.
+When
+used
+as
+just
+JSON-LD,
+this
+is
+</del>
+not
+<del class="diff-old">unreasonable;
+it
+only
+becomes
+an
+issue
+(and
+could
+raise
+an
+exception)
+when
+transformed
+</del>
+<ins class="diff-chg">necessarily
+need
+</ins>
+to
+<del class="diff-old">RDF.
+Note
+that
+the
+definition
+for
+</del>
+<ins class="diff-chg">be
+expressed
+in
+JSON-LD.
+The
+notion
+of
+</ins>
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+<del class="diff-old">above
+</del>
+is
+<del class="diff-old">silent
+on
+the
+topic
+</del>
+<ins class="diff-chg">a
+concept
+independent
+</ins>
+of
+<del class="diff-old">unlabeled
+nodes
+.
+Nevertheless,
+this
+specification
+allows
+for
+the
+expression
+</del>
+<ins class="diff-chg">any
+given
+serialization
+format.
+</ins></p></div></div><img style="padding: 5px; border-style: solid; border-width: 1px; display: block; margin-left: auto; margin-right: auto;" src="linked-data-graph.png" title="An example of a linked data graph" longdesc="An example of a linked data graph showing two main nodes labeled with URLs for Alice and Bob. The Alice node contains two other connected nodes showing Alice's age (32) and name (Alice)." /><p style="text-align: center;"><ins class="diff-chg">
+Figure
+1:
+An
+example
+</ins>
+of
+<del class="diff-old">unlabeled
+nodes
+,
+as
+most
+graph-based
+</del>
+<ins class="diff-chg">a
+linked
+</ins>
+data
+<del class="diff-old">sets
+on
+the
+Web
+contain
+</del>
+<ins class="diff-chg">graph.
+</ins></p><p><ins class="diff-chg">
+There
+are
+</ins>
+a
+number
+of
+<del class="diff-old">associated
+nodes
+</del>
+<ins class="diff-chg">best
+practices
+</ins>
+that
+<del class="diff-old">are
+not
+named
+and
+thus
+are
+not
+directly
+de-referenceable.
+</del>
+<ins class="diff-chg">can
+ensure
+that
+developers
+will
+generate
+good
+Linked
+Data
+for
+the
+Web.
+</ins>
+JSON-LD
+<del class="diff-old">defines
+</del>
+<ins class="diff-chg">formalizes
+those
+techniques
+by
+providing
+</ins>
+a
+mechanism
+to
+map
+JSON
+<del class="diff-old">terms,
+</del>
+<ins class="diff-chg">data,
+</ins>
+i.e.,
+keys
+and
+values,
+to
+<del class="diff-old">IRIs.
+</del>
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+<ins class="diff-chg">IRI
+</ins></abbr></a><ins class="diff-chg">
+s.
+</ins>
+This
+does
+not
+mean
+that
+JSON-LD
+requires
+every
+key
+or
+value
+to
+be
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>,
+but
+rather
+ensures
+that
+keys
+and
+values
+can
+be
+mapped
+to
+IRIs
+if
+the
+developer
+desires
+to
+transform
+their
+data
+into
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>.
+<del class="diff-old">There
+are
+a
+few
+techniques
+that
+can
+ensure
+that
+developers
+will
+generate
+good
+Linked
+Data
+for
+the
+Web.
+JSON-LD
+formalizes
+those
+techniques.
+</del>
+</p>
+</section>
+<section id="general-terminology">
+<h3>
+<span class="secno">
+<ins class="diff-new">3.3
+</ins></span><ins class="diff-new">
+General
+Terminology
+</ins></h3>
+<p>
+<del class="diff-old">We
+will
+</del>
+<ins class="diff-chg">The
+following
+is
+an
+explanation
+of
+the
+general
+terminology
+used
+in
+this
+document.
+Many
+of
+the
+terms
+should
+</ins>
+be
+<del class="diff-old">using
+</del>
+<ins class="diff-chg">familiar
+to
+developers
+that
+have
+used
+JSON:
+</ins></p><dl><dt><dfn title="json_object" id="dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></dfn></dt><dd><ins class="diff-chg">
+An
+object
+structure
+is
+represented
+as
+a
+pair
+of
+curly
+brackets
+surrounding
+zero
+or
+more
+key-value
+pairs.
+A
+key
+is
+a
+</ins><a class="tref internalDFN" title="string" href="#dfn-string"><ins class="diff-chg">
+string
+</ins></a>.<ins class="diff-chg">
+A
+single
+colon
+comes
+after
+each
+key,
+separating
+</ins>
+the
+<ins class="diff-new">key
+from
+the
+value.
+A
+single
+comma
+separates
+a
+value
+from
+a
+</ins>
+following
+<ins class="diff-new">key.
+The
+keys
+within
+an
+object
+</ins><em class="rfc2119" title="should"><ins class="diff-new">
+should
+</ins></em><ins class="diff-new">
+be
+unique.
+</ins></dd><dt><dfn title="array" id="dfn-array"><ins class="diff-new">
+array
+</ins></dfn></dt><dd><ins class="diff-new">
+In
+JSON,
+an
+array
+is
+an
+</ins><em><ins class="diff-new">
+ordered
+</ins></em><ins class="diff-new">
+sequence
+of
+zero
+or
+more
+values.
+An
+array
+is
+represented
+as
+square
+brackets
+surrounding
+zero
+or
+more
+values
+that
+are
+separated
+by
+commas.
+While
+JSON-LD
+uses
+the
+same
+array
+representation
+as
+JSON,
+the
+collection
+is
+</ins><em><ins class="diff-new">
+unordered
+</ins></em><ins class="diff-new">
+by
+default.
+While
+order
+is
+preserved
+in
+regular
+</ins>
+JSON
+<ins class="diff-new">arrays,
+it
+is
+not
+in
+regular
+JSON-LD
+arrays
+unless
+specific
+</ins>
+markup
+<ins class="diff-new">is
+provided
+(see
+</ins><a href="#sets-and-lists" class="sec-ref"><span class="secno"><ins class="diff-new">
+4.9
+</ins></span><span class="sec-title"><ins class="diff-new">
+Sets
+and
+Lists
+</ins></span></a><ins class="diff-new">
+).
+</ins></dd><dt><dfn title="string" id="dfn-string"><ins class="diff-new">
+string
+</ins></dfn></dt><dd><ins class="diff-new">
+A
+string
+is
+a
+sequence
+of
+zero
+or
+more
+Unicode
+characters,
+wrapped
+in
+double
+quotes,
+using
+backslash
+escapes
+(if
+necessary).
+A
+character
+is
+represented
+</ins>
+as
+<ins class="diff-new">a
+single
+character
+string.
+</ins></dd><dt><dfn title="number" id="dfn-number"><ins class="diff-new">
+number
+</ins></dfn></dt><dd><ins class="diff-new">
+A
+number
+is
+similar
+to
+that
+used
+in
+most
+programming
+languages,
+except
+that
+</ins>
+the
+<del class="diff-old">example
+for
+</del>
+<ins class="diff-chg">octal
+and
+hexadecimal
+formats
+are
+not
+used
+and
+that
+leading
+zeros
+are
+not
+allowed.
+</ins></dd><dt><dfn title="true" id="dfn-true"><ins class="diff-chg">
+true
+</ins></dfn><ins class="diff-chg">
+and
+</ins><dfn title="false" id="dfn-false"><ins class="diff-chg">
+false
+</ins></dfn></dt><dd><ins class="diff-chg">
+Values
+that
+are
+used
+to
+express
+one
+of
+two
+possible
+boolean
+states.
+</ins></dd><dt><dfn title="null" id="dfn-null"><ins class="diff-chg">
+null
+</ins></dfn></dt><dd><ins class="diff-chg">
+The
+null
+value
+is
+used
+to
+make
+a
+JSON-LD
+processor
+"forget"
+any
+previously
+defined
+JSON
+key
+that
+is
+associated
+with
+</ins>
+the
+<del class="diff-old">rest
+</del>
+<ins class="diff-chg">null
+value.
+If
+a
+previous
+definition
+doesn't
+exist,
+the
+entire
+key-value
+is
+ignored.
+If
+a
+previous
+definition
+</ins>
+of
+<del class="diff-old">this
+section:
+{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</del>
+<ins class="diff-chg">the
+key
+does
+exist,
+the
+previous
+definition
+is
+undefined.
+</ins></dd><dt>
+<dfn title="node_definition" id="dfn-node_definition">
+<ins class="diff-chg">node
+definition
+</ins></dfn></dt><dd><ins class="diff-chg">
+A
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></a><ins class="diff-chg">
+used
+to
+represent
+a
+</ins><a class="tref internalDFN" title="node" href="#dfn-node"><ins class="diff-chg">
+node
+</ins></a><ins class="diff-chg">
+and
+one
+or
+more
+properties
+of
+that
+node.
+A
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></a><ins class="diff-chg">
+is
+a
+node
+definition
+if
+it
+does
+not
+contain
+the
+keys
+</ins><code><ins class="diff-chg">
+@value
+</ins></code>,<code><ins class="diff-chg">
+@list
+</ins></code><ins class="diff-chg">
+or
+</ins><code><ins class="diff-chg">
+@set
+</ins></code><ins class="diff-chg">
+and
+it
+has
+one
+or
+more
+keys
+other
+than
+</ins><code><ins class="diff-chg">
+@id
+</ins></code>.<ins class="diff-chg">
+A
+node
+definition
+</ins><em class="rfc2119" title="may"><ins class="diff-chg">
+may
+</ins></em><ins class="diff-chg">
+be
+spread
+among
+different
+parts
+of
+a
+document
+or
+even
+between
+different
+documents.
+</ins></dd><dt><dfn title="node_reference" id="dfn-node_reference"><ins class="diff-chg">
+node
+reference
+</ins></dfn></dt><dd><ins class="diff-chg">
+A
+</ins><a class="tref internalDFN" title="json_object" href="#dfn-json_object"><ins class="diff-chg">
+JSON
+object
+</ins></a><ins class="diff-chg">
+used
+to
+refer
+to
+a
+node
+that
+contains
+a
+single
+key-value
+pair
+where
+the
+key
+is
+</ins><code><ins class="diff-chg">
+@id
+</ins></code>.</dd></dl><p></p>
+</section>
+<section id="syntax-tokens-and-keywords">
+<h3>
+<span class="secno">
+<del class="diff-old">3.2
+</del>
+<ins class="diff-chg">3.4
+</ins>
+</span>
+Syntax
+Tokens
+and
+Keywords
+</h3>
+<p>
+JSON-LD
+specifies
+a
+number
+of
+syntax
+tokens
+and
+<dfn title="keyword" id="dfn-keyword">
+keywords
+</dfn>
+that
+are
+a
+core
+part
+of
+the
+language:
+</p>
+<dl>
+<dt>
+<code>
+@context
+</code>
+</dt>
+<dd>
+Used
+to
+define
+the
+short-hand
+names
+that
+are
+used
+throughout
+a
+JSON-LD
+document.
+These
+short-hand
+names
+are
+called
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+and
+help
+developers
+to
+express
+specific
+identifiers
+in
+a
+compact
+manner.
+The
+<code>
+@context
+</code>
+keyword
+is
+described
+in
+detail
+in
+the
+section
+titled
+<a href="#the-context" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.3
+</del>
+<ins class="diff-chg">3.5
+</ins>
+</span>
+<span class="sec-title">
+The
+Context
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@graph
+</code>
+</dt>
+<dd>
+Used
+to
+explicitly
+label
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>.
+This
+keyword
+is
+described
+in
+<a href="#named-graphs" class="sec-ref">
+<span class="secno">
+4.11
+</span>
+<span class="sec-title">
+Named
+Graphs
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@id
+</code>
+</dt>
+<dd>
+Used
+to
+uniquely
+identify
+<em>
+things
+</em>
+that
+are
+being
+described
+in
+the
+document.
+This
+keyword
+is
+described
+in
+<a href="#node-identifiers" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.6
+</del>
+<ins class="diff-chg">3.8
+</ins>
+</span>
+<span class="sec-title">
+Node
+Identifiers
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@value
+</code>
+</dt>
+<dd>
+Used
+to
+specify
+the
+data
+that
+is
+associated
+with
+a
+particular
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>
+in
+the
+graph.
+This
+keyword
+is
+described
+in
+<a href="#string-internationalization" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.8
+</del>
+<ins class="diff-chg">3.10
+</ins>
+</span>
+<span class="sec-title">
+String
+Internationalization
+</span>
+</a>
+and
+<a href="#typed-values" class="sec-ref">
+<span class="secno">
+4.2
+</span>
+<span class="sec-title">
+Typed
+Values
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@language
+</code>
+</dt>
+<dd>
+Used
+to
+specify
+the
+native
+language
+for
+a
+particular
+value
+or
+the
+default
+language
+of
+a
+JSON-LD
+document.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#string-internationalization" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.8
+</del>
+<ins class="diff-chg">3.10
+</ins>
+</span>
+<span class="sec-title">
+String
+Internationalization
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@type
+</code>
+</dt>
+<dd>
+Used
+to
+set
+the
+data
+type
+of
+a
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>
+or
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#typed-values" class="sec-ref">
+<span class="secno">
+4.2
+</span>
+<span class="sec-title">
+Typed
+Values
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@container
+</code>
+</dt>
+<dd>
+Used
+to
+set
+the
+container
+of
+a
+particular
+value.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@list
+</code>
+</dt>
+<dd>
+Used
+to
+express
+an
+ordered
+set
+of
+data.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@set
+</code>
+</dt>
+<dd>
+Used
+to
+express
+an
+unordered
+set
+of
+data.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>.
+</dd>
+<dt>
+<code>
+@vocab
+</code>
+</dt>
+<dd>
+Used
+to
+set
+the
+base
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+for
+all
+property
+IRIs
+affected
+by
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+This
+keyword
+is
+described
+in
+section
+<a href="#iris" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.5
+</del>
+<ins class="diff-chg">3.7
+</ins>
+</span>
+<span class="sec-title">
+IRIs
+</span>
+</a>.
+</dd>
+<dt>
+<code>:
+</code>
+</dt>
+<dd>
+The
+separator
+for
+JSON
+keys
+and
+values
+that
+use
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+IRIs
+</a>.
+</dd>
+</dl>
+<p>
+For
+the
+avoidance
+of
+doubt,
+all
+keys,
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>,
+and
+values
+in
+JSON-LD
+are
+case-sensitive.
+</p>
+</section>
+<section id="the-context">
+<h3>
+<span class="secno">
+<del class="diff-old">3.3
+</del>
+<ins class="diff-chg">3.5
+</ins>
+</span>
+The
+Context
+</h3>
+<p>
+In
+JSON-LD,
+a
+<dfn title="context" id="dfn-context">
+context
+</dfn>
+is
+used
+to
+map
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s,
+i.e.,
+properties
+with
+associated
+values
+in
+an
+JSON
+document,
+to
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s.
+A
+<dfn title="term" id="dfn-term">
+term
+</dfn>
+is
+a
+short
+word
+that
+expands
+to
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Term
+</a>
+s
+<em class="rfc2119" title="may">
+may
+</em>
+be
+defined
+as
+any
+valid
+JSON
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+other
+than
+a
+JSON-LD
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+To
+avoid
+forward-compatibility
+issues,
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+starting
+with
+an
+<code>
+@
+</code>
+character
+<em class="rfc2119" title="should not">
+should
+not
+</em>
+be
+used
+as
+they
+might
+be
+used
+as
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>
+in
+future
+versions
+of
+JSON-LD.
+Furthermore,
+the
+use
+of
+empty
+terms
+(
+<code>
+""
+</code>
+)
+is
+discouraged
+as
+not
+all
+programming
+languages
+are
+able
+to
+handle
+empty
+property
+names.
+</p>
+<p>
+The
+Web
+uses
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+IRIs
+</a>
+for
+unambiguous
+identification.
+The
+idea
+is
+that
+these
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+mean
+something
+that
+may
+be
+of
+use
+to
+other
+developers
+and
+that
+it
+is
+useful
+to
+give
+them
+an
+unambiguous
+identifier.
+That
+is,
+it
+is
+useful
+for
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+to
+expand
+to
+IRIs
+so
+that
+developers
+don't
+accidentally
+step
+on
+each
+other's
+<dfn title="vocabulary" id="dfn-vocabulary">
+vocabulary
+</dfn>
+terms
+and
+other
+resources.
+Furthermore,
+developers,
+and
+machines,
+are
+able
+to
+use
+this
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(by
+plugging
+it
+directly
+into
+a
+web
+browser,
+for
+instance)
+to
+go
+to
+the
+term
+and
+get
+a
+definition
+of
+what
+the
+term
+means.
+This
+mechanism
+is
+analogous
+to
+the
+way
+we
+can
+use
+<a href="http://wordnet.princeton.edu/">
+WordNet
+</a>
+today
+to
+see
+the
+definition
+of
+words
+in
+the
+English
+language.
+Developers
+and
+machines
+need
+the
+same
+sort
+of
+definition
+of
+terms.
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+IRIs
+</a>
+provide
+a
+way
+to
+ensure
+that
+these
+terms
+are
+unambiguous.
+For
+example,
+the
+term
+<code>
+name
+</code>
+may
+map
+directly
+to
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>.
+This
+allows
+JSON-LD
+documents
+to
+be
+constructed
+using
+the
+common
+JSON
+practice
+of
+simple
+<del class="diff-old">name/value
+</del>
+<ins class="diff-chg">key-value
+</ins>
+pairs
+while
+ensuring
+that
+the
+data
+is
+useful
+outside
+of
+the
+page,
+API
+or
+database
+in
+which
+it
+resides.
+The
+value
+of
+a
+term
+mapping
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either;
+1)
+a
+simple
+string
+with
+the
+lexical
+form
+of
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+2)
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+3)
+an
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+an
+<code>
+@id
+</code>,
+<code>
+@type
+</code>,
+<code>
+@language
+</code>,
+or
+<code>
+@container
+</code>
+keyword
+(all
+other
+keywords
+are
+ignored
+by
+a
+JSON-LD
+processor).
+</p>
+<p>
+These
+Linked
+Data
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+are
+typically
+collected
+in
+a
+context
+document
+that
+would
+look
+something
+like
+this:
+</p>
+<del class="diff-old">{
+</del>
+<div class="example"><div class="example-title"><span>Example 1</span>: Context definition</div><pre class="example">{
+ "@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "depiction":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/depiction",
+ "@type": "@id"
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ },
+ }
+}
+</pre>
+</div>
+<p>
+<del class="diff-old">Assuming
+</del>
+<ins class="diff-chg">Let's
+assume
+</ins>
+that
+<del class="diff-old">this
+context
+document
+can
+be
+retrieved
+at
+http://json-ld.org/contexts/person.jsonld
+,
+it
+can
+be
+referenced
+from
+</del>
+a
+<del class="diff-old">JSON-LD
+document
+by
+adding
+</del>
+<ins class="diff-chg">developer
+starts
+with
+the
+following
+JSON
+document:
+</ins></p><div class="example"><div class="example-title"><span>Example 2</span>: Sample JSON object</div><pre class="example">{<ins class="diff-chg">
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</ins></pre></div><p><ins class="diff-chg">
+The
+developer
+can
+add
+</ins>
+a
+single
+<del class="diff-old">line.
+The
+</del>
+<ins class="diff-chg">line
+to
+the
+</ins>
+JSON
+<del class="diff-old">markup
+shown
+in
+</del>
+<ins class="diff-chg">document
+above
+to
+reference
+</ins>
+the
+<del class="diff-old">previous
+section
+could
+be
+changed
+as
+follows:
+</del>
+<ins class="diff-chg">context
+and
+transform
+it
+into
+a
+JSON-LD
+document:
+</ins>
+</p>
+<div class="example"><div class="example-title"><span>Example 3</span>: Adding context reference to JSON document</div><pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person.jsonld",</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+The
+additions
+above
+transform
+the
+previous
+JSON
+document
+into
+a
+JSON
+document
+with
+added
+semantics
+because
+the
+<code>
+@context
+</code>
+specifies
+how
+the
+<strong>
+name
+</strong>,
+<strong>
+homepage
+</strong>,
+and
+<strong>
+depiction
+</strong>
+terms
+map
+to
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+IRIs
+</a>.
+Mapping
+those
+keys
+to
+IRIs
+gives
+the
+data
+global
+context.
+If
+two
+developers
+use
+the
+same
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+to
+describe
+a
+property,
+they
+are
+more
+than
+likely
+expressing
+the
+same
+concept.
+This
+allows
+both
+developers
+to
+re-use
+each
+others'
+data
+without
+having
+to
+agree
+to
+how
+their
+data
+will
+interoperate
+on
+a
+site-by-site
+basis.
+Contexts
+may
+also
+contain
+type
+information
+for
+certain
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+as
+well
+as
+other
+processing
+instructions
+for
+the
+JSON-LD
+processor.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+External
+JSON-LD
+context
+documents
+<em class="rfc2119" title="may">
+may
+</em>
+contain
+extra
+information
+located
+outside
+of
+the
+<code>
+@context
+</code>
+key,
+such
+as
+documentation
+about
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+terms
+</a>
+declared
+in
+the
+document.
+When
+importing
+a
+<code>
+@context
+</code>
+value
+from
+an
+external
+JSON-LD
+context
+document,
+any
+extra
+information
+contained
+outside
+of
+the
+<code>
+@context
+</code>
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+discarded.
+</p>
+</div>
+<p>
+Contexts
+<em class="rfc2119" title="may">
+may
+</em>
+be
+specified
+in-line.
+This
+ensures
+that
+JSON-LD
+documents
+can
+be
+processed
+when
+a
+JSON-LD
+processor
+does
+not
+have
+access
+to
+the
+Web.
+</p>
+<div class="example"><div class="example-title"><span>Example 4</span>: In-line context definition</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "depiction":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/depiction",
+ "@type": "@id"
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ },
+ },</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+Contexts
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+at
+any
+time
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+is
+defined.
+A
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+specify
+multiple
+contexts,
+using
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>,
+which
+is
+processed
+in
+order.
+This
+is
+useful
+when
+an
+author
+would
+like
+to
+use
+an
+existing
+context
+and
+add
+application-specific
+terms
+to
+the
+existing
+context.
+Duplicate
+context
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+<em class="rfc2119" title="must">
+must
+</em>
+be
+overridden
+using
+a
+last-defined-overrides
+mechanism.
+</p>
+<div class="example"><div class="example-title"><span>Example 5</span>: Scoped contexts within node definitions</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "name": "http://example.com/person#name",
+ "details": "http://example.com/person#details"
+ },</span>
+ "<span class="diff">name</span>": "Markus Lanthaler",
+ ...
+ "details":
+ {
+ <span class="diff">"@context": {
+ "name": "http://example.com/organization#name"
+ },</span>
+ "<span class="diff">name</span>": "Graz University of Technology"
+ }
+}
+</pre>
+</div>
+<p>
+In
+the
+example
+above,
+the
+<code>
+name
+</code>
+prefix
+is
+overridden
+in
+the
+more
+deeply
+nested
+<code>
+details
+</code>
+structure.
+Note
+that
+this
+is
+rarely
+a
+good
+authoring
+practice
+and
+is
+typically
+used
+when
+there
+exist
+legacy
+applications
+that
+depend
+on
+the
+specific
+structure
+of
+the
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+If
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+is
+re-defined
+within
+a
+context,
+all
+previous
+rules
+associated
+with
+the
+previous
+definition
+are
+removed.
+A
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+in
+a
+previous
+context
+<em class="rfc2119" title="must">
+must
+</em>
+be
+removed,
+if
+it
+is
+re-defined
+to
+<code>
+null
+</code>.
+</p>
+</div>
+<p>
+The
+set
+of
+contexts
+defined
+within
+a
+specific
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+are
+referred
+to
+as
+<dfn title="local_context" id="dfn-local_context">
+local
+context
+</dfn>
+s.
+Setting
+the
+context
+to
+<code>
+null
+</code>
+effectively
+resets
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+to
+an
+empty
+context.
+The
+<dfn title="active_context" id="dfn-active_context">
+active
+context
+</dfn>
+refers
+to
+the
+accumulation
+of
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+s
+that
+are
+in
+scope
+at
+a
+specific
+point
+within
+the
+document.
+The
+following
+example
+specifies
+an
+external
+context
+and
+then
+layers
+a
+local
+context
+on
+top
+of
+the
+external
+context:
+</p>
+<div class="example"><div class="example-title"><span>Example 6</span>: Combining external and local contexts</div><pre class="example">{
+ <span class="diff">"@context": [
+ "http://json-ld.org/contexts/person.jsonld",
+ {
+ "pic": "http://xmlns.com/foaf/0.1/depiction"
+ }
+ ],</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ <span class="diff">"pic": "http://twitter.com/account/profile_image/manusporny"</span>
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+To
+ensure
+the
+best
+possible
+performance,
+it
+is
+a
+best
+practice
+to
+put
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition
+at
+the
+top
+of
+the
+JSON-LD
+document.
+If
+it
+isn't
+listed
+first,
+processors
+have
+to
+save
+each
+key-value
+pair
+until
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+is
+processed.
+This
+creates
+a
+memory
+and
+complexity
+burden
+for
+certain
+types
+of
+low-memory
+footprint
+JSON-LD
+processors.
+</p>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+The
+<code>
+null
+</code>
+value
+is
+processed
+in
+a
+special
+way
+in
+JSON-LD.
+Unless
+otherwise
+specified,
+a
+JSON-LD
+processor
+<em class="rfc2119" title="must">
+must
+</em>
+act
+as
+if
+a
+key-value
+pair
+in
+the
+body
+of
+a
+JSON-LD
+document
+was
+never
+declared
+when
+the
+value
+equals
+<em>
+null
+</em>.
+If
+<code>
+@value
+</code>,
+<code>
+@list
+</code>,
+or
+<code>
+@set
+</code>
+is
+set
+to
+<em>
+null
+</em>
+in
+expanded
+form,
+then
+the
+entire
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+ignored.
+If
+<code>
+@context
+</code>
+is
+set
+to
+<em>
+null
+</em>,
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+is
+reset
+and
+when
+used
+within
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>,
+it
+removes
+any
+definition
+associated
+with
+the
+key,
+unless
+otherwise
+specified.
+</p>
+</div>
+</section>
+<section id="from-json-to-json-ld">
+<h3>
+<span class="secno">
+<del class="diff-old">3.4
+</del>
+<ins class="diff-chg">3.6
+</ins>
+</span>
+From
+JSON
+to
+JSON-LD
+</h3>
+<p>
+If
+a
+set
+of
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+such
+as,
+<strong>
+name
+</strong>,
+<strong>
+homepage
+</strong>,
+and
+<strong>
+depiction
+</strong>,
+are
+defined
+in
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>,
+and
+that
+context
+is
+used
+to
+resolve
+the
+names
+in
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+objects
+</a>,
+machines
+are
+able
+to
+automatically
+expand
+the
+terms
+to
+something
+meaningful
+and
+unambiguous,
+like
+this:
+</p>
+<div class="example"><div class="example-title"><span>Example 7</span>: Expanded terms</div><pre class="example">{
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+ "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>": "http://manu.sporny.org"
+ "<span class="diff">http://xmlns.com/foaf/0.1/depiction</span>": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+Doing
+this
+allows
+JSON
+to
+be
+unambiguously
+machine-readable
+without
+requiring
+developers
+to
+drastically
+change
+their
+workflow.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+The
+example
+above
+does
+not
+use
+the
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+to
+identify
+the
+node
+being
+described
+above.
+This
+type
+of
+node
+is
+called
+an
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>.
+It
+is
+advised
+that
+all
+nodes
+described
+in
+JSON-LD
+are
+given
+unique
+identifiers
+via
+the
+<code>
+@id
+</code>
+keyword
+unless
+the
+data
+is
+not
+intended
+to
+be
+linked
+to
+from
+other
+data
+sets.
+</p>
+</div>
+<p>
+A
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+used
+to
+define
+property
+values
+is
+called
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>.
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+Node
+definitions
+</a>
+do
+not
+require
+an
+<code>
+@id
+</code>.
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+Node
+definitions
+</a>
+that
+do
+not
+contain
+an
+<code>
+@id
+</code>
+are
+known
+as
+an
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+nodes
+</a>.
+</p>
+</section>
+<section id="iris">
+<h3>
+<span class="secno">
+<del class="diff-old">3.5
+</del>
+<ins class="diff-chg">3.7
+</ins>
+</span>
+IRIs
+</h3>
+<p>
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+IRIs
+</a>
+are
+fundamental
+to
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+as
+that
+is
+how
+most
+<a class="tref internalDFN" title="node" href="#dfn-node">
+nodes
+</a>
+s
+and
+all
+<a class="tref internalDFN" title="property" href="#dfn-property">
+properties
+</a>
+are
+identified.
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+can
+be
+expressed
+in
+a
+variety
+of
+different
+ways
+in
+JSON-LD.
+</p>
+<p>
+An
+<dfn title="iri" id="dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+(an
+Internationalized
+Resource
+Identifier)
+is
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC3987">
+RFC3987
+</a>
+</cite>
+])
+and
+the
+use
+with
+JSON-LD
+conforms
+to
+the
+definition
+of
+<cite>
+<a href="http://www.w3.org/TR/rdf11-concepts/#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+</cite>
+in
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+].
+</p>
+<ol>
+<li>
+Except
+within
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition,
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+in
+the
+key
+position
+in
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+that
+have
+a
+mapping
+or
+a
+vocabulary
+base
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+are
+expanded
+to
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+by
+JSON-LD
+processors.
+</li>
+<li>
+An
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+generated
+for
+the
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+value
+specified
+using
+<code>
+@id
+</code>
+or
+<code>
+@type
+</code>.
+</li>
+<li>
+An
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+generated
+for
+the
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+value
+of
+any
+key
+for
+which
+there
+are
+<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
+coercion
+</a>
+rules
+in
+effect
+that
+identify
+the
+value
+as
+an
+<code>
+@id
+</code>.
+</li>
+</ol>
+<p>
+IRIs
+may
+be
+represented
+as
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+a
+<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
+relative
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+as
+a
+value
+relative
+to
+<code>
+@vocab
+</code>.
+</p>
+<p>
+An
+<dfn title="absolute_iri" id="dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+is
+defined
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC3987">
+RFC3987
+</a>
+</cite>
+]
+containing
+a
+<em>
+scheme
+</em>
+along
+with
+<em>
+path
+</em>
+and
+optional
+<em>
+query
+</em>
+and
+<em>
+fragment
+</em>
+segments.
+A
+<dfn title="relative_iri" id="dfn-relative_iri">
+relative
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+is
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+that
+is
+relative
+to
+some
+other
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+In
+JSON-LD
+all
+<a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">
+relative
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+are
+resolved
+relative
+to
+the
+<dfn title="base_iri" id="dfn-base_iri">
+base
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+associated
+with
+the
+document
+(typically,
+the
+directory
+that
+contains
+the
+document
+or
+the
+document
+itself).
+</p>
+<p>
+IRIs
+can
+be
+expressed
+directly
+in
+the
+key
+position
+like
+so:
+</p>
+<div class="example"><div class="example-title"><span>Example 8</span>: IRI as a key</div><pre class="example">{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}
+</pre>
+</div>
+<p>
+In
+the
+example
+above,
+the
+key
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>
+is
+interpreted
+as
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+because
+it
+contains
+a
+colon
+(
+<code>:
+</code>
+)
+and
+the
+'http'
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+does
+not
+exist
+in
+the
+context.
+</p>
+<p>
+Term
+expansion
+occurs
+for
+IRIs
+if
+the
+value
+matches
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+within
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 9</span>: Term expansion from context definition</div><pre class="example">{
+ "<span class="diff">@context</span>":
+ {
+ "<span class="diff">name</span>": "<span class="diff">http://xmlns.com/foaf/0.1/name</span>"
+...
+ },
+ "<span class="diff">name</span>": "Manu Sporny",
+ "status": "trollin'",
+...
+}
+</pre>
+</div>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Term
+</a>
+s
+are
+case
+sensitive,
+and
+<em class="rfc2119" title="must">
+must
+</em>
+be
+matched
+using
+a
+case-sensitive
+comparison.
+</p>
+<p>
+JSON
+keys
+that
+do
+not
+expand
+to
+an
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+are
+ignored,
+or
+removed
+in
+some
+cases,
+by
+the
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+However,
+JSON
+keys
+that
+do
+not
+include
+a
+mapping
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+are
+still
+considered
+valid
+expressions
+in
+JSON-LD
+documents
+-
+the
+keys
+just
+don't
+have
+any
+machine-readable,
+semantic
+meaning.
+</p>
+<p>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+Prefix
+</a>
+es
+are
+expanded
+when
+the
+form
+of
+the
+value
+is
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+represented
+as
+a
+<code>
+prefix:suffix
+</code>
+combination,
+and
+the
+prefix
+matches
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+within
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 10</span>: Prefix expansion</div><pre class="example">{
+ "<span class="diff">@context</span>":
+ {
+ "<span class="diff">foaf</span>": "<span class="diff">http://xmlns.com/foaf/0.1/</span>"
+...
+ },
+ "<span class="diff">foaf:name</span>": "Manu Sporny",
+...
+}
+</pre>
+</div>
+<p>
+<code>
+foaf:name
+</code>
+above
+will
+automatically
+expand
+out
+to
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>.
+See
+<a href="#compact-iris" class="sec-ref">
+<span class="secno">
+4.1
+</span>
+<span class="sec-title">
+Compact
+IRIs
+</span>
+</a>
+for
+more
+details.
+</p>
+<p>
+If
+the
+<code>
+@vocab
+</code>
+is
+set,
+all
+keys
+that
+do
+not
+match
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+or
+a
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+are
+It
+is
+often
+common
+that
+all
+types
+and
+properties
+come
+from
+the
+same
+vocabulary.
+JSON-LD's
+<code>
+@vocab
+</code>
+keyword
+allows
+to
+set
+a
+base
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+to
+be
+used
+for
+all
+properties
+and
+types
+that
+that
+do
+not
+match
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+a
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>,
+or
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(i.e.,
+do
+not
+contain
+a
+colon).
+The
+<code>
+@vocab
+</code>
+mapping
+<em class="rfc2119" title="must">
+must
+</em>
+have
+a
+value
+of
+a
+simple
+string
+with
+the
+lexical
+form
+of
+an
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>.
+</p>
+<div class="example"><div class="example-title"><span>Example 11</span>: Vocabulary base IRI</div><pre class="example">{
+ <span class="diff">"@context": {
+ "@vocab": "http://xmlns.com/foaf/1.0/"
+ },</span>
+ "@type": <span class="diff">"Person"</span>,
+ <span class="diff">"name"</span>: "Manu Sporny",
+}
+</pre>
+</div>
+<p>
+An
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+generated
+when
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+used
+in
+the
+value
+position
+that
+contains
+an
+<code>
+@id
+</code>
+keyword:
+</p>
+<div class="example"><div class="example-title"><span>Example 12</span>: Expanded IRI definition</div><pre class="example">{
+...
+ "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
+...
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+Specifying
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+with
+an
+<code>
+@id
+</code>
+key
+is
+used
+to
+identify
+that
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>
+using
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+When
+the
+object
+has
+only
+the
+<code>
+@id
+</code>,
+it
+is
+called
+a
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>.
+This
+facility
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+to
+link
+to
+another
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+using
+a
+mechanism
+called
+<a class="tref internalDFN" title="embedding" href="#dfn-embedding">
+embedding
+</a>,
+which
+is
+covered
+in
+the
+section
+titled
+<a href="#embedding" class="sec-ref">
+<span class="secno">
+4.10
+</span>
+<span class="sec-title">
+Embedding
+</span>
+</a>.
+</p>
+</div>
+<p>
+If
+type
+<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
+coercion
+</a>
+rules
+are
+specified
+in
+the
+<code>
+@context
+</code>
+for
+a
+particular
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+or
+property
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>,
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+generated:
+</p>
+<div class="example"><div class="example-title"><span>Example 13</span>: Type coercion</div><pre class="example">{<span class="diff">
+ "@context":
+ {
+ ...
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ ...
+ }</span>
+...
+ "homepage": "http://manu.sporny.org/",
+...
+}
+</pre>
+</div>
+<p>
+In
+the
+example
+above,
+even
+though
+the
+value
+<code>
+http://manu.sporny.org/
+</code>
+is
+expressed
+as
+a
+JSON
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+the
+type
+<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
+coercion
+</a>
+rules
+will
+transform
+the
+value
+into
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+when
+processed
+by
+a
+JSON-LD
+Processor.
+</p>
+</section>
+<section id="node-identifiers">
+<h3>
+<span class="secno">
+<del class="diff-old">3.6
+</del>
+<ins class="diff-chg">3.8
+</ins>
+</span>
+Node
+Identifiers
+</h3>
+<p>
+To
+be
+able
+to
+externally
+reference
+nodes
+in
+a
+graph,
+it
+is
+important
+that
+each
+node
+has
+an
+unambiguous
+identifier.
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+are
+a
+fundamental
+concept
+of
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>,
+and
+nodes
+should
+have
+a
+de-referencable
+identifier
+used
+to
+name
+and
+locate
+them.
+For
+nodes
+to
+be
+truly
+linked,
+de-referencing
+the
+identifier
+should
+result
+in
+a
+representation
+of
+that
+node
+(for
+example,
+using
+a
+URL
+to
+retrieve
+a
+web
+page).
+Associating
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+with
+a
+node
+tells
+an
+application
+that
+the
+returned
+document
+contains
+a
+description
+of
+the
+node
+requested.
+</p>
+<p>
+JSON-LD
+documents
+may
+also
+contain
+descriptions
+of
+other
+nodes,
+so
+it
+is
+necessary
+to
+be
+able
+to
+uniquely
+identify
+each
+node
+which
+may
+be
+externally
+referenced.
+</p>
+<p>
+The
+node
+of
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+identified
+using
+the
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 14</span>: Identifying a node</div><pre class="example">{
+ "@context":
+ {
+ ...
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ ...
+ },
+ "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
+ "homepage": "http://manu.sporny.org/",
+...
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+contains
+a
+node
+identified
+by
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://example.org/people#joebob
+</code>.
+</p>
+<p>
+A
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+used
+to
+define
+property
+values
+is
+called
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>.
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+Node
+definitions
+</a>
+do
+not
+require
+an
+<code>
+@id
+</code>.
+A
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+that
+does
+not
+contain
+an
+<code>
+@id
+</code>
+property
+defines
+properties
+of
+an
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>.
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+Node
+definitions
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+be
+spread
+among
+different
+parts
+of
+a
+document
+or
+even
+between
+different
+documents.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+To
+ensure
+the
+best
+possible
+performance,
+when
+possible,
+it
+is
+a
+best
+practice
+to
+put
+JSON-LD
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+s,
+such
+as
+<code>
+@id
+</code>
+and
+<code>
+@context
+</code>
+before
+other
+key-value
+pairs
+in
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>.
+However,
+keys
+in
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+are
+not
+ordered,
+so
+processors
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+depend
+on
+key
+ordering.
+If
+keywords
+are
+not
+listed
+first,
+processors
+have
+to
+save
+each
+key-value
+pair
+until
+at
+least
+the
+<code>
+@context
+</code>
+and
+the
+<code>
+@id
+</code>
+are
+processed.
+Not
+specifying
+those
+keywords
+first
+creates
+a
+memory
+and
+complexity
+burden
+for
+low-memory
+footprint
+processors,
+forcing
+them
+to
+use
+more
+memory
+and
+computing
+cycles
+than
+necessary.
+</p>
+</div>
+</section>
+<section id="specifying-the-type">
+<h3>
+<span class="secno">
+<del class="diff-old">3.7
+</del>
+<ins class="diff-chg">3.9
+</ins>
+</span>
+Specifying
+the
+Type
+</h3>
+<p>
+The
+type
+of
+a
+particular
+node
+can
+be
+specified
+using
+the
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+To
+be
+considered
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>,
+types
+<em class="rfc2119" title="must">
+must
+</em>
+be
+uniquely
+identified
+by
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 15</span>: Specifying the type for a node</div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "<span class="diff">@type</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+...
+}
+</pre>
+</div>
+<p>
+A
+node
+can
+be
+assigned
+more
+than
+one
+type
+by
+using
+the
+following
+markup
+pattern:
+</p>
+<div class="example"><div class="example-title"><span>Example 16</span>: Specifying multiple types for a node</div><pre class="example">{
+...
+ "@id": "http://example.org/places#BrewEats",
+ "<span class="diff">@type</span>": <span class="diff">["http://schema.org/Restaurant", "http://schema.org/Brewery"]</span>
+...
+}
+</pre>
+</div>
+</section>
+<section id="string-internationalization">
+<h3>
+<span class="secno">
+<del class="diff-old">3.8
+</del>
+<ins class="diff-chg">3.10
+</ins>
+</span>
+String
+Internationalization
+</h3>
+<p>
+At
+times,
+it
+is
+important
+to
+annotate
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+with
+its
+language.
+In
+JSON-LD
+this
+is
+possible
+in
+a
+variety
+of
+ways.
+Firstly,
+it
+is
+possible
+to
+define
+a
+default
+language
+for
+a
+JSON-LD
+document
+by
+setting
+the
+<code>
+@language
+</code>
+key
+in
+the
+<code>
+@context
+</code>
+or
+in
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+definition:
+</p>
+<div class="example"><div class="example-title"><span>Example 17</span>: String Internationalization</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ ...
+ "@language": "ja"
+ },</span>
+ "name": <span class="diff">"花澄"</span>,
+ "occupation": <span class="diff">"科学者"</span>
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+would
+associate
+the
+<code>
+ja
+</code>
+language
+code
+with
+the
+two
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+s
+<em>
+花澄
+</em>
+and
+<em>
+科学者
+</em>.
+Languages
+<em class="rfc2119" title="must">
+must
+</em>
+be
+well-formed
+language
+tags
+according
+to
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+].
+</p>
+<p>
+It
+is
+possible
+to
+override
+the
+default
+language
+by
+using
+the
+expanded
+form
+of
+a
+value:
+</p>
+<div class="example"><div class="example-title"><span>Example 18</span>: Expanded value with language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": "花澄",
+ "occupation": <span class="diff">{
+ "@value": "Scientist",
+ "@language": "en"
+ }</span>
+}
+</pre>
+</div>
+<p>
+It
+is
+also
+possible
+to
+override
+the
+default
+language
+or
+specify
+a
+plain
+value
+by
+omitting
+the
+<code>
+@language
+</code>
+tag
+or
+setting
+it
+to
+<code>
+null
+</code>
+when
+expressing
+the
+expanded
+value:
+</p>
+<div class="example"><div class="example-title"><span>Example 19</span>: Expanded value to remove language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": <span class="diff">{
+ "@value": "Frank"
+ },</span>
+ "occupation": <span class="diff"> {
+ "@value": "Ninja",
+ "@language": "en"
+ }</span>,
+ "speciality": "手裏剣"
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+Please
+note
+that
+language
+associations
+<em class="rfc2119" title="must">
+must
+</em>
+only
+be
+applied
+to
+plain
+literal
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+s.
+That
+is,
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>
+s
+or
+values
+that
+are
+subject
+to
+<a href="#type-coercion" class="sec-ref">
+<span class="secno">
+4.6
+</span>
+<span class="sec-title">
+Type
+Coercion
+</span>
+</a>
+won't
+be
+language
+tagged.
+</p>
+</div>
+<p>
+To
+clear
+the
+default
+language
+for
+a
+subtree,
+<code>
+@language
+</code>
+can
+be
+set
+to
+<code>
+null
+</code>
+in
+a
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+as
+follows:
+</p>
+<div class="example"><div class="example-title"><span>Example 20</span>: Clearing default language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": "花澄",
+ "details": {
+<span class="diff"> "@context": {
+ "@language": null
+ },</span>
+ "occupation": "Ninja"
+ }
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+JSON-LD
+allows
+one
+to
+associate
+language
+information
+with
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s.
+See
+<a href="#expanded-term-definition" class="sec-ref">
+<span class="secno">
+4.5
+</span>
+<span class="sec-title">
+Expanded
+Term
+Definition
+</span>
+</a>
+for
+more
+details.
+</p>
+</div>
+</section>
+<section id="json-ld-syntax">
+<h3>
+<span class="secno">
+<del class="diff-old">3.9
+</del>
+<ins class="diff-chg">3.11
+</ins>
+</span>
+JSON-LD
+Syntax
+</h3>
+<p>
+A
+JSON-LD
+document
+is
+first,
+and
+foremost,
+a
+JSON
+document
+(as
+defined
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+]),
+and
+any
+syntactically
+correct
+JSON
+document
+<em class="rfc2119" title="must">
+must
+</em>
+be
+processed
+by
+a
+conforming
+JSON-LD
+processor.
+However,
+JSON-LD
+describes
+a
+specific
+syntax
+to
+use
+for
+expressing
+Linked
+Data.
+This
+includes
+the
+use
+of
+specific
+keywords,
+as
+identified
+in
+<a href="#syntax-tokens-and-keywords" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.2
+</del>
+<ins class="diff-chg">3.4
+</ins>
+</span>
+<span class="sec-title">
+Syntax
+Tokens
+and
+Keywords
+</span>
+</a>
+for
+expressing
+<a title="node definition">
+node
+definitions
+</a>,
+values,
+and
+the
+<a href="#dfn-context" class="internalDFN">
+context
+</a>.
+See
+<a href="#json-ld-grammar" class="sec-ref">
+<span class="secno">
+A.
+</span>
+<span class="sec-title">
+JSON-LD
+Grammar
+</span>
+</a>
+for
+authoring
+guidelines
+and
+a
+BNF
+description
+of
+JSON-LD.
+</p>
+</section>
+</section>
+<section id="advanced-concepts">
+<h2>
+<span class="secno">
+4.
+</span>
+Advanced
+Concepts
+</h2>
+<em>
+This
+section
+is
+normative.
+</em>
+<p>
+JSON-LD
+has
+a
+number
+of
+features
+that
+provide
+functionality
+above
+and
+beyond
+the
+core
+functionality
+described
+above.
+The
+following
+section
+describes
+this
+advanced
+functionality
+in
+more
+detail.
+</p>
+<section id="compact-iris">
+<h3>
+<span class="secno">
+4.1
+</span>
+Compact
+IRIs
+</h3>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Term
+</a>
+s
+in
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+documents
+may
+draw
+from
+a
+number
+of
+different
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>.
+At
+times,
+declaring
+every
+single
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+that
+a
+document
+uses
+can
+require
+the
+developer
+to
+declare
+tens,
+if
+not
+hundreds
+of
+potential
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+that
+are
+used
+across
+an
+application.
+This
+is
+a
+concern
+for
+at
+least
+two
+reasons:
+the
+first
+is
+the
+cognitive
+load
+on
+the
+developer
+of
+remembering
+all
+of
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s,
+and
+the
+second
+is
+the
+serialized
+size
+of
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+if
+it
+is
+specified
+inline.
+In
+order
+to
+address
+these
+issues,
+the
+concept
+of
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+introduced.
+</p>
+<p>
+A
+<dfn title="compact_iri" id="dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+is
+a
+way
+of
+expressing
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+using
+a
+<em>
+prefix
+</em>
+and
+<em>
+suffix
+</em>
+separated
+by
+a
+colon
+(
+<code>:
+</code>
+)
+which
+is
+similar
+to
+the
+<cite>
+<a href="http://www.w3.org/TR/rdfa-core/#s_curies">
+CURIE
+Syntax
+</a>
+</cite>
+in
+[
+<cite>
+<a class="bibref" href="#bib-RDFA-CORE">
+RDFA-CORE
+</a>
+</cite>
+].
+The
+<dfn title="prefix" id="dfn-prefix">
+prefix
+</dfn>
+is
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+taken
+from
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+and
+is
+a
+short
+string
+identifying
+a
+particular
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+in
+a
+JSON-LD
+document.
+For
+example,
+the
+prefix
+<code>
+foaf
+</code>
+may
+be
+used
+as
+a
+short
+hand
+for
+the
+Friend-of-a-Friend
+vocabulary,
+which
+is
+identified
+using
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://xmlns.com/foaf/0.1/
+</code>.
+A
+developer
+may
+append
+any
+of
+the
+FOAF
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+terms
+to
+the
+end
+of
+the
+prefix
+to
+specify
+a
+short-hand
+version
+of
+the
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+for
+the
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+term.
+For
+example,
+<code>
+foaf:name
+</code>
+would
+be
+expanded
+out
+to
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>.
+Instead
+of
+having
+to
+remember
+and
+type
+out
+the
+entire
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>,
+the
+developer
+can
+instead
+use
+the
+prefix
+in
+their
+JSON-LD
+markup.
+</p>
+<p>
+Terms
+are
+interpreted
+as
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+if
+they
+contain
+at
+least
+one
+colon
+and
+the
+first
+colon
+is
+not
+followed
+by
+two
+slashes
+(
+<code>
+//
+</code>,
+as
+in
+<code>
+http://example.com
+</code>
+).
+To
+generate
+the
+full
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+the
+value
+is
+first
+split
+into
+a
+<em>
+prefix
+</em>
+and
+<em>
+suffix
+</em>
+at
+the
+first
+occurrence
+of
+a
+colon
+(
+<code>:
+</code>
+).
+If
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+contains
+a
+term
+mapping
+for
+<em>
+prefix
+</em>,
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+generated
+by
+prepending
+the
+mapped
+<em>
+prefix
+</em>
+to
+the
+(possibly
+empty)
+<em>
+suffix
+</em>
+using
+textual
+concatenation.
+If
+no
+prefix
+mapping
+is
+defined,
+the
+value
+is
+interpreted
+as
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+If
+the
+prefix
+is
+an
+underscore
+(
+<code>
+_
+</code>
+),
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+remains
+unchanged.
+This
+effectively
+means
+that
+every
+term
+containing
+a
+colon
+will
+be
+interpreted
+by
+a
+JSON-LD
+processor
+as
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>.
+</p>
+<p>
+Consider
+the
+following
+example:
+</p>
+ <div class="example"><div class="example-title"><span>Example 21</span>: Compact IRIs</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"dc": "http://purl.org/dc/elements/1.1/",</span>
+ <span class="diff">"ex": "http://example.org/vocab#"</span>
+ },
+ "@id": "http://example.org/library",
+ "@type": <span class="diff">"ex:Library"</span>,
+ <span class="diff">"ex:contains"</span>:
+ {
+ "@id": "http://example.org/library/the-republic",
+ "@type": <span class="diff">"ex:Book"</span>,
+ <span class="diff">"dc:creator"</span>: "Plato",
+ <span class="diff">"dc:title"</span>: "The Republic",
+ <span class="diff">"ex:contains"</span>:
+ {
+ "@id": "http://example.org/library/the-republic#introduction",
+ "@type": <span class="diff">"ex:Chapter"</span>,
+ <span class="diff">"dc:description"</span>: "An introductory chapter on The Republic.",
+ <span class="diff">"dc:title"</span>: "The Introduction"
+ }
+ }
+}
+</pre>
+</div>
+<p>
+In
+this
+example,
+two
+different
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+are
+referred
+to
+using
+prefixes.
+Those
+prefixes
+are
+then
+used
+as
+type
+and
+property
+values
+using
+the
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+prefix:suffix
+</code>
+notation.
+</p>
+<p>
+It's
+also
+possible
+to
+use
+compact
+IRIs
+within
+the
+context
+as
+shown
+in
+the
+following
+example:
+</p>
+ <div class="example"><div class="example-title"><span>Example 22</span>: Using vocabularies</div><pre class="example">{
+ "@context":
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ <span class="diff">"foaf:homepage"</span>: { "@type": "@id" },
+ "picture": { "@id": <span class="diff">"foaf:depiction"</span>, "@type": "@id" }
+ },
+ "@id": "http://me.markus-lanthaler.com/",
+ "@type": "foaf:Person",
+ "foaf:name": "Markus Lanthaler",
+ "foaf:homepage": "http://www.markus-lanthaler.com/",
+ "picture": "http://twitter.com/account/profile_image/markuslanthaler"
+}
+</pre>
+</div>
+</section>
+<section id="typed-values">
+<h3>
+<span class="secno">
+4.2
+</span>
+Typed
+Values
+</h3>
+<p>
+A
+value
+with
+an
+associated
+type,
+also
+known
+as
+a
+<dfn title="typed_value" id="dfn-typed_value">
+typed
+value
+</dfn>,
+is
+indicated
+by
+associating
+a
+value
+with
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+which
+indicates
+the
+value's
+type.
+Typed
+values
+may
+be
+expressed
+in
+JSON-LD
+in
+three
+ways:
+</p>
+<ol>
+<li>
+By
+utilizing
+the
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+when
+defining
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+within
+a
+<code>
+@context
+</code>
+section.
+</li>
+<li>
+By
+utilizing
+the
+expanded
+form
+for
+specifying
+values.
+</li>
+<li>
+By
+using
+a
+native
+JSON
+type
+such
+as
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>,
+<a class="tref internalDFN" title="true" href="#dfn-true">
+true
+</a>,
+or
+<a class="tref internalDFN" title="false" href="#dfn-false">
+false
+</a>.
+</li>
+</ol>
+<p>
+The
+first
+example
+uses
+the
+<code>
+@type
+</code>
+keyword
+to
+associate
+a
+type
+with
+a
+particular
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+in
+the
+<code>
+@context
+</code>:
+</p>
+<div class="example"><div class="example-title"><span>Example 23</span>: Expanded term definition with type coercion</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "modified":
+ {
+ "@id": "http://purl.org/dc/terms/modified",
+ "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
+ }
+ },</span>
+...
+ "modified": "2010-05-29T14:17:39+02:00",
+...
+}
+</pre>
+</div>
+<p>
+The
+<em>
+modified
+</em>
+key's
+value
+above
+is
+automatically
+type
+coerced
+to
+a
+datetime
+value
+because
+of
+the
+information
+specified
+in
+the
+<code>
+@context
+</code>.
+</p>
+<p>
+The
+second
+example
+uses
+the
+expanded
+form
+of
+setting
+the
+type
+information
+in
+the
+body
+of
+a
+JSON-LD
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 24</span>: Expanded value with type</div><pre class="example">{
+ "@context":
+ {
+ "modified":
+ {
+ "@id": "http://purl.org/dc/terms/modified"
+ }
+ },
+...
+ "modified":
+ <span class="diff">{
+ "@value": "2010-05-29T14:17:39+02:00",
+ "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
+ }</span>
+...
+}
+</pre>
+</div>
+<p>
+Both
+examples
+above
+would
+generate
+the
+value
+<code>
+2010-05-29T14:17:39+02:00
+</code>
+with
+the
+type
+<code>
+http://www.w3.org/2001/XMLSchema#dateTime
+</code>.
+Note
+that
+it
+is
+also
+possible
+to
+use
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+or
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+to
+express
+the
+value
+of
+a
+type.
+</p>
+<p>
+The
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+is
+also
+used
+to
+associate
+a
+type
+with
+a
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>.
+The
+concept
+of
+an
+<dfn title="node_type" id="dfn-node_type">
+node
+type
+</dfn>
+and
+a
+<dfn title="value_type" id="dfn-value_type">
+value
+type
+</dfn>
+are
+different.
+This
+is
+similar
+to
+object-oriented
+programming
+languages
+where
+both
+scalar
+and
+structured
+types
+use
+the
+same
+class
+inheritance
+mechanism,
+even
+though
+scalar
+types
+and
+structured
+types
+are
+inherently
+different.
+</p>
+<div class="example"><div class="example-title"><span>Example 25</span>: Example demonstrating the context-sensitivity for @type</div><pre class="example">{
+...
+ "@id": "http://example.org/posts#TripToWestVirginia",
+ <span class="diff">"@type": "http://schema.org/BlogPosting"</span>,
+ "modified":
+ {
+ "@value": "2010-05-29T14:17:39+02:00",
+ <span class="diff">"@type": "http://www.w3.org/2001/XMLSchema#dateTime"</span>
+ }
+...
+}
+</pre>
+</div>
+<p>
+The
+first
+use
+of
+<code>
+@type
+</code>
+associates
+a
+<a class="tref internalDFN" title="node_type" href="#dfn-node_type">
+node
+type
+</a>
+(
+<code>
+http://schema.org/BlogPosting
+</code>
+)
+with
+the
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>,
+which
+is
+expressed
+using
+the
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+The
+second
+use
+of
+<code>
+@type
+</code>
+associates
+a
+<a class="tref internalDFN" title="value_type" href="#dfn-value_type">
+value
+type
+</a>
+(
+<code>
+http://www.w3.org/2001/XMLSchema#dateTime
+</code>
+)
+with
+the
+value
+expressed
+using
+the
+<code>
+@value
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+As
+a
+general
+rule,
+when
+<code>
+@value
+</code>
+and
+<code>
+@type
+</code>
+are
+used
+in
+the
+same
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>,
+the
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+is
+expressing
+a
+<a class="tref internalDFN" title="value_type" href="#dfn-value_type">
+value
+type
+</a>.
+Otherwise,
+the
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+is
+expressing
+a
+<a class="tref internalDFN" title="node_type" href="#dfn-node_type">
+node
+type
+</a>.
+</p>
+</section>
+<section id="language-tagged-strings">
+<h3>
+<span class="secno">
+4.3
+</span>
+Language-tagged
+Strings
+</h3>
+<p>
+A
+string
+with
+an
+associated
+language,
+also
+known
+as
+a
+<dfn title="language-tagged_string" id="dfn-language-tagged_string">
+language-tagged
+string
+</dfn>,
+is
+indicated
+by
+associating
+a
+string
+with
+an
+language
+code
+as
+defined
+in
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+].
+Language-tagged
+strings
+may
+be
+expressed
+in
+JSON-LD
+in
+four
+ways:
+</p>
+<ol>
+<li>
+By
+defining
+a
+global
+language
+using
+the
+<code>
+@language
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+within
+a
+<code>
+@context
+</code>
+section.
+</li>
+<li>
+By
+utilizing
+the
+<code>
+@language
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+when
+defining
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+within
+a
+<code>
+@context
+</code>
+section.
+</li>
+<li>
+By
+utilizing
+the
+expanded
+form
+for
+specifying
+values.
+</li>
+<li>
+By
+utilizing
+the
+<code>
+@container
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+with
+a
+value
+of
+<code>
+@language
+</code>
+when
+defining
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+within
+a
+<code>
+@context
+</code>
+section.
+This
+usage
+pattern
+is
+called
+a
+<dfn title="language_map" id="dfn-language_map">
+language
+map
+</dfn>.
+</li>
+</ol>
+<p>
+The
+first
+example
+uses
+the
+<code>
+@language
+</code>
+keyword
+to
+associate
+a
+type
+with
+a
+particular
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+in
+the
+<code>
+@context
+</code>:
+</p>
+<div class="example"><div class="example-title"><span>Example 26</span>: Expanded term definition with language coercion</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title",
+ "@language": "en"
+ }
+ },</span>
+...
+ "title": "JSON-LD Syntax",
+...
+}
+</pre>
+</div>
+<p>
+The
+<em>
+modified
+</em>
+key's
+value
+above
+is
+automatically
+language
+coerced
+to
+a
+English
+value
+because
+of
+the
+information
+specified
+in
+the
+<code>
+@context
+</code>.
+</p>
+<p>
+The
+second
+example
+uses
+the
+expanded
+form
+of
+setting
+the
+language
+information
+in
+the
+body
+of
+a
+JSON-LD
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 27</span>: Expanded value with language</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "@value": "JSON-LD Syntax",
+ "@language": "en"
+ }</span>
+...
+}
+</pre>
+</div>
+<p>
+Both
+examples
+above
+would
+generate
+the
+value
+<code>
+JSON-LD
+Syntax
+</code>
+tagged
+with
+the
+language
+<code>
+en
+</code>
+;
+which
+is
+the
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+code
+for
+the
+English
+language.
+</p>
+<p>
+Systems
+that
+support
+multiple
+languages
+often
+need
+to
+express
+data
+values
+in
+each
+language.
+Typically,
+such
+systems
+also
+try
+to
+ensure
+that
+developers
+have
+a
+programatically
+easy
+way
+to
+navigate
+the
+datastructures
+for
+the
+language-specific
+data.
+In
+this
+case,
+<a class="tref internalDFN" title="language_map" href="#dfn-language_map">
+language
+map
+</a>
+s
+may
+be
+utilized.
+</p>
+<div class="example"><div class="example-title"><span>Example 28</span>: Language map expressing a property in three languages</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ "@container": "@language"
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "en": "JSON-LD Syntax",
+ "ru": "JSON-LD Синтаксис",
+ "ja": "JSON-LDの構文"
+ }</span>
+...
+}
+</pre>
+</div>
+<p>
+In
+the
+example
+above,
+the
+title
+is
+expressed
+in
+three
+languages;
+English,
+Russian,
+and
+Japanese.
+To
+access
+the
+data
+above
+in
+a
+programming
+language
+supporting
+dot-notation
+accessors
+for
+object
+properties,
+a
+developer
+may
+use
+the
+<code>
+property.language
+</code>
+pattern.
+For
+example,
+to
+access
+the
+Japanese
+version
+of
+the
+title,
+a
+developer
+would
+use
+the
+following
+code
+snippet:
+<code>
+obj.title.ja
+</code>.
+</p>
+</section>
+<section id="referencing-contexts-from-json-documents">
+<h3>
+<span class="secno">
+4.4
+</span>
+Referencing
+Contexts
+from
+JSON
+Documents
+</h3>
+<p>
+Ordinary
+JSON
+documents
+can
+be
+transformed
+into
+JSON-LD
+documents
+by
+referencing
+to
+an
+external
+JSON-LD
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+in
+an
+HTTP
+Link
+Header.
+Doing
+this
+allows
+JSON
+to
+be
+unambiguously
+machine-readable
+without
+requiring
+developers
+to
+drastically
+change
+their
+workflow
+and
+provides
+an
+upgrade
+path
+for
+existing
+infrastructure
+without
+breaking
+existing
+clients
+that
+rely
+on
+the
+<code>
+application/json
+</code>
+media
+type.
+</p>
+<p>
+In
+order
+to
+use
+an
+external
+context
+with
+an
+ordinary
+JSON
+document,
+an
+author
+<em class="rfc2119" title="must">
+must
+</em>
+specify
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+to
+a
+valid
+JSON-LD
+document
+in
+an
+HTTP
+Link
+Header
+[
+<cite>
+<a class="bibref" href="#bib-RFC5988">
+RFC5988
+</a>
+</cite>
+]
+using
+the
+<code>
+describedby
+</code>
+link
+relation.
+The
+referenced
+document
+<em class="rfc2119" title="must">
+must
+</em>
+have
+a
+top-level
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>.
+The
+<code>
+@context
+</code>
+subtree
+within
+that
+object
+is
+added
+to
+the
+top-level
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+of
+the
+referencing
+document.
+If
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+is
+at
+the
+top-level
+of
+the
+referencing
+document
+and
+its
+items
+are
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>,
+the
+<code>
+@context
+</code>
+subtree
+is
+added
+to
+all
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+items.
+All
+extra
+information
+located
+outside
+of
+the
+<code>
+@context
+</code>
+subtree
+in
+the
+referenced
+document
+<em class="rfc2119" title="must">
+must
+</em>
+be
+discarded.
+</p>
+<p>
+The
+following
+example
+demonstrates
+the
+use
+of
+an
+external
+context
+with
+an
+ordinary
+JSON
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 29</span>: Specifing context through HTTP header</div><pre class="example">GET /ordinary-json-document.json HTTP/1.1
+Host: example.com
+Accept: application/ld+json,application/json,*/*;q=0.1
+====================================
+HTTP/1.0 200 OK
+...
+Content-Type: <span class="diff">application/json</span>
+<span class="diff">Link: <http://json-ld.org/contexts/person.jsonld>; rel="describedby"; type="application/ld+json"</span>
+{
+ "name": "Markus Lanthaler",
+ "homepage": "http://www.markus-lanthaler.com/",
+ "depiction": "http://twitter.com/account/profile_image/markuslanthaler"
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+JSON-LD
+documents
+served
+with
+the
+<code>
+application/ld+json
+</code>
+media
+type
+<em class="rfc2119" title="must">
+must
+</em>
+have
+all
+context
+information,
+including
+references
+to
+external
+contexts,
+within
+the
+body
+of
+the
+document.
+</p>
+</div>
+</section>
+<section id="expanded-term-definition">
+<h3>
+<span class="secno">
+4.5
+</span>
+Expanded
+Term
+Definition
+</h3>
+<p>
+Within
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition,
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+<em class="rfc2119" title="may">
+may
+</em>
+be
+defined
+using
+an
+expanded
+notation
+to
+allow
+for
+additional
+information
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+to
+be
+specified
+(see
+also
+<a href="#type-coercion" class="sec-ref">
+<span class="secno">
+4.6
+</span>
+<span class="sec-title">
+Type
+Coercion
+</span>
+</a>
+and
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+).
+</p>
+<p>
+Instead
+of
+using
+a
+string
+representation
+of
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>,
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<em class="rfc2119" title="may">
+may
+</em>
+be
+specified
+using
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+having
+an
+<code>
+@id
+</code>
+key.
+The
+value
+of
+the
+<code>
+@id
+</code>
+key
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+Such
+an
+object
+is
+called
+a
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 30</span>: Expanded term definition</div><pre class="example">{
+ "@context":
+ {
+ "foaf": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/" }</span>,
+ "name": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/name" }</span>,
+ "homepage": <span class="diff">{ "@id": "foaf:homepage" }</span>,
+ "depiction": <span class="diff">{ "@id": "foaf:depiction" }</span>
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+This
+allows
+additional
+information
+to
+be
+associated
+with
+the
+term.
+This
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+for
+<a href="#type-coercion" class="sec-ref">
+<span class="secno">
+4.6
+</span>
+<span class="sec-title">
+Type
+Coercion
+</span>
+</a>,
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+),
+or
+to
+associate
+language
+information
+with
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+as
+shown
+in
+the
+following
+example:
+</p>
+<div class="example"><div class="example-title"><span>Example 31</span>: Expanded term definition with language</div><pre class="example">{
+ "@context": {
+ ...
+ "ex": "http://example.com/",
+ "@language": "ja",
+ "name": { "@id": "ex:name", <span class="diff">"@language": null</span> },
+ "occupation": { "@id": "ex:occupation" },
+ "occupation_en": { "@id": "ex:occupation", <span class="diff">"@language": "en"</span> },
+ "occupation_cs": { "@id": "ex:occupation", <span class="diff">"@language": "cs"</span> }
+ },
+ <span class="diff">"name": "Yagyū Muneyoshi",
+ "occupation": "忍者",
+ "occupation_en": "Ninja",
+ "occupation_cs": "Nindža",</span>
+ ...
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+would
+associate
+<em>
+忍者
+</em>
+with
+the
+specified
+default
+language
+code
+<code>
+ja
+</code>,
+<em>
+Ninja
+</em>
+with
+the
+language
+code
+<code>
+en
+</code>,
+and
+<em>
+Nindža
+</em>
+with
+the
+language
+code
+<code>
+cs
+</code>.
+The
+value
+of
+<code>
+name
+</code>,
+<em>
+Yagyū
+Muneyoshi
+</em>
+wouldn't
+be
+associated
+with
+any
+language
+code
+since
+<code>
+@language
+</code>
+was
+reset
+to
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>
+in
+the
+expanded
+term
+definition.
+</p>
+<p>
+Expanded
+terms
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+defined
+using
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+IRIs
+</a>
+or
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+IRIs
+</a>
+as
+keys.
+If
+the
+definition
+does
+not
+include
+an
+<code>
+@id
+</code>
+key,
+the
+expanded
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+determined
+by
+performing
+expansion
+of
+the
+key
+within
+the
+current
+active
+context.
+This
+mechanism
+is
+mainly
+used
+to
+associate
+type
+or
+language
+information
+with
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+While
+it
+is
+possible
+to
+define
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+an
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+to
+expand
+to
+some
+other
+unrelated
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+(for
+example,
+<code>
+foaf:name
+</code>
+expanding
+to
+<code>
+http://example.org/unrelated#species
+</code>
+),
+such
+usage
+is
+strongly
+discouraged.
+</p>
+</div>
+</section>
+<section id="type-coercion">
+<h3>
+<span class="secno">
+4.6
+</span>
+Type
+Coercion
+</h3>
+<p>
+JSON-LD
+supports
+the
+coercion
+of
+values
+to
+particular
+data
+types.
+Type
+<dfn title="coercion" id="dfn-coercion">
+coercion
+</dfn>
+allows
+someone
+deploying
+JSON-LD
+to
+coerce
+the
+incoming
+or
+outgoing
+values
+to
+the
+proper
+data
+type
+based
+on
+a
+mapping
+of
+data
+type
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+to
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s.
+Using
+type
+coercion,
+value
+representation
+is
+preserved
+without
+requiring
+the
+data
+type
+to
+be
+specified
+with
+each
+piece
+of
+data.
+</p>
+<p>
+Type
+coercion
+is
+specified
+within
+an
+<a href="#expanded-term-definition" class="sec-ref">
+<span class="secno">
+4.5
+</span>
+<span class="sec-title">
+Expanded
+Term
+Definition
+</span>
+</a>
+using
+the
+<code>
+@type
+</code>
+key.
+The
+value
+of
+this
+key
+represents
+a
+type
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+and
+<em class="rfc2119" title="must">
+must
+</em>
+take
+the
+form
+of
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+the
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+<code>
+@id
+</code>.
+Specifying
+<code>
+@id
+</code>
+indicates
+that
+within
+the
+body
+of
+a
+JSON-LD
+document,
+a
+string
+value
+of
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+coerced
+to
+<code>
+@id
+</code>
+is
+to
+be
+interpreted
+as
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Terms
+</a>
+or
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+IRIs
+</a>
+used
+as
+the
+value
+of
+a
+<code>
+@type
+</code>
+key
+<em class="rfc2119" title="may">
+may
+</em>
+be
+defined
+within
+the
+same
+context.
+This
+means
+that
+one
+may
+specify
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+like
+<code>
+xsd
+</code>
+and
+then
+use
+<code>
+xsd:integer
+</code>
+within
+the
+same
+context
+definition
+-
+the
+JSON-LD
+processor
+will
+be
+able
+to
+determine
+the
+proper
+expansion
+for
+<code>
+xsd:integer
+</code>.
+</p>
+<p>
+The
+example
+below
+demonstrates
+how
+a
+JSON-LD
+author
+can
+coerce
+values
+to
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>
+s,
+IRIs
+and
+lists.
+</p>
+<div class="example"><div class="example-title"><span>Example 32</span>: Expanded term definition with types</div><pre class="example">{
+ "@context":
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age":
+ <span class="diff">{
+ "@id": "http://xmlns.com/foaf/0.1/age",
+ "@type": "xsd:integer"
+ }</span>,
+ "homepage":
+ <span class="diff">{
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id",
+ "@container": "@list"
+ }</span>
+ },
+ "name": "John Smith",
+ "age": <span class="diff">"41"</span>,
+ "homepage":
+ <span class="diff">[
+ "http://personal.example.org/",
+ "http://work.example.com/jsmith/"
+ ]</span>
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+Turtle:
+</p>
+<div class="example"><div class="example-title"><span>Example 33</span></div><pre class="example">@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+[ foaf:name "John Smith";
+ foaf:age "41"^^xsd:integer;
+ foaf:homepage ( <http://personal.example.org/> <http://work.example.com/jsmith/> )
+]
+.
+</pre>
+</div>
+<p>
+Terms
+may
+also
+be
+defined
+using
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+IRIs
+</a>
+or
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+IRIs
+</a>.
+This
+allows
+coercion
+rules
+to
+be
+applied
+to
+keys
+which
+are
+not
+represented
+as
+a
+simple
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>.
+For
+example:
+</p>
+<div class="example"><div class="example-title"><span>Example 34</span>: Term definition with absolute IRI</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "<span class="diff">foaf:age</span>":
+ {
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">foaf:homepage</span>":
+ <span class="diff">{
+ "@type": "@id"
+ }</span>
+ },
+ "foaf:name": "John Smith",
+ "foaf:age": <span class="diff">"41"</span>,
+ "foaf:homepage":
+ <span class="diff">[
+ "http://personal.example.org/",
+ "http://work.example.com/jsmith/"
+ ]</span>
+}
+</pre>
+</div>
+<p>
+In
+this
+case
+the
+<code>
+@id
+</code>
+definition
+is
+optional,
+but
+if
+it
+does
+exist,
+the
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+treated
+as
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+(not
+a
+<code>
+prefix:suffix
+</code>
+construct)
+so
+that
+the
+actual
+definition
+of
+a
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+becomes
+unnecessary.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+Keys
+in
+the
+context
+are
+treated
+as
+<a class="tref internalDFN" title="term" href="#dfn-term">
+terms
+</a>
+for
+the
+purpose
+of
+expansion
+and
+value
+coercion.
+At
+times,
+this
+may
+result
+in
+multiple
+representations
+for
+the
+same
+expanded
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>.
+For
+example,
+one
+could
+specify
+that
+<code>
+dog
+</code>
+and
+<code>
+cat
+</code>
+both
+expanded
+to
+<code>
+http://example.com/vocab#animal
+</code>.
+Doing
+this
+could
+be
+useful
+for
+establishing
+different
+type
+coercion
+or
+language
+specification
+rules.
+It
+also
+allows
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(or
+even
+an
+absolute
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+)
+to
+be
+defined
+as
+something
+else
+entirely.
+For
+example,
+one
+could
+specify
+that
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+<code>
+http://example.org/zoo
+</code>
+should
+expand
+to
+<code>
+http://example.org/river
+</code>,
+but
+this
+usage
+is
+discouraged
+because
+it
+would
+lead
+to
+a
+great
+deal
+of
+confusion
+among
+developers
+attempting
+to
+understand
+the
+JSON-LD
+document.
+</p>
+</div>
+<p>
+Type
+coercion
+is
+performed
+using
+the
+unexpanded
+value
+of
+the
+key,
+which
+<em class="rfc2119" title="must">
+must
+</em>
+have
+an
+exact
+match
+for
+an
+entry
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+</p>
+</section>
+<section id="property-generators">
+<h3>
+<span class="secno">
+4.7
+</span>
+Property
+Generators
+</h3>
+<p>
+At
+times,
+an
+author
+may
+find
+that
+they
+need
+to
+express
+the
+same
+value
+for
+multiple
+properties.
+The
+simplest
+approach
+to
+accomplish
+this
+goal
+would
+be
+to
+do
+the
+following:
+</p>
+<div class="example"><div class="example-title"><span>Example 35</span>: Verbose expression of multiple properties with the same value</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"title1": "http://purl.org/dc/terms/title"</span>,
+ <span class="diff">"title2": "http://schema.org/name"</span>,
+ <span class="diff">"title3": "http://www.w3.org/2000/01/rdf-schema#label"</span>
+ },
+ "@id": "http://example.com/book",
+ <span class="diff">"title1": "The Count of Monte Cristo"</span>,
+ <span class="diff">"title2": "The Count of Monte Cristo"</span>,
+ <span class="diff">"title3": "The Count of Monte Cristo"</span>
+}
+</pre>
+</div>
+<p>
+Unfortunately,
+the
+approach
+above
+produces
+redundant
+data
+and
+would
+become
+a
+publishing
+burden
+for
+large
+data
+sets.
+In
+these
+situations,
+the
+author
+may
+use
+a
+<dfn title="property_generator" id="dfn-property_generator">
+property
+generator
+</dfn>
+to
+express
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+once,
+but
+have
+the
+JSON-LD
+processor
+expand
+the
+single
+statement
+into
+multiple
+statements.
+This
+method
+can
+be
+accomplished
+by
+using
+the
+following
+markup
+pattern:
+</p>
+<div class="example"><div class="example-title"><span>Example 36</span>: Generating multiple properties using a single term</div><pre class="example">{
+ "@context":
+ {
+<del class="diff-old"> "title": { "@id": ["http://purl.org/dc/terms/title",
+ "http://schema.org/name",
+ "http://www.w3.org/2000/01/rdf-schema#label"] },
+</del>
+ <span class="diff">"title": { "@id": [ "http://purl.org/dc/terms/title",
+<ins class="diff-chg"> "http://schema.org/name",
+ "http://www.w3.org/2000/01/rdf-schema#label" ] }</span>
+</ins>
+ },
+ "@id": "http://example.com/book",
+ <span class="diff">"title": "The Count of Monte Cristo"</span>
+}
+</pre>
+</div>
+<p>
+While
+the
+term
+above
+is
+only
+used
+once
+outside
+of
+the
+<code>
+@context
+</code>,
+a
+JSON-LD
+processor
+will
+internally
+transform
+the
+document
+above
+into
+the
+following
+set
+of
+statements:
+</p>
+<div class="example"><div class="example-title"><span>Example 37</span></div><pre class="example"><http://example.com/book>
+ <http://purl.org/dc/terms/title>
+ "The Count of Monte Cristo" .
+<http://example.com/book>
+ <http://schema.org/name>
+ "The Count of Monte Cristo" .
+<http://example.com/book>
+ <http://www.w3.org/2000/01/rdf-schema#label>
+"The
+Count
+of
+Monte
+Cristo"
+.
+</pre>
+</div>
+</section>
+<section id="iri-expansion-within-a-context">
+<h3>
+<span class="secno">
+4.8
+</span>
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+Expansion
+Within
+a
+Context
+</h3>
+<p>
+In
+general,
+normal
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+expansion
+rules
+apply
+anywhere
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+expected
+(see
+<a href="#iris" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.5
+</del>
+<ins class="diff-chg">3.7
+</ins>
+</span>
+<span class="sec-title">
+IRIs
+</span>
+</a>
+).
+Within
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition,
+this
+can
+mean
+that
+terms
+defined
+within
+the
+context
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+within
+that
+context
+as
+long
+as
+there
+are
+no
+circular
+dependencies.
+For
+example,
+it
+is
+common
+to
+use
+the
+<code>
+xsd
+</code>
+namespace
+when
+defining
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>
+s:
+</p>
+<div class="example"><div class="example-title"><span>Example 38</span>: IRI expansion within context</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"xsd": "http://www.w3.org/2001/XMLSchema#"</span>,
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/age",
+ "@type": <span class="diff">"xsd:integer"</span>
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ ...
+}
+</pre>
+</div>
+<p>
+In
+this
+example,
+the
+<code>
+xsd
+</code>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+is
+defined
+and
+used
+as
+a
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+for
+the
+<code>
+@type
+</code>
+coercion
+of
+the
+<code>
+age
+</code>
+property.
+</p>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Term
+</a>
+s
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+when
+defining
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+of
+another
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 39</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": <span class="diff">"foaf:name"</span>,
+ "age":
+ {
+ "@id": <span class="diff">"foaf:age"</span>,
+ "@type": "xsd:integer"
+ },
+ "homepage":
+ {
+ "@id": <span class="diff">"foaf:homepage"</span>,
+ "@type": "@id"
+ }
+ },
+ ...
+}
+</pre>
+</div>
+<p>
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+Compact
+IRIs
+</a>
+and
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+IRIs
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+on
+the
+left-hand
+side
+of
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+definition.
+</p>
+<div class="example"><div class="example-title"><span>Example 40</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "foaf:name",
+ "<span class="diff">foaf:age</span>":
+ {
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">foaf:homepage</span>":
+ <span class="diff">{
+ "@type": "@id"
+ }</span>
+ },
+ ...
+}
+</pre>
+</div>
+<p>
+In
+this
+example,
+the
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+form
+is
+used
+in
+two
+different
+ways.
+In
+the
+first
+approach,
+<code>
+foaf:age
+</code>
+declares
+both
+the
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+for
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+(using
+short-form)
+as
+well
+as
+the
+<code>
+@type
+</code>
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>.
+In
+the
+second
+approach,
+only
+the
+<code>
+@type
+</code>
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+is
+specified.
+The
+JSON-LD
+processor
+will
+derive
+the
+full
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+for
+<code>
+foaf:homepage
+</code>
+by
+looking
+up
+the
+<code>
+foaf
+</code>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+</p>
+<p>
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+Absolute
+IRIs
+</a>
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+in
+the
+key
+position
+in
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 41</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "foaf:name",
+ "foaf:age":
+ {
+ "@id": "foaf:age",
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
+ {
+ "@type": "@id"
+ }
+ },
+ ...
+}
+</pre>
+</div>
+<p>
+In
+order
+for
+the
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+to
+match
+above,
+the
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+<em class="rfc2119" title="must">
+must
+</em>
+also
+be
+used
+in
+the
+JSON-LD
+document.
+Also
+note
+that
+<code>
+foaf:homepage
+</code>
+will
+not
+use
+the
+<code>
+{
+"@type":
+"@id"
+}
+</code>
+declaration
+because
+<code>
+foaf:homepage
+</code>
+is
+not
+the
+same
+as
+<code>
+http://xmlns.com/foaf/0.1/homepage
+</code>.
+That
+is,
+a
+JSON-LD
+processor
+will
+use
+direct
+string
+comparison
+when
+looking
+up
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+in
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+before
+it
+applies
+the
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+lookup
+mechanism.
+</p>
+<p>
+The
+only
+exception
+for
+using
+terms
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+is
+that
+they
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+be
+used
+in
+a
+circular
+manner.
+That
+is,
+a
+definition
+of
+<em>
+term-1
+</em>
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+depend
+on
+the
+definition
+of
+<em>
+term-2
+</em>
+if
+<em>
+term-2
+</em>
+also
+depends
+on
+<em>
+term-1
+</em>.
+For
+example,
+the
+following
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition
+is
+illegal:
+</p>
+<div class="example"><div class="example-title"><span>Example 42</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"term1": "term2:foo",
+ "term2": "term1:bar"</span>
+ },
+ ...
+}
+</pre>
+</div>
+</section>
+<section id="sets-and-lists">
+<h3>
+<span class="secno">
+4.9
+</span>
+Sets
+and
+Lists
+</h3>
+<p>
+A
+JSON-LD
+author
+can
+express
+multiple
+values
+in
+a
+compact
+way
+by
+using
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+s.
+Since
+graphs
+do
+not
+describe
+ordering
+for
+links
+between
+nodes,
+arrays
+in
+JSON-LD
+do
+not
+provide
+an
+ordering
+of
+the
+contained
+elements
+by
+default.
+This
+is
+exactly
+the
+opposite
+from
+regular
+JSON
+arrays,
+which
+are
+ordered
+by
+default.
+For
+example,
+consider
+the
+following
+simple
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 43</span></div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}
+</pre>
+</div>
+<p>
+The
+markup
+shown
+above
+would
+result
+in
+three
+triples
+being
+generated,
+each
+relating
+the
+node
+to
+an
+individual
+value,
+with
+no
+inherent
+order:
+</p>
+<div class="issue">
+<div class="issue-title">
+<span>
+Issue
+</span>
+</div>
+<p class="">
+Including
+an
+illustration
+might
+be
+better.
+</p>
+</div>
+<div class="example"><div class="example-title"><span>Example 44</span></div><pre class="example"><http://example.org/people#joebob> <http://xmlns.com/foaf/0.1/nick> "joe" .
+<http://example.org/people#joebob> <http://xmlns.com/foaf/0.1/nick> "bob" .
+<http://example.org/people#joebob>
+<http://xmlns.com/foaf/0.1/nick>
+"jaybee"
+.
+</pre>
+</div>
+<p>
+Multiple
+values
+may
+also
+be
+expressed
+using
+the
+expanded
+form:
+</p>
+<div class="example"><div class="example-title"><span>Example 45</span></div><pre class="example">{
+ "@id": "http://example.org/articles/8",
+ "dc:title": <span class="diff">
+ [
+ {
+ "@value": "Das Kapital",
+ "@language": "de"
+ },
+ {
+ "@value": "Capital",
+ "@language": "en"
+ }
+ ]</span>
+}
+</pre>
+</div>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples,
+again
+with
+no
+inherent
+order:
+</p>
+<div class="issue">
+<div class="issue-title">
+<span>
+Issue
+</span>
+</div>
+<p class="">
+Including
+an
+illustration
+might
+be
+better.
+</p>
+</div>
+<div class="example"><div class="example-title"><span>Example 46</span></div><pre class="example"><http://example.org/articles/8> <http://purl.org/dc/terms/title> "Das Kapital"@de .
+<http://example.org/articles/8>
+<http://purl.org/dc/terms/title>
+"Capital"@en
+.
+</pre>
+</div>
+<p>
+As
+the
+notion
+of
+ordered
+collections
+is
+rather
+important
+in
+data
+modeling,
+it
+is
+useful
+to
+have
+specific
+language
+support.
+In
+JSON-LD,
+a
+list
+may
+be
+represented
+using
+the
+<code>
+@list
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+as
+follows:
+</p>
+<div class="example"><div class="example-title"><span>Example 47</span></div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "foaf:nick":
+ <span class="diff">{
+ "@list": [ "joe", "bob", "jaybee" ]
+ }</span>,
+...
+}
+</pre>
+</div>
+<p>
+This
+describes
+the
+use
+of
+this
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+as
+being
+ordered,
+and
+order
+is
+maintained
+when
+processing
+a
+document.
+If
+every
+use
+of
+a
+given
+multi-valued
+property
+is
+a
+list,
+this
+may
+be
+abbreviated
+by
+setting
+<code>
+@container
+</code>
+to
+<code>
+@list
+</code>
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>:
+</p>
+<div class="example"><div class="example-title"><span>Example 48</span></div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ ...
+ "nick":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/nick",
+ "@container": "@list"
+ }
+ }</span>,
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+List
+of
+lists
+are
+not
+allowed
+in
+this
+version
+of
+JSON-LD.
+If
+a
+list
+of
+lists
+is
+detected,
+a
+JSON-LD
+processor
+will
+throw
+an
+exception.
+This
+decision
+was
+made
+due
+to
+the
+extreme
+amount
+of
+added
+complexity
+when
+processing
+lists
+of
+lists.
+</p>
+</div>
+<p>
+Similarly
+to
+<code>
+@list
+</code>,
+there
+exists
+the
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+<code>
+@set
+</code>
+to
+describe
+unordered
+sets.
+While
+its
+use
+in
+the
+body
+of
+a
+JSON-LD
+document
+represents
+just
+syntactic
+sugar
+that
+<em class="rfc2119" title="must">
+must
+</em>
+be
+optimized
+away
+when
+processing
+the
+document,
+it
+is
+very
+helpful
+when
+used
+within
+the
+context
+of
+a
+document.
+Values
+of
+terms
+associated
+with
+a
+<code>
+@set
+</code>
+or
+<code>
+@list
+</code>
+container
+are
+always
+represented
+in
+the
+form
+of
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+-
+even
+if
+there
+is
+just
+a
+single
+value
+that
+would
+otherwise
+be
+optimized
+to
+a
+non-array
+form
+in
+a
+<a href="#compact-document-form" class="sec-ref">
+<span class="secno">
+4.15
+</span>
+<span class="sec-title">
+Compact
+Document
+Form
+</span>
+</a>.
+This
+makes
+post-processing
+of
+the
+data
+easier
+as
+the
+data
+is
+always
+in
+array
+form,
+even
+if
+the
+array
+only
+contains
+a
+single
+value.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+The
+use
+of
+<code>
+@container
+</code>
+in
+the
+body
+of
+a
+JSON-LD
+document,
+i.e.,
+outside
+<code>
+@context
+</code>
+<em class="rfc2119" title="must">
+must
+</em>
+be
+ignored
+by
+JSON-LD
+processors.
+</p>
+</div>
+</section>
+<section id="embedding">
+<h3>
+<span class="secno">
+4.10
+</span>
+Embedding
+</h3>
+<p>
+<dfn title="embedding" id="dfn-embedding">
+Embedding
+</dfn>
+is
+a
+JSON-LD
+feature
+that
+allows
+an
+author
+to
+use
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>
+as
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>
+values.
+This
+is
+a
+commonly
+used
+mechanism
+for
+creating
+a
+parent-child
+relationship
+between
+two
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>
+s.
+</p>
+<p>
+The
+example
+shows
+two
+nodes
+related
+by
+a
+property
+from
+the
+first
+node:
+</p>
+ <div class="example"><div class="example-title"><span>Example 49</span></div><pre class="example">{
+...
+ "name": "Manu Sporny",
+ "<span class="diff">knows</span>":
+ {
+ "<span class="diff">@type</span>": "<span class="diff">Person</span>",
+ "<span class="diff">name</span>": "<span class="diff">Gregg Kellogg</span>",
+ }
+...
+}
+</pre>
+</div>
+<p>
+A
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+like
+the
+one
+used
+above,
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+in
+any
+value
+position
+in
+the
+body
+of
+a
+JSON-LD
+document.
+</p>
+</section>
+<section id="named-graphs">
+<h3>
+<span class="secno">
+4.11
+</span>
+Named
+Graphs
+</h3>
+<p>
+The
+<code>
+@graph
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+is
+used
+to
+express
+a
+set
+of
+JSON-LD
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+s
+that
+may
+not
+be
+directly
+related
+to
+one
+another
+through
+a
+property.
+The
+mechanism
+may
+also
+be
+used
+where
+<a class="tref internalDFN" title="embedding" href="#dfn-embedding">
+embedding
+</a>
+is
+not
+desirable
+to
+the
+application.
+For
+example:
+</p>
+ <div class="example"><div class="example-title"><span>Example 50</span></div><pre class="example">{
+ "@context": ...,
+ "<span class="diff">@graph</span>":
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}
+</pre>
+</div>
+<p>
+In
+this
+case,
+embedding
+doesn't
+work
+as
+each
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+references
+the
+other.
+Using
+the
+<code>
+@graph
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+allows
+multiple
+resources
+to
+be
+defined
+within
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>,
+and
+allows
+the
+use
+of
+a
+shared
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+When
+used
+in
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+that
+is
+not
+otherwise
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+this
+describes
+resources
+in
+the
+<em>
+default
+graph
+</em>.
+This
+is
+equivalent
+to
+using
+multiple
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>
+in
+array
+and
+defining
+the
+<code>
+@context
+</code>
+within
+each
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>:
+</p>
+ <div class="example"><div class="example-title"><span>Example 51</span></div><pre class="example"><span class="diff">[</span>
+ {
+ <span class="diff">"@context": ...,</span>
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ <span class="diff">"@context": ...,</span>
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+<span class="diff">
+]
+</span>
+</pre>
+</div>
+<p>
+JSON-LD
+allows
+you
+to
+<em>
+name
+</em>
+things
+on
+the
+Web
+by
+assigning
+an
+<code>
+@id
+</code>
+to
+them,
+which
+is
+typically
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+This
+notion
+extends
+to
+the
+ability
+to
+identify
+graphs
+in
+the
+same
+manner.
+A
+developer
+may
+name
+data
+expressed
+using
+the
+<code>
+@graph
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+by
+pairing
+it
+with
+an
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+This
+enables
+the
+developer
+to
+make
+statements
+about
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+itself,
+rather
+than
+just
+a
+single
+<a class="tref internalDFN" title="node" href="#dfn-node">
+node
+</a>.
+</p>
+ <div class="example"><div class="example-title"><span>Example 52</span></div><pre class="example">{
+ "@context": ...,
+ <span class="diff">"@id": "http://example.org/graphs/73",
+ "asOf": { "@value": "2012-04-09", "@type": "xsd:date" },
+ "@graph":</span>
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+expresses
+a
+<em>
+named
+</em>
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+that
+is
+identified
+by
+the
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+<code>
+http://example.org/graphs/73
+</code>.
+That
+graph
+is
+composed
+of
+the
+statements
+about
+Manu
+and
+Gregg.
+Meta-data
+about
+the
+graph
+itself
+is
+also
+expressed
+via
+the
+<code>
+asOf
+</code>
+property,
+which
+specifies
+when
+the
+information
+was
+retrieved
+from
+the
+Web.
+</p>
+<div class="issue">
+<div class="issue-title">
+<span>
+Issue
+</span>
+</div>
+<p class="">
+These
+examples
+could
+all
+have
+TriG
+definitions
+of
+their
+RDF
+results,
+but
+that
+would
+involve
+adding
+RDF
+earlier
+in
+the
+document.
+</p>
+</div>
+</section>
+<section id="identifying-unlabeled-nodes">
+<h3>
+<span class="secno">
+4.12
+</span>
+Identifying
+Unlabeled
+Nodes
+</h3>
+<p>
+At
+times,
+it
+becomes
+necessary
+to
+be
+able
+to
+express
+information
+without
+being
+able
+to
+specify
+the
+node.
+Typically,
+this
+type
+of
+node
+is
+called
+an
+<dfn title="unlabeled_node" id="dfn-unlabeled_node">
+unlabeled
+node
+</dfn>
+or
+a
+<dfn title="blank_node" id="dfn-blank_node">
+blank
+node
+</dfn>
+(see
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+]
+<cite>
+<a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">
+Section
+3.4:
+Blank
+Nodes
+</a>
+</cite>
+).
+In
+JSON-LD,
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>
+identifiers
+are
+automatically
+created
+if
+a
+node
+is
+not
+specified
+using
+the
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+However,
+authors
+may
+provide
+identifiers
+for
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+nodes
+</a>
+by
+using
+the
+special
+<code>
+_
+</code>
+(underscore)
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>.
+This
+allows
+one
+to
+reference
+the
+node
+locally
+within
+the
+document,
+but
+makes
+it
+impossible
+to
+reference
+the
+node
+from
+an
+external
+document.
+The
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>
+identifier
+is
+scoped
+to
+the
+document
+in
+which
+it
+is
+used.
+</p>
+<div class="example"><div class="example-title"><span>Example 53</span></div><pre class="example">{
+...
+ "@id": "<span class="diff">_:foo</span>",
+...
+}
+</pre>
+</div>
+<p>
+The
+example
+above
+would
+set
+the
+node
+to
+<code>
+_:foo
+</code>,
+which
+can
+then
+be
+used
+elsewhere
+in
+the
+JSON-LD
+document
+to
+refer
+back
+to
+the
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>.
+If
+a
+developer
+finds
+that
+they
+refer
+to
+the
+unlabeled
+node
+more
+than
+once,
+they
+should
+consider
+naming
+the
+node
+using
+a
+de-referenceable
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+so
+that
+it
+can
+be
+referenced
+also
+from
+other
+documents.
+</p>
+</section>
+<section id="aliasing-keywords">
+<h3>
+<span class="secno">
+4.13
+</span>
+Aliasing
+Keywords
+</h3>
+<p>
+Each
+of
+the
+JSON-LD
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>,
+except
+for
+<code>
+@context
+</code>,
+<em class="rfc2119" title="may">
+may
+</em>
+be
+aliased
+to
+application-specific
+keywords.
+This
+feature
+allows
+legacy
+JSON
+content
+to
+be
+utilized
+by
+JSON-LD
+by
+re-using
+JSON
+keys
+that
+already
+exist
+in
+legacy
+documents.
+This
+feature
+also
+allows
+developers
+to
+design
+domain-specific
+implementations
+using
+only
+the
+JSON-LD
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 54</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"url": "@id"</span>,
+ <span class="diff">"a": "@type"</span>,
+ "name": "http://schema.org/name"
+ },
+ "<span class="diff">url</span>": "http://example.com/about#gregg",
+ "<span class="diff">a</span>": "http://schema.org/Person",
+ "name": "Gregg Kellogg"
+}
+</pre>
+</div>
+<p>
+In
+the
+example
+above,
+the
+<code>
+@id
+</code>
+and
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>
+have
+been
+given
+the
+aliases
+<strong>
+url
+</strong>
+and
+<strong>
+a
+</strong>,
+respectively.
+</p>
+</section>
+<section id="expanded-document-form">
+<h3>
+<span class="secno">
+4.14
+</span>
+Expanded
+Document
+Form
+</h3>
+<p>
+The
+JSON-LD
+API
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+]
+defines
+an
+method
+for
+<em>
+expanding
+</em>
+a
+JSON-LD
+document.
+Expansion
+is
+the
+process
+of
+taking
+a
+JSON-LD
+document
+and
+applying
+a
+<code>
+@context
+</code>
+such
+that
+all
+IRIs,
+types,
+and
+values
+are
+expanded
+so
+that
+the
+<code>
+@context
+</code>
+is
+no
+longer
+necessary.
+</p>
+<p>
+For
+example,
+assume
+the
+following
+JSON-LD
+input
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 55</span></div><pre class="example">{
+ "@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+}
+</pre>
+</div>
+<p>
+Running
+the
+JSON-LD
+Expansion
+algorithm
+against
+the
+JSON-LD
+input
+document
+provided
+above
+would
+result
+in
+the
+following
+output:
+</p>
+<div class="example"><div class="example-title"><span>Example 56</span></div><pre class="example">[
+ {
+ "http://xmlns.com/foaf/0.1/name": [
+ { "@value": "Manu Sporny" }
+ ],
+ "http://xmlns.com/foaf/0.1/homepage": [
+ { "@id": "http://manu.sporny.org/" }
+ ]
+ }
+]
+</pre>
+</div>
+<p>
+Expanded
+document
+form
+is
+useful
+when
+an
+application
+has
+to
+process
+input
+data
+in
+a
+deterministic
+form.
+It
+has
+been
+optimized
+to
+ensure
+that
+the
+code
+that
+developers
+have
+to
+write
+is
+minimized
+compared
+to
+the
+code
+that
+would
+have
+to
+be
+written
+to
+operate
+on
+<a href="#compact-document-form" class="sec-ref">
+<span class="secno">
+4.15
+</span>
+<span class="sec-title">
+Compact
+Document
+Form
+</span>
+</a>.
+</p>
+</section>
+<section id="compact-document-form">
+<h3>
+<span class="secno">
+4.15
+</span>
+Compact
+Document
+Form
+</h3>
+<p>
+The
+JSON-LD
+API
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+]
+defines
+a
+method
+for
+<em>
+compacting
+</em>
+a
+JSON-LD
+document.
+Compaction
+is
+the
+process
+of
+taking
+a
+JSON-LD
+document
+and
+applying
+a
+context
+such
+that
+the
+most
+compact
+form
+of
+the
+document
+is
+generated.
+JSON
+is
+typically
+expressed
+in
+a
+very
+compact,
+key-value
+format.
+That
+is,
+full
+IRIs
+are
+rarely
+used
+as
+keys.
+At
+times,
+a
+JSON-LD
+document
+may
+be
+received
+that
+is
+not
+in
+its
+most
+compact
+form.
+JSON-LD,
+via
+the
+API,
+provides
+a
+way
+to
+compact
+a
+JSON-LD
+document.
+</p>
+<p>
+For
+example,
+assume
+the
+following
+JSON-LD
+input
+document:
+</p>
+<div class="example"><div class="example-title"><span>Example 57</span></div><pre class="example">[
+ {
+ "http://xmlns.com/foaf/0.1/name": [ "Manu Sporny" ],
+ "http://xmlns.com/foaf/0.1/homepage": [
+ {
+ "@id": "http://manu.sporny.org/"
+ }
+ ]
+ }
+]
+</pre>
+</div>
+<p>
+Additionally,
+assume
+the
+following
+developer-supplied
+JSON-LD
+context:
+</p>
+<div class="example"><div class="example-title"><span>Example 58</span></div><pre class="example">{
+ "@context": {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ }
+}
+</pre>
+</div>
+<p>
+Running
+the
+JSON-LD
+Compaction
+algorithm
+given
+the
+context
+supplied
+above
+against
+the
+JSON-LD
+input
+document
+provided
+above
+would
+result
+in
+the
+following
+output:
+</p>
+<div class="example"><div class="example-title"><span>Example 59</span></div><pre class="example">{
+ "@context": {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+}
+</pre>
+</div>
+<p>
+The
+compaction
+algorithm
+enables
+a
+developer
+to
+map
+any
+document
+into
+an
+application-specific
+compacted
+form
+by
+first
+<a href="#expanded-document-form" class="sec-ref">
+<span class="secno">
+4.14
+</span>
+<span class="sec-title">
+Expanded
+Document
+Form
+</span>
+</a>.
+While
+the
+context
+provided
+above
+mapped
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>
+to
+<strong>
+name
+</strong>,
+it
+could
+have
+also
+mapped
+it
+to
+any
+arbitrary
+string
+provided
+by
+the
+developer.
+This
+powerful
+mechanism,
+along
+with
+another
+JSON-LD
+API
+technique
+called
+<em>
+framing
+</em>,
+allows
+the
+developer
+to
+re-shape
+the
+incoming
+JSON
+data
+into
+a
+format
+that
+is
+optimized
+for
+their
+application.
+</p>
+</section>
+</section>
+<section class="appendix normative" id="json-ld-grammar">
+<h2>
+<span class="secno">
+A.
+</span>
+JSON-LD
+Grammar
+</h2>
+<em>
+This
+section
+is
+normative
+</em>
+<p class="issue resolved" data-number="114">
+This
+section
+is
+an
+attempt
+to
+formalize
+a
+normative
+grammar
+for
+JSON-LD.
+</p>
+<p>
+This
+appendix
+restates
+the
+syntactic
+conventions
+described
+in
+the
+previous
+sections
+more
+formally.
+</p>
+<p>
+A
+JSON-LD
+processor
+<em class="rfc2119" title="should">
+should
+</em>
+attempt
+to
+process
+non-conforming
+JSON-LD
+documents.
+Conformance
+violations
+<em class="rfc2119" title="must">
+must
+</em>
+be
+reported
+through
+a
+<ins class="diff-new">conformance
+violation
+</ins>
+callback
+mechanism
+defined
+in
+<ins class="diff-new">the
+</ins>
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+</p>
+<p>
+For
+a
+JSON-LD
+document
+to
+be
+conforming,
+it
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+valid
+JSON
+document
+as
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+].
+</p>
+<p>
+JSON-LD
+introduces
+a
+number
+of
+keywords
+of
+the
+form
+'
+<code>
+@
+</code>
+'
+followed
+by
+a
+set
+of
+one
+or
+more
+lower
+case
+alphabetic
+characters
+(
+<code>
+@[a-z]+
+</code>
+).
+JSON-LD
+documents
+<em class="rfc2119" title="should not">
+should
+not
+</em>
+define
+terms
+beginning
+with
+'
+<code>
+@
+</code>
+'.
+(See
+<a href="#syntax-tokens-and-keywords" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.2
+</del>
+<ins class="diff-chg">3.4
+</ins>
+</span>
+<span class="sec-title">
+Syntax
+Tokens
+and
+Keywords
+</span>
+</a>
+for
+a
+complete
+definition
+of
+JSON-LD
+keywords).
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+The
+JSON-LD
+context
+allows
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>
+to
+be
+aliased
+within
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+Whenever
+a
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+is
+discussed,
+this
+is
+also
+understood
+to
+apply
+to
+an
+alias
+for
+that
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+For
+example,
+if
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+defines
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+<code>
+id
+</code>
+as
+an
+alias
+for
+<code>
+@id
+</code>,
+that
+alias
+may
+be
+legitimately
+used
+as
+a
+substitution
+for
+<code>
+@id
+</code>.
+Note
+that
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+aliases
+are
+not
+expanded
+during
+context
+processing.
+</p>
+</div>
+<p>
+A
+JSON-LD
+document
+is
+either
+a
+a
+single
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+or
+a
+JSON
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+containing
+a
+set
+of
+one
+or
+more
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 60</span>: Simple node definition</div><pre class="example">{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<div class="example"><div class="example-title"><span>Example 61</span>: Array of node definitions</div><pre class="example">[
+ {
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+ }, {
+ "name": "Gregg Kellogg",
+ "homepage": "http://greggkellogg.net/",
+ "depiction": "http://twitter.com/account/profile_image/gkellogg"
+ }
+]
+</pre>
+</div>
+<section id="grammar-node-definition">
+<h3>
+<span class="secno">
+A.1
+</span>
+Node
+Definition
+</h3>
+<p>
+A
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+is
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+one
+or
+more
+<del class="diff-old">key/value
+</del>
+<ins class="diff-chg">key-value
+</ins>
+pairs.
+Keys
+are
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s,
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+defined
+within
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>,
+or
+one
+of
+the
+following
+keywords:
+</p>
+<ul>
+<li>
+<code>
+@context
+</code>,
+</li>
+<li>
+<code>
+@graph
+</code>,
+</li>
+<li>
+<code>
+@id
+</code>,
+or
+</li>
+<li>
+<code>
+@type
+</code>
+</li>
+</ul>
+<p>
+If
+the
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+contains
+the
+<code>
+@context
+</code>
+key,
+<del class="diff-old">it's
+</del>
+<ins class="diff-chg">its
+</ins>
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+one
+of
+the
+following:
+</p>
+<ul>
+<li>
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+with
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+</li>
+<li>
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+conforming
+the
+the
+syntax
+requirements
+stated
+in
+<a href="#grammar-context" class="sec-ref">
+<span class="secno">
+A.6
+</span>
+<span class="sec-title">
+Context
+Definition
+</span>
+</a>,
+or
+</li>
+<li>
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+composed
+of
+any
+number
+of
+the
+previous
+two
+expressions.
+</li>
+</ul>
+<div class="example"><div class="example-title"><span>Example 62</span>: Node definition with external context</div><pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person.jsonld"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+See
+<a href="#node-identifiers" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.6
+</del>
+<ins class="diff-chg">3.8
+</ins>
+</span>
+<span class="sec-title">
+Node
+Identifiers
+</span>
+</a>,
+<a href="#compact-iris" class="sec-ref">
+<span class="secno">
+4.1
+</span>
+<span class="sec-title">
+Compact
+IRIs
+</span>
+</a>,
+and
+<a href="#identifying-unlabeled-nodes" class="sec-ref">
+<span class="secno">
+4.12
+</span>
+<span class="sec-title">
+Identifying
+Unlabeled
+Nodes
+</span>
+</a>
+for
+further
+discussion
+on
+<code>
+@id
+</code>
+values.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+contains
+the
+<code>
+@id
+</code>
+key,
+it's
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+having
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+(including
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>
+),
+or
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+expanding
+into
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+an
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+node
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 63</span>: Node definition with @id</div><pre class="example">{
+ "@context": "http://json-ld.org/contexts/person.jsonld",
+ <span class="diff">"@id": "http://manu.sporny.org/i/public"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+If
+the
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+contains
+the
+<code>
+@type
+</code>
+key,
+it's
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+having
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+expanding
+into
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+of
+any
+of
+these.
+</p>
+<del class="diff-old">Note
+</del>
+<p>
+A
+JSON-LD
+processor
+<em class="rfc2119" title="should">
+should
+</em>
+process
+non-conforming
+documents
+having
+<code>
+@type
+</code>
+values
+including
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+or
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>
+entries
+but
+<em class="rfc2119" title="must">
+must
+</em>
+discard
+everything
+except
+for
+the
+value
+of
+the
+<code>
+@id
+</code>
+key.
+</p>
+<div class="example"><div class="example-title"><span>Example 64</span>: Node definition with @type</div><pre class="example">{
+ "@context": "http://json-ld.org/contexts/person.jsonld",
+ "@id": "http://manu.sporny.org/i/public",
+ <span class="diff">"@type": "Person"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+</div>
+<p>
+See
+<a href="#specifying-the-type" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.7
+</del>
+<ins class="diff-chg">3.9
+</ins>
+</span>
+<span class="sec-title">
+Specifying
+the
+Type
+</span>
+</a>
+for
+further
+discussion
+on
+<code>
+@type
+</code>
+values.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+contains
+the
+<code>
+@graph
+</code>
+key,
+it's
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+or
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+of
+zero
+or
+more
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>.
+If
+the
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+contains
+an
+<code>
+@id
+</code>
+keyword,
+its
+value
+is
+used
+as
+the
+label
+of
+a
+named
+graph.
+</p>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+As
+a
+special
+case,
+if
+the
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+contains
+no
+keys
+other
+than
+<code>
+@graph
+</code>
+and
+<code>
+@context
+</code>,
+and
+the
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+the
+root
+of
+the
+JSON-LD
+document,
+the
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+not
+treated
+as
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+;
+this
+is
+used
+as
+a
+way
+of
+defining
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>
+that
+may
+not
+form
+a
+connected
+graph.
+This
+allows
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+to
+be
+defined
+which
+is
+shared
+by
+all
+of
+the
+constituent
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definitions
+</a>.
+</p>
+</div>
+<div class="example"><div class="example-title"><span>Example 65</span>: Multiple node definitions with a single context using @graph</div><pre class="example">{
+ "@context": ...,
+ "<span class="diff">@graph</span>":
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}
+</pre>
+</div>
+<p>
+See
+<a href="#named-graphs" class="sec-ref">
+<span class="secno">
+4.11
+</span>
+<span class="sec-title">
+Named
+Graphs
+</span>
+</a>
+for
+further
+discussion
+on
+<code>
+@graph
+</code>
+values.
+</p>
+<p>
+A
+JSON-LD
+document
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+contain
+any
+<del class="diff-old">other
+</del>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+or
+alias
+<del class="diff-old">expanding
+</del>
+<ins class="diff-chg">that
+expands
+</ins>
+to
+<del class="diff-old">any
+other
+</del>
+<ins class="diff-chg">another
+</ins>
+keyword.
+</p>
+<p>
+Other
+keys
+<em class="rfc2119" title="must">
+must
+</em>
+expand
+to
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+using
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+The
+values
+associated
+with
+these
+keys
+may
+be
+any
+of
+the
+following:
+</p>
+<ul>
+<li>
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="true" href="#dfn-true">
+true
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="false" href="#dfn-false">
+false
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">
+language-tagged
+string
+</a>,
+</li>
+<li>
+<code>
+@set
+</code>
+or
+<code>
+@list
+</code>
+definition
+(see
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+),
+</li>
+<li>
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+zero
+or
+more
+of
+these,
+or
+</li>
+<li>
+<ins class="diff-chg">a
+</ins>
+<a class="tref internalDFN" title="language_map" href="#dfn-language_map">
+language
+map
+<del class="diff-old">.
+</del>
+</a>
+</li>
+</ul>
+</section>
+<section id="grammar-node-reference">
+<h3>
+<span class="secno">
+A.2
+</span>
+Node
+Reference
+</h3>
+<p>
+A
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+only
+the
+<code>
+@id
+</code>
+(or
+<del class="diff-old">alias)
+</del>
+<ins class="diff-chg">an
+alias
+for
+</ins><code><ins class="diff-chg">
+@id
+</ins></code><ins class="diff-chg">
+)
+</ins>
+is
+a
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>
+and
+not
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 66</span>: Explicit node reference</div><pre class="example">{
+ "@context": ...,
+ "@graph": [
+ {
+ "@id": "http://example.org/library",
+ "@type": "ex:Library",
+ <span class="diff">"ex:contains": {"@id": "http://example.org/library/the-republic"}</span>
+ }, {
+ "@id": "http://example.org/library/the-republic",
+ "@type": "ex:Book",
+ "dc:creator": "Plato",
+ "dc:title": "The Republic",
+ <span class="diff">"ex:contains": {"@id": "http://example.org/library/the-republic#introduction"}</span>
+ }, {
+ "@id": "http://example.org/library/the-republic#introduction",
+ "@type": "ex:Chapter",
+ "dc:description": "An introductory chapter on The Republic.",
+ "dc:title": "The Introduction"
+ }
+ ]
+}
+}
+</pre>
+</div>
+</section>
+<section id="grammar-language-map">
+<h3>
+<span class="secno">
+A.3
+</span>
+Language
+Map
+</h3>
+<p>
+A
+<a class="tref internalDFN" title="language_map" href="#dfn-language_map">
+language
+map
+</a>
+may
+be
+used
+as
+a
+term
+value
+within
+a
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>
+if
+the
+term
+is
+defined
+with
+<code>
+@container
+</code>
+set
+to
+<code>
+@language
+</code>.
+</p>
+<p>
+The
+keys
+of
+a
+<a class="tref internalDFN" title="language_map" href="#dfn-language_map">
+language
+map
+</a>
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+string
+with
+an
+associated
+value
+that
+is
+any
+of
+the
+following
+types:
+</p>
+<ul>
+<li>
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="true" href="#dfn-true">
+true
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="false" href="#dfn-false">
+false
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">
+language-tagged
+string
+</a>,
+</li>
+<li>
+<code>
+@set
+</code>
+or
+<code>
+@list
+</code>
+definition
+(see
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+),
+or
+</li>
+<li>
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+zero
+or
+more
+of
+these
+</li>
+</ul>
+<p class="issue resolved" data-number="133">
+We
+had
+also
+discussed
+values
+other
+than
+strings,
+such
+as
+those
+that
+might
+represent
+a
+more
+reified
+version
+of
+a
+value
+with
+other
+properties,
+such
+as
+is
+described
+using
+<a href="http://www.w3.org/TR/skos-reference/skos-xl.html">
+SKOS-XL
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 67</span>: Language map expressing a property in three languages</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ <span class="diff">"@container": "@language"</span>
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "en": "JSON-LD Syntax",
+ "ru": "JSON-LD Синтаксис",
+ "ja": "JSON-LDの構文"
+ }</span>
+...
+}
+</pre>
+</div>
+</section>
+<section id="grammar-expanded-values">
+<h3>
+<span class="secno">
+A.4
+</span>
+Expanded
+Values
+</h3>
+<p>
+An
+<dfn title="expanded_value" id="dfn-expanded_value">
+expanded
+value
+</dfn>
+is
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+the
+<code>
+@value
+</code>
+key,
+or
+an
+alias
+for
+the
+<code>
+@value
+</code>
+value
+key.
+It
+<em class="rfc2119" title="may">
+may
+</em>
+also
+contain
+the
+<code>
+@type
+</code>
+or
+<code>
+@language
+</code>
+keys,
+or
+their
+respective
+keyword
+aliases.
+An
+<a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">
+expanded
+value
+</a>
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+contain
+keys
+other
+than
+<code>
+@value
+</code>,
+<code>
+@language
+</code>,
+and
+<code>
+@type
+</code>.
+An
+<a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">
+expanded
+value
+</a>
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+contain
+both
+the
+<code>
+@language
+</code>
+and
+<code>
+@type
+</code>
+keys.
+</p>
+<p>
+The
+value
+of
+the
+<code>
+@value
+</code>
+key,
+or
+its
+alias,
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>,
+<a class="tref internalDFN" title="true" href="#dfn-true">
+true
+</a>,
+or
+<a class="tref internalDFN" title="false" href="#dfn-false">
+false
+</a>.
+</p>
+<p>
+If
+an
+<a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">
+expanded
+value
+</a>
+contains
+a
+<code>
+@language
+</code>
+key,
+it
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+contain
+any
+other
+key
+except
+<code>
+@value
+</code>.
+The
+value
+of
+the
+<code>
+@language
+</code>
+key
+<em class="rfc2119" title="must">
+must
+</em>
+have
+the
+lexical
+form
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+],
+or
+be
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>.
+</p>
+<p>
+If
+an
+<a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">
+expanded
+value
+</a>
+contains
+a
+<code>
+@type
+</code>
+key,
+it
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+contain
+any
+other
+key
+except
+<code>
+@value
+</code>.
+The
+value
+of
+<code>
+@type
+</code>
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+<code>
+null
+</code>.
+</p>
+<p>
+See
+<a href="#typed-values" class="sec-ref">
+<span class="secno">
+4.2
+</span>
+<span class="sec-title">
+Typed
+Values
+</span>
+</a>
+and
+<a href="#language-tagged-strings" class="sec-ref">
+<span class="secno">
+4.3
+</span>
+<span class="sec-title">
+Language-tagged
+Strings
+</span>
+</a>
+for
+a
+further
+discussion
+of
+<a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">
+expanded
+values
+</a>.
+</p>
+</section>
+<section id="grammar-set-list">
+<h3>
+<span class="secno">
+A.5
+</span>
+List
+and
+Set
+Values
+</h3>
+<p>
+A
+<dfn title="list" id="dfn-list">
+list
+</dfn>
+is
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+having
+only
+the
+<code>
+@list
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+Its
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+of
+any
+of
+the
+following:
+</p>
+<ul>
+<li>
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>,
+or
+</li>
+<li>
+<a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">
+language-tagged
+string
+</a>.
+</li>
+</ul>
+<p>
+A
+<dfn title="set" id="dfn-set">
+set
+</dfn>
+is
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+having
+only
+the
+<code>
+@set
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>.
+Its
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+of
+any
+of
+the
+following:
+</p>
+<ul>
+<li>
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">
+node
+reference
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">
+node
+definition
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>,
+</li>
+<li>
+<a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">
+language-tagged
+string
+</a>,
+</li>
+<li>
+<code>
+@set
+</code>
+or
+<code>
+@list
+</code>
+definition
+(see
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+),
+or
+</li>
+<li>
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+zero
+or
+more
+of
+these.
+</li>
+</ul>
+<p>
+See
+<a href="#sets-and-lists" class="sec-ref">
+<span class="secno">
+4.9
+</span>
+<span class="sec-title">
+Sets
+and
+Lists
+</span>
+</a>
+for
+a
+further
+discussion
+of
+List
+and
+Set
+Values.
+</p>
+</section>
+<section id="grammar-context">
+<h3>
+<span class="secno">
+A.6
+</span>
+Context
+Definition
+</h3>
+<p>
+A
+<dfn title="context_definition" id="dfn-context_definition">
+context
+definition
+</dfn>
+is
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+one
+or
+more
+<del class="diff-old">key/value
+</del>
+<ins class="diff-chg">key-value
+</ins>
+pairs.
+Keys
+are
+non-keyword
+<a class="tref internalDFN" title="string" href="#dfn-string">
+strings
+</a>
+or
+the
+<code>
+@language
+</code>
+or
+<code>
+@vocab
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keywords
+</a>.
+A
+<a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">
+context
+definition
+</a>
+<em class="rfc2119" title="should not">
+should
+not
+</em>
+contain
+any
+keys
+having
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>
+other
+than
+<code>
+@language
+</code>
+or
+<code>
+@vocab
+</code>.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">
+context
+definition
+</a>
+has
+a
+<code>
+@language
+</code>
+key,
+the
+value
+<em class="rfc2119" title="must">
+must
+</em>
+have
+the
+lexical
+form
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+or
+be
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">
+context
+definition
+</a>
+has
+a
+<code>
+@vocab
+</code>
+key,
+the
+value
+<em class="rfc2119" title="must">
+must
+</em>
+have
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+be
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>.
+</p>
+<p>
+Other
+keys
+are
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+definitions.
+Their
+values
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>,
+or
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+having
+the
+form
+of
+an
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+(see
+<a href="#expanded-term-definition" class="sec-ref">
+<span class="secno">
+4.5
+</span>
+<span class="sec-title">
+Expanded
+Term
+Definition
+</span>
+</a>
+).
+</p>
+<p>
+An
+<dfn title="expanded_term_definition" id="dfn-expanded_term_definition">
+expanded
+term
+definition
+</dfn>
+is
+composed
+of
+zero
+or
+more
+keys
+from
+<code>
+@id
+</code>,
+<code>
+@type
+</code>,
+<code>
+@language
+</code>
+or
+<code>
+@container
+</code>.
+An
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+<del class="diff-old">must
+</del>
+<em class="rfc2119" title="should not">
+<ins class="diff-chg">should
+</ins>
+not
+</em>
+contain
+any
+other
+keys.
+All
+values
+associated
+with
+<code>
+@id
+</code>
+<em class="rfc2119" title="must">
+must
+</em>
+expand
+to
+an
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+definition
+is
+not
+a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+the
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+<em class="rfc2119" title="must">
+must
+</em>
+include
+the
+<code>
+@id
+</code>
+key.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+contains
+the
+<code>
+@id
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>,
+it
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+having
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+in
+the
+defining
+<a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">
+context
+definition
+</a>
+or
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>,
+or
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+composed
+of
+any
+of
+the
+previous
+allowed
+values.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+contains
+the
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>,
+it
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+having
+the
+lexical
+form
+of
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>,
+or
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+defined
+in
+the
+defining
+<a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">
+context
+definition
+</a>
+or
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+contains
+the
+<code>
+@language
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>,
+the
+value
+<em class="rfc2119" title="must">
+must
+</em>
+have
+the
+lexical
+form
+described
+in
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+or
+be
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>.
+</p>
+<p>
+If
+the
+<a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">
+expanded
+term
+definition
+</a>
+contains
+the
+<code>
+@container
+</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">
+keyword
+</a>,
+the
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+either
+<code>
+@list
+</code>,
+<code>
+@set
+</code>,
+<code>
+@language
+</code>,
+or
+be
+<a class="tref internalDFN" title="null" href="#dfn-null">
+null
+</a>.
+If
+the
+value
+is
+<code>
+@language
+</code>,
+when
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+is
+used
+outside
+of
+the
+<code>
+@context
+</code>,
+the
+associated
+value
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+whose
+keys
+are
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+s
+that
+are
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+language
+identifiers.
+The
+values
+associated
+with
+each
+[
+<cite>
+<a class="bibref" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+language
+string
+<em class="rfc2119" title="must">
+must
+</em>
+be
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+or
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>
+of
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+s.
+</p>
+<p>
+See
+<a href="#the-context" class="sec-ref">
+<span class="secno">
+<del class="diff-old">3.3
+</del>
+<ins class="diff-chg">3.5
+</ins>
+</span>
+<span class="sec-title">
+The
+Context
+</span>
+</a>
+and
+<a href="#expanded-term-definition" class="sec-ref">
+<span class="secno">
+4.5
+</span>
+<span class="sec-title">
+Expanded
+Term
+Definition
+</span>
+</a>
+for
+a
+further
+discussion
+of
+contexts.
+</p>
+</section>
+<div class="example"><div class="example-title"><span>Example 68</span>: Context definition with simple terms, expanded term definitions and @language</div><pre class="example">{
+ "@language": "en",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "name": "foaf:name",
+ "depiction": {"@id": "foaf:depiction", "@type": "@id"},
+ "modified": {"@id": "http://purl.org/dc/terms/modified", "@type": "xsd:dateTime"},
+ "homepage": {"@id": "foaf:homepage", "@type": "@id", "@container": "@list"}
+}
+</pre>
+</div>
+</section>
+<section class="appendix informative" id="relationship-to-other-linked-data-formats-and-data-models">
+<h2>
+<span class="secno">
+B.
+</span>
+Relationship
+to
+Other
+Linked
+Data
+Formats
+and
+Data
+Models
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<div class="issue">
+<div class="issue-title">
+<span>
+Issue
+</span>
+</div>
+<p class="">
+The
+intent
+of
+the
+Working
+Group
+and
+the
+Editors
+of
+this
+specification
+is
+to
+eventually
+align
+terminology
+used
+in
+this
+document
+with
+the
+terminology
+used
+in
+the
+RDF
+Concepts
+document
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+]
+to
+the
+extent
+to
+which
+it
+makes
+sense
+to
+do
+so.
+In
+general,
+if
+there
+is
+an
+analogue
+to
+terminology
+used
+in
+this
+document
+in
+the
+RDF
+Concepts
+document,
+the
+preference
+is
+to
+use
+the
+terminology
+in
+the
+RDF
+Concepts
+document.
+</p>
+</div>
+<p>
+JSON-LD
+is
+a
+specification
+for
+representing
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+in
+JSON.
+A
+common
+way
+of
+working
+with
+Linked
+Data
+is
+through
+<dfn title="rdf" id="dfn-rdf">
+RDF
+</dfn>,
+the
+Resource
+Description
+Framework.
+RDF
+can
+be
+expressed
+using
+JSON-LD
+by
+associating
+JSON-LD
+concepts
+such
+as
+<code>
+@id
+</code>
+and
+<code>
+@type
+</code>
+with
+the
+equivalent
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+in
+RDF.
+Further
+information
+about
+RDF
+may
+be
+found
+in
+the
+[
+<cite>
+<a class="bibref" href="#bib-RDF-PRIMER">
+RDF-PRIMER
+</a>
+</cite>
+].
+</p>
+<p>
+The
+JSON-LD
+markup
+examples
+below
+demonstrate
+how
+JSON-LD
+can
+be
+used
+to
+express
+semantic
+data
+marked
+up
+in
+other
+languages
+and
+data
+models
+such
+as
+RDF,
+Turtle,
+RDFa,
+Microformats,
+and
+Microdata.
+These
+sections
+are
+merely
+provided
+as
+evidence
+that
+JSON-LD
+is
+very
+flexible
+in
+what
+it
+can
+express
+across
+different
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+approaches.
+Further
+information
+on
+transforming
+JSON-LD
+into
+RDF
+are
+detailed
+in
+the
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+</p>
+<section id="rdf">
+<h3>
+<span class="secno">
+B.1
+</span>
+RDF
+</h3>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+The
+RDF
+data
+model,
+as
+outlined
+in
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+],
+is
+an
+abstract
+syntax
+for
+representing
+a
+directed
+graph
+of
+information.
+JSON-LD
+is
+capable
+of
+serializing
+any
+RDF
+graph,
+and
+performing
+full
+RDF
+to
+JSON-LD
+to
+RDF
+round-tripping.
+A
+complete
+description
+of
+how
+JSON-LD
+maps
+to
+RDF
+and
+algorithms
+detailing
+how
+one
+can
+convert
+from
+RDF
+to
+JSON-LD
+and
+from
+JSON-LD
+to
+RDF
+are
+included
+in
+the
+JSON-LD
+API
+[
+<cite>
+<a class="bibref" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+]
+specification.
+</p>
+<p>
+<ins class="diff-chg">JSON-LD
+allows
+properties
+to
+be
+BNodes,
+while
+RDF
+does
+not.
+Expressing
+properties
+as
+BNodes
+in
+JSON-LD
+only
+becomes
+an
+issue
+(and
+could
+raise
+an
+exception)
+when
+it
+is
+transformed
+to
+RDF.
+</ins></p><p><ins class="diff-chg">
+Note
+that
+the
+JSON-LD
+data
+model
+is
+silent
+on
+the
+topic
+of
+</ins><a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node"><ins class="diff-chg">
+unlabeled
+nodes
+</ins></a>.<ins class="diff-chg">
+Nevertheless,
+this
+specification
+allows
+for
+the
+expression
+of
+</ins><a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node"><ins class="diff-chg">
+unlabeled
+nodes
+</ins></a>,<ins class="diff-chg">
+as
+most
+graph-based
+data
+sets
+on
+the
+Web
+contain
+a
+number
+of
+associated
+nodes
+that
+are
+not
+named
+and
+thus
+are
+not
+directly
+de-referenceable.
+</ins></p>
+<section id="turtle">
+<h4>
+<span class="secno">
+<del class="diff-old">B.2
+</del>
+<ins class="diff-chg">B.1.1
+</ins>
+</span>
+Turtle
+</h4>
+<p>
+<em>
+<ins class="diff-chg">This
+section
+is
+non-normative.
+</ins></em></p>
+<p>
+The
+following
+are
+examples
+of
+converting
+<a class="tref internalDFN" title="rdf" href="#dfn-rdf">
+RDF
+</a>
+expressed
+in
+[
+<cite>
+<a class="bibref" href="#bib-TURTLE-TR">
+TURTLE-TR
+</a>
+</cite>
+]
+into
+JSON-LD.
+</p>
+<section id="prefix-definitions">
+<h5>
+<span class="secno">
+<del class="diff-old">B.2.1
+</del>
+<ins class="diff-chg">B.1.1.1
+</ins>
+</span>
+Prefix
+definitions
+</h5>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+The
+JSON-LD
+context
+has
+direct
+equivalents
+for
+the
+Turtle
+<code>
+@prefix
+</code>
+declaration:
+</p>
+<div class="example"><div class="example-title"><span>Example 69</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+<http://manu.sporny.org/i/public> a foaf:Person;
+ foaf:name "Manu Sporny";
+foaf:homepage
+<http://manu.sporny.org/>
+.
+</pre>
+</div>
+<div class="example"><div class="example-title"><span>Example 70</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": { "@id": "http://manu.sporny.org/" }
+}
+</pre>
+</div>
+<div class="note">
+<div class="note-title">
+<span>
+Note
+</span>
+</div>
+<p class="">
+JSON-LD
+has
+no
+equivalent
+for
+the
+Turtle
+<code>
+@base
+</code>
+declaration.
+</p>
+</div>
+</section>
+<section id="embedding-1">
+<h5>
+<span class="secno">
+<del class="diff-old">B.2.2
+</del>
+<ins class="diff-chg">B.1.1.2
+</ins>
+</span>
+Embedding
+</h5>
+<p>
+Both
+Turtle
+and
+JSON-LD
+allow
+embedding,
+although
+Turtle
+only
+allows
+embedding
+of
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">
+unlabeled
+nodes
+</a>.
+</p>
+</section>
+<div class="example"><div class="example-title"><span>Example 71</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+<http://manu.sporny.org/i/public>
+ a foaf:Person;
+ foaf:name "Manu Sporny";
+foaf:knows
+[
+a
+foaf:Person;
+foaf:name
+"Gregg
+Kellogg"
+]
+.
+</pre>
+</div>
+<div class="example"><div class="example-title"><span>Example 72</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:knows":
+ {
+ "@type": "foaf:Person",
+ "foaf:name": "Gregg Kellogg"
+ }
+}
+</pre>
+</div>
+<section id="lists">
+<h5>
+<span class="secno">
+<del class="diff-old">B.2.3
+</del>
+<ins class="diff-chg">B.1.1.3
+</ins>
+</span>
+Lists
+</h5>
+<p>
+Both
+JSON-LD
+and
+Turtle
+can
+represent
+sequential
+lists
+of
+values.
+</p>
+<div class="example"><div class="example-title"><span>Example 73</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+<http://example.org/people#joebob> a foaf:Person;
+ foaf:name "Joe Bob";
+foaf:nick
+(
+"joe"
+"bob"
+"jaybee"
+)
+.
+</pre>
+</div>
+<div class="example"><div class="example-title"><span>Example 74</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://example.org/people#joebob",
+ "@type": "foaf:Person",
+ "foaf:name": "Joe Bob",
+ "foaf:nick":
+ {
+ "@list": [ "joe", "bob", "jaybee" ]
+ }
+}
+</pre>
+</div>
+</section>
+</section>
+<section id="rdfa">
+<h4>
+<span class="secno">
+<del class="diff-old">B.3
+</del>
+<ins class="diff-chg">B.1.2
+</ins>
+</span>
+RDFa
+</h4>
+<p>
+The
+following
+example
+describes
+three
+people
+with
+their
+respective
+names
+and
+homepages.
+</p>
+<div class="example"><div class="example-title"><span>Example 75</span></div><pre class="example"><div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>>
+ <ul>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name" </span>>Bob</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name" </span>>Eve</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name" </span>>Manu</a>
+ </li>
+ </ul>
+</div>
+</pre>
+</div>
+<p>
+An
+example
+JSON-LD
+implementation
+using
+a
+single
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+is
+described
+below.
+</p>
+<div class="example"><div class="example-title"><span>Example 76</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@graph":
+ [
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/bob/",
+ "foaf:name": "Bob"
+ },
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/eve/",
+ "foaf:name": "Eve"
+ },
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/manu/",
+ "foaf:name": "Manu"
+ }
+ ]
+}
+</pre>
+</div>
+</section>
+<section id="microformats">
+<h4>
+<span class="secno">
+<del class="diff-old">B.4
+</del>
+<ins class="diff-chg">B.1.3
+</ins>
+</span>
+Microformats
+</h4>
+<p>
+The
+following
+example
+uses
+a
+simple
+Microformats
+hCard
+example
+to
+express
+how
+the
+Microformat
+is
+represented
+in
+JSON-LD.
+</p>
+<div class="example"><div class="example-title"><span>Example 77</span></div><pre class="example"><div class="vcard">
+ <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</div>
+</pre>
+</div>
+<p>
+The
+representation
+of
+the
+hCard
+expresses
+the
+Microformat
+terms
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+and
+uses
+them
+directly
+for
+the
+<code>
+url
+</code>
+and
+<code>
+fn
+</code>
+properties.
+Also
+note
+that
+the
+Microformat
+to
+JSON-LD
+processor
+has
+generated
+the
+proper
+URL
+type
+for
+<code>
+http://tantek.com/
+</code>.
+</p>
+<div class="example"><div class="example-title"><span>Example 78</span></div><pre class="example">{
+ "@context":
+ {
+ "vcard": "http://microformats.org/profile/hcard#vcard",
+ "url":
+ {
+ "@id": "http://microformats.org/profile/hcard#url",
+ "@type": "@id"
+ },
+ "fn": "http://microformats.org/profile/hcard#fn"
+ },
+ "@type": "vcard",
+ "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+}
+</pre>
+</div>
+</section>
+<section id="microdata">
+<h4>
+<span class="secno">
+<del class="diff-old">B.5
+</del>
+<ins class="diff-chg">B.1.4
+</ins>
+</span>
+Microdata
+</h4>
+<p>
+The
+microdata
+example
+below
+expresses
+book
+information
+as
+a
+microdata
+Work
+item.
+</p>
+<div class="example"><div class="example-title"><span>Example 79</span></div><pre class="example"><dl itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Work"
+ itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N">
+ <dt>Title</dt>
+ <dd><cite itemprop="http://purl.org/dc/terms/title">Just a Geek</cite></dd>
+ <dt>By</dt>
+ <dd><span itemprop="http://purl.org/dc/terms/creator">Wil Wheaton</span></dd>
+ <dt>Format</dt>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596007683.BOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK">
+ Print
+ </dd>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596802189.EBOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK">
+ Ebook
+ </dd>
+</dl>
+</pre>
+</div>
+<p>
+Note
+that
+the
+JSON-LD
+representation
+of
+the
+Microdata
+information
+stays
+true
+to
+the
+desires
+of
+the
+Microdata
+community
+to
+avoid
+contexts
+and
+instead
+refer
+to
+items
+by
+their
+full
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 80</span></div><pre class="example">[
+ {
+ "@id": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
+ "@type": "http://purl.org/vocab/frbr/core#Work",
+ "http://purl.org/dc/terms/title": "Just a Geek",
+ "http://purl.org/dc/terms/creator": "Whil Wheaton",
+ "http://purl.org/vocab/frbr/core#realization":
+ [
+ "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "http://purl.oreilly.com/products/9780596802189.EBOOK"
+ ]
+ },
+ {
+ "@id": "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "@type": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
+ },
+ {
+ "@id": "http://purl.oreilly.com/products/9780596802189.EBOOK",
+ "@type": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
+ }
+]
+</pre>
+</div>
+</section>
+</section>
+<section class="appendix informative" id="iana-considerations">
+<h3>
+<span class="secno">
+<del class="diff-old">C.
+</del>
+<ins class="diff-chg">B.2
+</ins>
+</span>
+IANA
+Considerations
+</h3>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+This
+section
+is
+included
+merely
+for
+standards
+community
+review
+and
+will
+be
+submitted
+to
+the
+Internet
+Engineering
+Steering
+Group
+if
+this
+specification
+becomes
+a
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+Recommendation.
+</p>
+<h3 id="application-ld-json">
+application/ld+json
+</h3>
+<dl>
+<dt>
+Type
+name:
+</dt>
+<dd>
+application
+</dd>
+<dt>
+Subtype
+name:
+</dt>
+<dd>
+ld+json
+</dd>
+<dt>
+Required
+parameters:
+</dt>
+<dd>
+None
+</dd>
+<dt>
+Optional
+parameters:
+</dt>
+<dd>
+<dl>
+<dt>
+<code>
+form
+</code>
+</dt>
+<dd>
+Determines
+the
+serialization
+form
+for
+the
+JSON-LD
+document.
+The
+only
+valid
+value
+at
+the
+moment
+is
+<code>
+expanded
+</code>.
+If
+no
+form
+is
+specified
+in
+an
+HTTP
+request
+header
+to
+an
+HTTP
+server,
+the
+server
+<em class="rfc2119" title="may">
+may
+</em>
+choose
+any
+form.
+If
+no
+form
+is
+specified
+in
+an
+HTTP
+response,
+the
+form
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+be
+assumed
+to
+take
+any
+particular
+form.
+</dd>
+</dl>
+</dd>
+<dt>
+Encoding
+considerations:
+</dt>
+<dd>
+The
+same
+as
+the
+<code>
+application/json
+</code>
+MIME
+media
+type.
+</dd>
+<dt>
+Security
+considerations:
+</dt>
+<dd>
+Since
+JSON-LD
+is
+intended
+to
+be
+a
+pure
+data
+exchange
+format
+for
+directed
+graphs,
+the
+serialization
+<em class="rfc2119" title="should not">
+should
+not
+</em>
+be
+passed
+through
+a
+code
+execution
+mechanism
+such
+as
+JavaScript's
+<code>
+eval()
+</code>
+function.
+It
+is
+<em class="rfc2119" title="recommended">
+recommended
+</em>
+that
+a
+conforming
+parser
+does
+not
+attempt
+to
+directly
+evaluate
+the
+JSON-LD
+serialization
+and
+instead
+purely
+parse
+the
+input
+into
+a
+language-native
+data
+structure.
+</dd>
+<dt>
+Interoperability
+considerations:
+</dt>
+<dd>
+Not
+Applicable
+</dd>
+<dt>
+Published
+specification:
+</dt>
+<dd>
+The
+<a href="http://json-ld.org/spec/latest/">
+JSON-LD
+</a>
+specification.
+</dd>
+<dt>
+Applications
+that
+use
+this
+media
+type:
+</dt>
+<dd>
+Any
+programming
+environment
+that
+requires
+the
+exchange
+of
+directed
+graphs.
+Implementations
+of
+JSON-LD
+have
+been
+created
+for
+JavaScript,
+Python,
+Ruby,
+PHP
+and
+C++.
+</dd>
+<dt>
+Additional
+information:
+</dt>
+<dd>
+<dl>
+<dt>
+Magic
+number(s):
+</dt>
+<dd>
+Not
+Applicable
+</dd>
+<dt>
+File
+extension(s):
+</dt>
+<dd>.jsonld
+</dd>
+<dt>
+Macintosh
+file
+type
+code(s):
+</dt>
+<dd>
+TEXT
+</dd>
+</dl>
+</dd>
+<dt>
+Person
+&
+email
+address
+to
+contact
+for
+further
+information:
+</dt>
+<dd>
+Manu
+Sporny
+<msporny@digitalbazaar.com>
+</dd>
+<dt>
+Intended
+usage:
+</dt>
+<dd>
+Common
+</dd>
+<dt>
+Restrictions
+on
+usage:
+</dt>
+<dd>
+None
+</dd>
+<dt>
+Author(s):
+</dt>
+<dd>
+Manu
+Sporny,
+Gregg
+Kellogg,
+Markus
+Lanthaler,
+Dave
+Longley
+</dd>
+<dt>
+Change
+controller:
+</dt>
+<dd>
+<abbr title="World Wide Web Consortium">
+W3C
+</abbr>
+</dd>
+</dl>
+<p>
+Fragment
+identifiers
+used
+with
+<a href="#application-ld-json">
+application/ld+json
+</a>
+resources
+<em class="rfc2119" title="may">
+may
+</em>
+identify
+a
+node
+in
+the
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>
+expressed
+in
+the
+resource.
+This
+idiom,
+which
+is
+also
+used
+in
+RDF
+[
+<cite>
+<a class="bibref" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+],
+gives
+a
+simple
+way
+to
+"mint"
+new,
+document-local
+IRIs
+to
+label
+nodes
+and
+therefore
+contributes
+considerably
+to
+the
+expressive
+power
+of
+JSON-LD.
+</p>
+</section>
+<section class="appendix informative" id="acknowledgements">
+<h3>
+<span class="secno">
+<del class="diff-old">D.
+</del>
+<ins class="diff-chg">B.3
+</ins>
+</span>
+Acknowledgements
+</h3>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+A
+large
+amount
+of
+thanks
+goes
+out
+to
+the
+JSON-LD
+Community
+Group
+participants
+who
+worked
+through
+many
+of
+the
+technical
+issues
+on
+the
+mailing
+list
+and
+the
+weekly
+telecons
+-
+of
+special
+mention
+are
+Niklas
+Lindström,
+François
+Daoust,
+and
+Zdenko
+'Denny'
+Vrandečić.
+The
+editors
+would
+like
+to
+thank
+Mark
+Birbeck,
+who
+provided
+a
+great
+deal
+of
+the
+initial
+push
+behind
+the
+JSON-LD
+work
+via
+his
+work
+on
+RDFj.
+The
+work
+of
+Dave
+Lehn
+and
+Mike
+Johnson
+are
+appreciated
+for
+reviewing,
+and
+performing
+several
+implementations
+of
+the
+specification.
+Ian
+Davis
+is
+thanked
+for
+this
+work
+on
+RDF/JSON.
+Thanks
+also
+to
+Nathan
+Rixham,
+Bradley
+P.
+Allen,
+Kingsley
+Idehen,
+Glenn
+McDonald,
+Alexandre
+Passant,
+Danny
+Ayers,
+Ted
+Thibodeau
+Jr.,
+Olivier
+Grisel,
+Josh
+Mandel,
+Eric
+Prud'hommeaux,
+David
+Wood,
+Guus
+Schreiber,
+Pat
+Hayes,
+Sandro
+Hawke,
+and
+Richard
+Cyganiak
+for
+their
+input
+on
+the
+specification.
+</p>
+</section>
+</section>
+<section id="references" class="appendix">
+<h2>
+<span class="secno">
+<del class="diff-old">E.
+</del>
+<ins class="diff-chg">C.
+</ins>
+</span>
+References
+</h2>
+<section id="normative-references">
+<h3>
+<span class="secno">
+<del class="diff-old">E.1
+</del>
+<ins class="diff-chg">C.1
+</ins>
+</span>
+Normative
+references
+</h3>
+<dl class="bibliography">
+<dt id="bib-BCP47">
+[BCP47]
+</dt>
+<dd>
+A.
+Phillips;
+M.
+Davis.
+<a href="http://tools.ietf.org/html/bcp47">
+<cite>
+Tags
+for
+Identifying
+Languages
+</cite>
+</a>
+September
+2009.
+IETF
+Best
+Current
+Practice.
+URL:
+<a href="http://tools.ietf.org/html/bcp47">
+http://tools.ietf.org/html/bcp47
+</a>
+</dd>
+<dt id="bib-RDF-CONCEPTS">
+[RDF-CONCEPTS]
+</dt>
+<dd>
+<cite>
+<a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">
+RDF
+1.1
+Concepts
+and
+Abstract
+Syntax
+</a>
+</cite>
+Richard
+Cyganiak,
+David
+Wood,
+Editors.
+World
+Wide
+Web
+Consortium
+(work
+in
+progress).
+30
+May
+2012.
+Editor's
+Draft.
+This
+edition
+of
+the
+JSON-LD
+Syntax
+specification
+is
+http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/.
+The
+<a href="http://www.w3.org/TR/rdf11-concepts/">
+latest
+edition
+of
+the
+JSON-LD
+Syntax
+</a>
+is
+available
+at
+http://www.w3.org/TR/rdf11-concepts/
+</dd>
+<dt id="bib-RFC3987">
+[RFC3987]
+</dt>
+<dd>
+M.
+Dürst;
+M.
+Suignard.
+<a href="http://www.ietf.org/rfc/rfc3987.txt">
+<cite>
+Internationalized
+Resource
+Identifiers
+(IRIs).
+</cite>
+</a>
+January
+2005.
+Internet
+RFC
+3987.
+URL:
+<a href="http://www.ietf.org/rfc/rfc3987.txt">
+http://www.ietf.org/rfc/rfc3987.txt
+</a>
+</dd>
+<dt id="bib-RFC4627">
+[RFC4627]
+</dt>
+<dd>
+D.
+Crockford.
+<a href="http://www.ietf.org/rfc/rfc4627.txt">
+<cite>
+The
+application/json
+Media
+Type
+for
+JavaScript
+Object
+Notation
+(JSON)
+</cite>
+</a>
+July
+2006.
+Internet
+RFC
+4627.
+URL:
+<a href="http://www.ietf.org/rfc/rfc4627.txt">
+http://www.ietf.org/rfc/rfc4627.txt
+</a>
+</dd>
+<dt id="bib-RFC5988">
+[RFC5988]
+</dt>
+<dd>
+<cite>
+<a href="http://tools.ietf.org/rfc/rfc5988">
+Web
+Linking
+</a>
+</cite>
+M.
+Nottingham.
+Editor.
+October
+2010.
+IETF
+Standard.
+URL:
+<a href="http://tools.ietf.org/rfc/rfc5988.txt">
+http://tools.ietf.org/rfc/rfc5988.txt
+</a>
+</dd>
+</dl>
+</section>
+<section id="informative-references">
+<h3>
+<span class="secno">
+<del class="diff-old">E.2
+</del>
+<ins class="diff-chg">C.2
+</ins>
+</span>
+Informative
+references
+</h3>
+<dl class="bibliography">
+<dt id="bib-JSON-LD-API">
+[JSON-LD-API]
+</dt>
+<dd>
+<cite>
+<a href="http://json-ld.org/spec/ED/json-ld-api/20120524/">
+The
+JSON-LD
+API
+1.0
+</a>
+</cite>
+Manu
+Sporny,
+Gregg
+Kellogg,
+Dave
+Longley,
+Markus
+Lanthaler,
+Editors.
+World
+Wide
+Web
+Consortium
+(work
+in
+progress).
+24
+May
+2012.
+Editor's
+Draft.
+This
+edition
+of
+the
+JSON-LD
+Syntax
+specification
+is
+http://json-ld.org/spec/ED/json-ld-api/20120524/.
+The
+<a href="http://json-ld.org/spec/latest/json-ld-api/">
+latest
+edition
+of
+the
+JSON-LD
+Syntax
+</a>
+is
+available
+at
+http://json-ld.org/spec/latest/json-ld-api/
+</dd>
+<dt id="bib-RDF-PRIMER">
+[RDF-PRIMER]
+</dt>
+<dd>
+Frank
+Manola;
+Eric
+Miller.
+<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
+<cite>
+RDF
+Primer.
+</cite>
+</a>
+10
+February
+2004.
+W3C
+Recommendation.
+URL:
+<a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">
+http://www.w3.org/TR/2004/REC-rdf-primer-20040210/
+</a>
+</dd>
+<dt id="bib-RDF-SPARQL-QUERY">
+[RDF-SPARQL-QUERY]
+</dt>
+<dd>
+Andy
+Seaborne;
+Eric
+Prud'hommeaux.
+<a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115">
+<cite>
+SPARQL
+Query
+Language
+for
+RDF.
+</cite>
+</a>
+15
+January
+2008.
+W3C
+Recommendation.
+URL:
+<a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115">
+http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115
+</a>
+</dd>
+<dt id="bib-RDFA-CORE">
+[RDFA-CORE]
+</dt>
+<dd>
+Shane
+McCarron;
+et
+al.
+<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">
+<cite>
+RDFa
+Core
+1.1:
+Syntax
+and
+processing
+rules
+for
+embedding
+RDF
+through
+attributes.
+</cite>
+</a>
+7
+June
+2012.
+W3C
+Recommendation.
+URL:
+<a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">
+http://www.w3.org/TR/2012/REC-rdfa-core-20120607/
+</a>
+</dd>
+<dt id="bib-TURTLE-TR">
+[TURTLE-TR]
+</dt>
+<dd>
+Eric
+Prud'hommeaux,
+Gavin
+Carothers.
+<cite>
+<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
+Turtle:
+Terse
+RDF
+Triple
+Language.
+</a>
+</cite>
+09
+August
+2011.
+W3C
+Working
+Draft.
+URL:
+<a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">
+http://www.w3.org/TR/2011/WD-turtle-20110809/
+</a>
+</dd>
+</dl>
+</section>
+</section>
+</body>
+</html>
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+</style><link rel="stylesheet" href="http://www.w3.org/StyleSheets/TR/W3C-ED" /><script>window["_GOOG_TRANS_EXT_VER"] = "1";</script>
+<!--[if lt IE 9]><script src='undefined://www.w3.org/2008/site/js/html5shiv.js'></script><![endif]-->
+</head>
+
+<body><div class="head">
+ <p>
+
+ <a href="http://www.w3.org/"><img width="72" height="48" src="http://www.w3.org/Icons/w3c_home" alt="W3C" /></a>
+
+ </p>
+ <h1 class="title" id="title">JSON-LD Syntax 1.0</h1>
+
+ <h2 id="subtitle">A Context-based JSON Serialization for Linking Data</h2>
+
+ <h2 id="w3c-editor-s-draft-30-september-2012"><abbr title="World Wide Web Consortium">W3C</abbr> Editor's Draft 30 September 2012</h2>
+ <dl>
+
+ <dt>This version:</dt>
+ <dd><a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html">http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html</a></dd>
+ <dt>Latest published version:</dt>
+ <dd><a href="http://www.w3.org/TR/json-ld-syntax/">http://www.w3.org/TR/json-ld-syntax/</a></dd>
+
+
+ <dt>Latest editor's draft:</dt>
+ <dd><a href="http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html">http://dvcs.w3.org/hg/json-ld/raw-file/default/spec/latest/json-ld-syntax/index.html</a></dd>
+
+
+
+
+
+
+
+
+ <dt>Editors:</dt>
+ <dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://manu.sporny.org/">Manu Sporny</a>, <a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">Digital Bazaar</a></span>
+</dd>
+<dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">Gregg Kellogg</a>, <a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">Kellogg Associates</a></span>
+</dd>
+<dd rel="bibo:editor" inlist=""><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">Markus Lanthaler</a>, <a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">Graz University of Technology</a></span>
+</dd>
+
+
+ <dt>Authors:</dt>
+ <dd rel="dcterms:contributor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Manu Sporny" href="http://digitalbazaar.com/">Manu Sporny</a>, <a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">Digital Bazaar</a></span>
+</dd>
+<dd rel="dcterms:contributor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Dave Longley" href="http://digitalbazaar.com/">Dave Longley</a>, <a rel="foaf:workplaceHomepage" href="http://digitalbazaar.com/">Digital Bazaar</a></span>
+</dd>
+<dd rel="dcterms:contributor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Gregg Kellogg" href="http://greggkellogg.net/">Gregg Kellogg</a>, <a rel="foaf:workplaceHomepage" href="http://kellogg-assoc.com/">Kellogg Associates</a></span>
+</dd>
+<dd rel="dcterms:contributor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Markus Lanthaler" href="http://www.markus-lanthaler.com/">Markus Lanthaler</a>, <a rel="foaf:workplaceHomepage" href="http://www.tugraz.at/">Graz University of Technology</a></span>
+</dd>
+<dd rel="dcterms:contributor"><span typeof="foaf:Person"><a rel="foaf:homepage" property="foaf:name" content="Mark Birbeck" href="http://webbackplane.com/">Mark Birbeck</a>, <a rel="foaf:workplaceHomepage" href="http://webbackplane.com/">Backplane Ltd.</a></span>
+</dd>
+
+
+ </dl>
+
+
+ <p>
+
+ This document is also available in this non-normative format:
+
+ <a href="diff-20120830.html">diff to previous version</a>
+ </p>
+
+
+
+
+ <p class="copyright">
+ <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> ©
+ 2010-2012
+
+ <a href="http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup>
+ (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>,
+ <a href="http://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>,
+ <a href="http://www.keio.ac.jp/">Keio</a>), All Rights Reserved.
+ <abbr title="World Wide Web Consortium">W3C</abbr> <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>,
+ <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and
+ <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.
+ </p>
+
+
+ <hr />
+</div>
+<section id="abstract" class="introductory"><h2>Abstract</h2>
+<p>
+JSON has proven to be a highly useful object serialization and messaging format.
+In an attempt to harmonize the representation of <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>
+in JSON, this specification outlines a common JSON representation format for
+expressing directed graphs; mixing both Linked Data and non-Linked Data in
+a single document.
+</p>
+</section><section id="sotd" class="introductory"><h2>Status of This Document</h2>
+
+
+
+ <p>
+ <em>This section describes the status of this document at the time of its publication. Other
+ documents may supersede this document. A list of current <abbr title="World Wide Web Consortium">W3C</abbr> publications and the latest revision
+ of this technical report can be found in the <a href="http://www.w3.org/TR/"><abbr title="World Wide Web Consortium">W3C</abbr> technical reports
+ index</a> at http://www.w3.org/TR/.</em>
+ </p>
+
+<p>This document has been under development for over 20 months in the
+JSON for Linking Data Community Group. The document has recently been
+transferred to the RDF Working Group for review, improvement, and publication
+along the Recommendation track. The specification has undergone significant
+development, review, and changes during the course of the last 20 months.
+</p>
+<p>
+There are currently
+<a href="http://json-ld.org/#impl">five interoperable implementations</a>
+of this specification. There is
+a <a href="https://github.com/json-ld/json-ld.org/tree/master/test-suite">fairly complete test suite</a> and a
+<a href="http://json-ld.org/playground/">live JSON-LD editor</a>
+that is capable of demonstrating the features described in
+this document. While development on implementations, the test suite
+and the live editor will continue, they are believed to be mature enough
+to be integrated into a non-production system at this point in time with
+the expectation that they could be used in a production system within the
+next year.
+</p>
+
+<p>There are a number of ways that one may participate in the development of
+this specification:</p>
+
+<ul>
+ <li>If you want to make sure that your feedback is formally addressed by
+ the RDF Working Group, you should send it to public-rdf-comments:
+ <a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">public-rdf-comments@w3.org</a></li>
+
+ <li>Ad-hoc technical discussion primarily occurs on the public community mailing list:
+ <a href="http://lists.w3.org/Archives/Public/public-linked-json/">public-linked-json@w3.org</a></li>
+
+ <li><a href="http://json-ld.org/minutes/">Public JSON-LD Community Group teleconferences</a>
+ are held on Tuesdays at 1500UTC every week.</li>
+
+ <li>RDF Working Group teleconferences are held on Wednesdays at 1500UTC
+ every week. Participation is limited to RDF Working Group members.</li>
+
+ <li>Specification bugs and issues should be reported in the
+ <a href="https://github.com/json-ld/json-ld.org/issues">issue tracker</a>
+ if you do not want to send an e-mail to the public-rdf-comments mailing
+ list.</li>
+
+ <li><a href="https://github.com/json-ld/json-ld.org/tree/master/spec">Source code</a>
+ for the specification can be found on Github.</li>
+
+ <li>The <a href="http://webchat.freenode.net/?channels=json-ld">#json-ld</a>
+ IRC channel is available for real-time discussion on irc.freenode.net.</li>
+</ul>
+
+
+ <p>
+ This document was published by the <a href="http://www.w3.org/2011/rdf-wg/">RDF Working Group</a> as an Editor's Draft.
+
+ If you wish to make comments regarding this document, please send them to
+ <a href="mailto:public-rdf-comments@w3.org">public-rdf-comments@w3.org</a>
+ (<a href="mailto:public-rdf-comments-request@w3.org?subject=subscribe">subscribe</a>,
+ <a href="http://lists.w3.org/Archives/Public/public-rdf-comments/">archives</a>).
+
+
+ All feedback is welcome.
+ </p>
+
+ <p>
+ Publication as an Editor's Draft does not imply endorsement by the <abbr title="World Wide Web Consortium">W3C</abbr> Membership.
+ This is a draft document and may be updated, replaced or obsoleted by other documents at
+ any time. It is inappropriate to cite this document as other than work in progress.
+ </p>
+
+
+ <p>
+
+ This document was produced by a group operating under the
+ <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February 2004 <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+
+
+
+
+ <abbr title="World Wide Web Consortium">W3C</abbr> maintains a <a href="http://www.w3.org/2004/01/pp-impl/46168/status" rel="disclosure">public list of any patent disclosures</a>
+
+ made in connection with the deliverables of the group; that page also includes instructions for
+ disclosing a patent. An individual who has actual knowledge of a patent which the individual believes contains
+ <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential Claim(s)</a> must disclose the
+ information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
+ 6 of the <abbr title="World Wide Web Consortium">W3C</abbr> Patent Policy</a>.
+
+
+ </p>
+
+
+
+
+</section><section id="toc"><h2 class="introductory">Table of Contents</h2><ul class="toc"><li class="tocline"><a href="#introduction" class="tocxref"><span class="secno">1. </span>Introduction</a><ul class="toc"><li class="tocline"><a href="#how-to-read-this-document" class="tocxref"><span class="secno">1.1 </span>How to Read this Document</a></li></ul></li><li class="tocline"><a href="#design-goals-and-rationale" class="tocxref"><span class="secno">2. </span>Design Goals and Rationale</a></li><li class="tocline"><a href="#basic-concepts" class="tocxref"><span class="secno">3. </span>Basic Concepts</a><ul class="toc"><li class="tocline"><a href="#benefits-of-json-ld" class="tocxref"><span class="secno">3.1 </span>Benefits of JSON-LD</a></li><li class="tocline"><a href="#json-ld-data-model" class="tocxref"><span class="secno">3.2 </span>JSON-LD Data Model</a></li><li class="tocline"><a href="#general-terminology" class="tocxref"><span class="secno">3.3 </span>General Terminology</a></li><li class="tocline"><a href="#syntax-tokens-and-keywords" class="tocxref"><span class="secno">3.4 </span>Syntax Tokens and Keywords</a></li><li class="tocline"><a href="#the-context" class="tocxref"><span class="secno">3.5 </span>The Context</a></li><li class="tocline"><a href="#from-json-to-json-ld" class="tocxref"><span class="secno">3.6 </span>From JSON to JSON-LD</a></li><li class="tocline"><a href="#iris" class="tocxref"><span class="secno">3.7 </span>IRIs</a></li><li class="tocline"><a href="#node-identifiers" class="tocxref"><span class="secno">3.8 </span>Node Identifiers</a></li><li class="tocline"><a href="#specifying-the-type" class="tocxref"><span class="secno">3.9 </span>Specifying the Type</a></li><li class="tocline"><a href="#string-internationalization" class="tocxref"><span class="secno">3.10 </span>String Internationalization</a></li><li class="tocline"><a href="#json-ld-syntax" class="tocxref"><span class="secno">3.11 </span>JSON-LD Syntax</a></li></ul></li><li class="tocline"><a href="#advanced-concepts" class="tocxref"><span class="secno">4. </span>Advanced Concepts</a><ul class="toc"><li class="tocline"><a href="#compact-iris" class="tocxref"><span class="secno">4.1 </span>Compact IRIs</a></li><li class="tocline"><a href="#typed-values" class="tocxref"><span class="secno">4.2 </span>Typed Values</a></li><li class="tocline"><a href="#language-tagged-strings" class="tocxref"><span class="secno">4.3 </span>Language-tagged Strings</a></li><li class="tocline"><a href="#referencing-contexts-from-json-documents" class="tocxref"><span class="secno">4.4 </span>Referencing Contexts from JSON Documents</a></li><li class="tocline"><a href="#expanded-term-definition" class="tocxref"><span class="secno">4.5 </span>Expanded Term Definition</a></li><li class="tocline"><a href="#type-coercion" class="tocxref"><span class="secno">4.6 </span>Type Coercion</a></li><li class="tocline"><a href="#property-generators" class="tocxref"><span class="secno">4.7 </span>Property Generators</a></li><li class="tocline"><a href="#iri-expansion-within-a-context" class="tocxref"><span class="secno">4.8 </span><abbr title="Internationalized Resource Identifier">IRI</abbr> Expansion Within a Context</a></li><li class="tocline"><a href="#sets-and-lists" class="tocxref"><span class="secno">4.9 </span>Sets and Lists</a></li><li class="tocline"><a href="#embedding" class="tocxref"><span class="secno">4.10 </span>Embedding</a></li><li class="tocline"><a href="#named-graphs" class="tocxref"><span class="secno">4.11 </span>Named Graphs</a></li><li class="tocline"><a href="#identifying-unlabeled-nodes" class="tocxref"><span class="secno">4.12 </span>Identifying Unlabeled Nodes</a></li><li class="tocline"><a href="#aliasing-keywords" class="tocxref"><span class="secno">4.13 </span>Aliasing Keywords</a></li><li class="tocline"><a href="#expanded-document-form" class="tocxref"><span class="secno">4.14 </span>Expanded Document Form</a></li><li class="tocline"><a href="#compact-document-form" class="tocxref"><span class="secno">4.15 </span>Compact Document Form</a></li></ul></li><li class="tocline"><a href="#json-ld-grammar" class="tocxref"><span class="secno">A. </span>JSON-LD Grammar</a><ul class="toc"><li class="tocline"><a href="#grammar-node-definition" class="tocxref"><span class="secno">A.1 </span>Node Definition</a></li><li class="tocline"><a href="#grammar-node-reference" class="tocxref"><span class="secno">A.2 </span>Node Reference</a></li><li class="tocline"><a href="#grammar-language-map" class="tocxref"><span class="secno">A.3 </span>Language Map</a></li><li class="tocline"><a href="#grammar-expanded-values" class="tocxref"><span class="secno">A.4 </span>Expanded Values</a></li><li class="tocline"><a href="#grammar-set-list" class="tocxref"><span class="secno">A.5 </span>List and Set Values</a></li><li class="tocline"><a href="#grammar-context" class="tocxref"><span class="secno">A.6 </span>Context Definition</a></li></ul></li><li class="tocline"><a href="#relationship-to-other-linked-data-formats-and-data-models" class="tocxref"><span class="secno">B. </span>Relationship to Other Linked Data Formats and Data Models</a><ul class="toc"><li class="tocline"><a href="#rdf" class="tocxref"><span class="secno">B.1 </span>RDF</a><ul class="toc"><li class="tocline"><a href="#turtle" class="tocxref"><span class="secno">B.1.1 </span>Turtle</a><ul class="toc"><li class="tocline"><a href="#prefix-definitions" class="tocxref"><span class="secno">B.1.1.1 </span>Prefix definitions</a></li><li class="tocline"><a href="#embedding-1" class="tocxref"><span class="secno">B.1.1.2 </span>Embedding</a></li><li class="tocline"><a href="#lists" class="tocxref"><span class="secno">B.1.1.3 </span>Lists</a></li></ul></li><li class="tocline"><a href="#rdfa" class="tocxref"><span class="secno">B.1.2 </span>RDFa</a></li><li class="tocline"><a href="#microformats" class="tocxref"><span class="secno">B.1.3 </span>Microformats</a></li><li class="tocline"><a href="#microdata" class="tocxref"><span class="secno">B.1.4 </span>Microdata</a></li></ul></li><li class="tocline"><a href="#iana-considerations" class="tocxref"><span class="secno">B.2 </span>IANA Considerations</a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno">B.3 </span>Acknowledgements</a></li></ul></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></section>
+
+
+
+<section class="informative" id="introduction">
+
+<!--OddPage-->
+<h2><span class="secno">1. </span>Introduction</h2><p><em>This section is non-normative.</em></p>
+
+<p>
+JSON, as specified in [<cite><a class="bibref" href="#bib-RFC4627">RFC4627</a></cite>], is a simple language for representing
+data on the Web. <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> is a technique for creating a network
+of inter-connected data across different Web documents and Web sites.
+A <em>document</em> in this data network is typically identified using an
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> (Internationalized Resource Identifier). A software program
+can typically follow an <abbr title="Internationalized Resource Identifier">IRI</abbr> just like you follow a URL by putting it into your
+browser's location bar. By following IRIs, a software program can find
+more information about the <em>document</em> and the <em>thing</em>s that
+the document describes.
+These <em>things</em> may also be identified using <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s. The
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> allows a software program to start at one
+<em>document</em> and follow links to other
+<em>documents</em> or <em>things</em> in order to learn more about all of
+the <em>documents</em> and <em>things</em> described on the Web.
+</p>
+
+<p>
+JSON-LD is designed as a lightweight syntax that can be used to express
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>. It is primarily intended to be a way to use Linked Data
+in Javascript and other Web-based programming environments. It is also
+useful when building inter-operable Web services and when storing Linked
+Data in JSON-based document storage engines. It is practical and designed
+to be as simple as possible, utilizing the large number of JSON parsers
+and libraries available today.
+</p>
+
+<p>
+The syntax does not necessarily require applications to change their JSON, but
+allows one to easily add meaning by simply adding or referencing a context.
+The syntax is designed to not disturb already deployed systems
+running on JSON, but provide a smooth upgrade path from JSON to JSON-LD.
+Finally, the format is intended to be easy to parse, efficient
+to generate, and can operate inside of devices that contain very little
+memory.
+</p>
+
+<section id="how-to-read-this-document">
+<h3><span class="secno">1.1 </span>How to Read this Document</h3><p><em>This section is non-normative.</em></p>
+
+<p>
+This document is a detailed specification for a serialization of Linked
+Data in JSON. The document is primarily intended for the following audiences:
+</p>
+
+<ul>
+ <li>Software developers that want to encode Linked Data in a variety of
+ programing languages that can use JSON.</li>
+ <li>Software developers that want to understand the design decisions and
+ language syntax for JSON-LD.</li>
+ <li>Software developers that want to implement processors and APIs for
+ JSON-LD.</li>
+</ul>
+
+<p>This specification does not describe the programming interfaces for the
+JSON-LD Syntax. The specification that describes the programming interfaces
+for JSON-LD documents is the JSON-LD Application Programming Interface
+[<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>].</p>
+
+<p>
+To understand the basics in this specification you must first be familiar with
+JSON, which is detailed in [<cite><a class="bibref" href="#bib-RFC4627">RFC4627</a></cite>].</p>
+
+</section>
+
+</section>
+
+<section class="informative" id="design-goals-and-rationale">
+
+<!--OddPage-->
+<h2><span class="secno">2. </span>Design Goals and Rationale</h2><p><em>This section is non-normative.</em></p>
+
+<p>A number of design goals were established before the creation of this
+ markup language:</p>
+
+<dl>
+ <dt>Simplicity</dt>
+ <dd>No extra
+ processors or software libraries should be necessary to use JSON-LD in its most
+ basic form. The language will provide developers with a very easy
+ learning curve. Developers need only know JSON and two
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a> (<code>@context</code>
+ and <code>@id</code>) to use the basic functionality in JSON-LD.</dd>
+ <dt>Compatibility</dt>
+ <dd>The JSON-LD markup must be 100% compatible with JSON. This ensures that
+ all of the standard JSON libraries work seamlessly with JSON-LD documents.</dd>
+ <dt>Expressiveness</dt>
+ <dd>The syntax must be able to express directed graphs, which have been proven
+ to be able to express almost every real world data model.</dd>
+ <dt>Terseness</dt>
+ <dd>The JSON-LD syntax must be very terse and human readable, requiring as
+ little effort as possible from the developer.</dd>
+
+<!--<dt>Pragmatism</dt>
+ <dd>Mixing the expression of pure Linked Data with data that is not
+ linked was an approach that was driven by pragmatism. JSON-LD attempts to be
+ more practical than theoretical in its approach to Linked Data.</dd>-->
+
+ <dt>Zero Edits, most of the time</dt>
+ <dd>JSON-LD must provide a
+ <a href="#referencing-contexts-from-json-documents">mechanism</a>
+ that allows developers to specify <a class="tref internalDFN" title="context" href="#dfn-context">context</a> in a way that is
+ out-of-band.
+ This allows organizations that have
+ already deployed large JSON-based infrastructure to add meaning to their
+ JSON documents in a way that is not disruptive to their day-to-day operations and is
+ transparent to their current customers. At times, mapping JSON to
+ a graph representation can become difficult. In these instances, rather than
+ having JSON-LD support an esoteric use case, we chose not to support the
+ use case and support a simplified syntax instead. So, while Zero Edits is
+ a design goal, it is not always possible without adding great complexity to
+ the language.
+ </dd>
+ <dt>One-pass Processing</dt>
+ <dd>JSON-LD supports one-pass processing, which results in a very small memory
+ footprint when processing documents. For example, to expand a JSON-LD document
+ from a compacted form, only one pass is required over the data.</dd>
+ <dt>Linked Data-centric</dt>
+ <dd>The focus on Linked Data is placed at a much higher priority than the
+ focus on the Semantic Web. One outcome of this ordering of
+ priorities is an aggressively reduced focus on the Semantic Web stack
+ (RDF [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>], TURTLE [<cite><a class="bibref" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>], triple stores, and
+ SPARQL [<cite><a class="bibref" href="#bib-RDF-SPARQL-QUERY">RDF-SPARQL-QUERY</a></cite>]).
+ While this may be off-putting to proponents of the Semantic Web, the audience
+ for this specification are Web developers that want a gentler introduction
+ and a simpler technology stack for using Linked Data in their Web applications.
+ Semantic Web concepts, such as conversion to and from RDF, are fully supported
+ by JSON-LD, but the implementation of these features are not elaborated upon
+ in this specification. See <a href="#relationship-to-other-linked-data-formats-and-data-models" class="sec-ref"><span class="secno">B.</span> <span class="sec-title">Relationship to Other Linked Data Formats and Data Models</span></a>
+ for more information about how JSON-LD integrates into the more traditional
+ Semantic Web stack.
+ </dd>
+</dl>
+</section>
+
+<section class="normative" id="basic-concepts">
+
+<!--OddPage-->
+<h2><span class="secno">3. </span>Basic Concepts</h2>
+
+<em>This section is normative.</em>
+
+<p>JSON-LD is designed to ensure that <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> concepts can be
+marked up in a way that is simple to understand and create by Web authors.
+In many cases, regular JSON markup can become Linked Data with the
+simple addition of a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>. As more JSON-LD features are
+used, more semantics are added to the JSON markup.</p>
+
+<section id="benefits-of-json-ld">
+<h3><span class="secno">3.1 </span>Benefits of JSON-LD</h3>
+
+<p>
+JSON provides a number of benefits to software developers that need to
+serialize data:
+</p>
+
+<ol>
+<li>It is easy for humans to read and write.</li>
+<li>It is easy for machines to parse and generate.</li>
+<li>It has a syntax that is familiar across a large number of programming
+ languages.</li>
+<li>It is capable of representing many different types of data using two
+universal data structures; a collection of key-value pairs and lists.</li>
+</ol>
+
+<p>
+JSON has become a very popular data-interchange format on the Web, particularly
+for <a href="http://en.wikipedia.org/wiki/REST">REST</a>-based Web Services.
+Unfortunately, it has a number of short-comings that other Web-native data
+formats do not have:
+</p>
+
+<ol>
+<li>There is no standardized, universal identifier mechanism for
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>s.</li>
+<li>The meaning of the keys used in a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>s are ambiguous and often conflict with other data
+published on the Web.
+</li>
+<li>There is no standardized way for a value in a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> to
+refer to a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> on a different site on the Web.</li>
+<li>A developer cannot express the language associated with a
+<a class="tref internalDFN" title="string" href="#dfn-string">string</a> value in a standardized manner.</li>
+<li>There is no standard mechanism to associate datatypes with values such as
+ dates, times, weights, and distances.</li>
+<li>There is no facility to express a Web of information (directed graph),
+such as a social network, in a standardized manner.</li>
+</ol>
+
+<p>
+JSON-LD is a web-native standard, is 100% compatible with JSON,
+provides all of the facilities that JSON provides, and extends the
+language to provide the following core advantages:
+</p>
+
+<ol>
+<li>A universal identifier mechanism for <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>s via
+the use of <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s.</li>
+<li>A way to dis-ambiguate the keys used between multiple JSON documents
+by mapping them to <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s via a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>.
+</li>
+<li>A mechanism in which a value in a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> may
+refer to a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> on a different site on the Web.</li>
+<li>The ability to express the language associated with a
+<a class="tref internalDFN" title="string" href="#dfn-string">string</a> value.</li>
+<li>A way to associate datatypes with values such as dates, times,
+ weights, and distances.</li>
+<li>A facility to express one or more directed graphs, such as a social
+network, in a single document.</li>
+</ol>
+
+<p>
+Developers that require any of the facilities listed above will find
+JSON-LD of interest.
+</p>
+
+</section>
+
+<section id="json-ld-data-model">
+<h3><span class="secno">3.2 </span>JSON-LD Data Model</h3>
+
+<p>
+<dfn title="linked_data" id="dfn-linked_data">Linked Data</dfn> is a way of publishing data on the Web. In general,
+Linked Data has four properties; 1) It uses <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s to name
+<em>things</em>, 2) It uses HTTP <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s for those names, 3) The
+name links, when followed, provide more information about the name, and
+4) The data expresses links to data on other Web sites. These properties
+allow data published on the Web to work much like Web pages do today. One
+can start at one piece of Linked Data, and follow the links to other pieces
+of data that are hosted on different sites across the Web.
+</p>
+
+<p>
+JSON-LD is a way of expressing <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> on the Web. The
+JSON-LD data model encapsulates the following concepts:
+</p>
+
+<ol>
+ <li>The JSON-LD data model is used to represent <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a>s.</li>
+ <li>A <dfn title="linked_data_graph" id="dfn-linked_data_graph">linked data graph</dfn> is an unordered labeled directed graph, where each <dfn title="node" id="dfn-node">node</dfn> is a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> or <a class="tref internalDFN" title="object" href="#dfn-object">object</a>, and edges are labeled using <a class="tref internalDFN" title="property" href="#dfn-property">properties</a>.</li>
+ <li>A <dfn title="subject" id="dfn-subject">subject</dfn> is any node in a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> with at least one outgoing edge.</li>
+ <li>A <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> <em class="rfc2119" title="should">should</em> be labeled with an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> (an Internationalized Resource Identifier as described in [<cite><a class="bibref" href="#bib-RFC3987">RFC3987</a></cite>]).</li>
+ <li>An <dfn title="object" id="dfn-object">object</dfn> is a node in a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> with at least one incoming edge.</li>
+ <li>An <a class="tref internalDFN" title="object" href="#dfn-object">object</a> <em class="rfc2119" title="may">may</em> be labeled with an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or a label that is not an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> such as plain text, internationalized text, or a strictly-typed data value.</li>
+ <li>A <a class="tref internalDFN" title="node" href="#dfn-node">node</a> <em class="rfc2119" title="may">may</em> be a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> and an <a class="tref internalDFN" title="object" href="#dfn-object">object</a> at the same time.</li>
+ <li>A <dfn title="property" id="dfn-property">property</dfn> is the label on an edge in a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a>.</li>
+ <li>A <a class="tref internalDFN" title="property" href="#dfn-property">property</a> <em class="rfc2119" title="should">should</em> be an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</li>
+ <li>An <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> that is a label in a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> <em class="rfc2119" title="should">should</em> be dereferencable to a <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> document describing the labeled <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a>, <a class="tref internalDFN" title="property" href="#dfn-property">property</a> or <a class="tref internalDFN" title="object" href="#dfn-object">object</a>.</li>
+</ol>
+
+<div class="note"><div class="note-title"><span>Note</span></div><div class="">
+ <p>
+A <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> document does not necessarily need to be expressed
+in JSON-LD. The notion of <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> is a concept independent of
+any given serialization format.
+ </p>
+</div></div>
+
+<img style="padding: 5px; border-style: solid; border-width: 1px; display: block; margin-left: auto; margin-right: auto;" src="linked-data-graph.png" title="An example of a linked data graph" longdesc="An example of a linked data graph showing two main nodes labeled with URLs for Alice and Bob. The Alice node contains two other connected nodes showing Alice's age (32) and name (Alice)." />
+<p style="text-align: center;">
+Figure 1: An example of a linked data graph.
+</p>
+<p>There are a number of best practices that can ensure that developers
+will generate good Linked Data for the Web. JSON-LD
+formalizes those techniques by providing a mechanism to map JSON data,
+i.e., keys and values, to <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s. This does not mean
+that JSON-LD requires every key or value to be an <abbr title="Internationalized Resource Identifier">IRI</abbr>, but rather ensures that
+keys and values can be mapped to IRIs if the developer desires to transform
+their data into <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>.
+</p>
+
+</section>
+
+<section id="general-terminology">
+ <h3><span class="secno">3.3 </span>General Terminology</h3>
+
+ <p>The following is an explanation of the general terminology used in this
+ document. Many of the terms should be familiar to developers that have
+ used JSON:</p>
+
+ <dl>
+ <dt><dfn title="json_object" id="dfn-json_object">JSON object</dfn></dt><dd>
+ An object structure is represented as a pair of curly brackets
+ surrounding zero or more key-value pairs. A key is a
+ <a class="tref internalDFN" title="string" href="#dfn-string">string</a>. A single colon comes after each key, separating the
+ key from the value. A single comma separates a value from a following
+ key. The keys within an object <em class="rfc2119" title="should">should</em> be unique.
+ </dd>
+ <dt><dfn title="array" id="dfn-array">array</dfn></dt>
+ <dd>
+ In JSON, an array is an <em>ordered</em> sequence of zero or more values.
+ An array is represented as square brackets surrounding
+ zero or more values that are separated by commas.
+ While JSON-LD uses the same array representation as JSON,
+ the collection is <em>unordered</em> by default. While order is
+ preserved in regular JSON arrays, it is not in regular JSON-LD arrays
+ unless specific markup is provided
+ (see <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>).</dd>
+ <dt><dfn title="string" id="dfn-string">string</dfn></dt><dd>
+ A string is a sequence of zero or more Unicode characters,
+ wrapped in double quotes, using backslash escapes (if necessary). A
+ character is represented as a single character string.</dd>
+ <dt><dfn title="number" id="dfn-number">number</dfn></dt>
+ <dd>
+ A number is similar to that used in most programming languages, except
+ that the octal and hexadecimal formats are not used and that leading
+ zeros are not allowed.</dd>
+ <dt><dfn title="true" id="dfn-true">true</dfn> and <dfn title="false" id="dfn-false">false</dfn></dt><dd>
+ Values that are used to express one of two possible boolean states.</dd>
+ <dt><dfn title="null" id="dfn-null">null</dfn></dt><dd>
+ The null value is used to make a JSON-LD processor "forget" any
+ previously defined JSON key that is associated with the null value.
+ If a previous definition doesn't exist, the entire key-value is ignored.
+ If a previous definition of the key does exist, the previous
+ definition is undefined.</dd>
+ <dt><dfn title="node_definition" id="dfn-node_definition">node definition</dfn></dt><dd>
+ A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> used to represent a <a class="tref internalDFN" title="node" href="#dfn-node">node</a> and
+ one or more properties of that node. A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is a
+ node definition if it does not contain the keys <code>@value</code>,
+ <code>@list</code> or <code>@set</code> and it has one or more keys other
+ than <code>@id</code>. A node definition <em class="rfc2119" title="may">may</em> be spread among different
+ parts of a document or even between different documents.</dd>
+ <dt><dfn title="node_reference" id="dfn-node_reference">node reference</dfn></dt><dd>
+ A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> used to refer to a node that contains a
+ single key-value pair where the key is <code>@id</code>.</dd>
+ </dl>
+<p></p>
+
+</section>
+
+<section id="syntax-tokens-and-keywords">
+<h3><span class="secno">3.4 </span>Syntax Tokens and Keywords</h3>
+
+<p>JSON-LD specifies a number of syntax tokens and <dfn title="keyword" id="dfn-keyword">keywords</dfn>
+that are a core part of the language:</p>
+
+<dl>
+<dt><code>@context</code></dt>
+<dd>Used to define the short-hand names that are used throughout a JSON-LD
+ document. These short-hand names are called <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s and help
+ developers to express specific identifiers in a compact manner. The
+ <code>@context</code> keyword is described in detail in the section titled
+ <a href="#the-context" class="sec-ref"><span class="secno">3.5</span> <span class="sec-title">The Context</span></a>.</dd>
+<dt><code>@graph</code></dt><dd>Used to explicitly label a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a>.
+ This keyword is described in <a href="#named-graphs" class="sec-ref"><span class="secno">4.11</span> <span class="sec-title">Named Graphs</span></a>.</dd>
+<dt><code>@id</code></dt>
+<dd>Used to uniquely identify <em>things</em> that are being described in the document.
+ This keyword is described in <a href="#node-identifiers" class="sec-ref"><span class="secno">3.8</span> <span class="sec-title">Node Identifiers</span></a>.</dd>
+<dt><code>@value</code></dt>
+<dd>Used to specify the data that is associated with a particular
+ <a class="tref internalDFN" title="property" href="#dfn-property">property</a> in the graph. This keyword is described in
+ <a href="#string-internationalization" class="sec-ref"><span class="secno">3.10</span> <span class="sec-title">String Internationalization</span></a> and
+ <a href="#typed-values" class="sec-ref"><span class="secno">4.2</span> <span class="sec-title">Typed Values</span></a>.</dd>
+<dt><code>@language</code></dt>
+<dd>Used to specify the native language for a particular value or the default
+ language of a JSON-LD document. This keyword is described in the section titled
+ <a href="#string-internationalization" class="sec-ref"><span class="secno">3.10</span> <span class="sec-title">String Internationalization</span></a>.</dd>
+<dt><code>@type</code></dt>
+<dd>Used to set the data type of a <a class="tref internalDFN" title="node" href="#dfn-node">node</a> or
+ <a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>. This keyword is described in the section titled
+ <a href="#typed-values" class="sec-ref"><span class="secno">4.2</span> <span class="sec-title">Typed Values</span></a>.</dd>
+<dt><code>@container</code></dt>
+<dd>Used to set the container of a particular value.
+ This keyword is described in the section titled <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>.</dd>
+<dt><code>@list</code></dt>
+<dd>Used to express an ordered set of data.
+ This keyword is described in the section titled <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>.</dd>
+<dt><code>@set</code></dt>
+<dd>Used to express an unordered set of data.
+ This keyword is described in the section titled <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>.</dd>
+<dt><code>@vocab</code></dt>
+<dd>Used to set the base <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> for all property IRIs affected by the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>. This keyword is described in section <a href="#iris" class="sec-ref"><span class="secno">3.7</span> <span class="sec-title">IRIs</span></a>.</dd>
+<dt><code>:</code></dt>
+<dd>The separator for JSON keys and values that use
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact IRIs</a>.</dd>
+</dl>
+
+<p>For the avoidance of doubt, all keys, <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a>, and values in JSON-LD are
+case-sensitive.</p>
+</section>
+
+<section id="the-context">
+<h3><span class="secno">3.5 </span>The Context</h3>
+
+<p>In JSON-LD, a <dfn title="context" id="dfn-context">context</dfn> is used to map <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s, i.e., properties with associated
+ values in an JSON document, to <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s. A <dfn title="term" id="dfn-term">term</dfn> is a short word that expands to an
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>. <a class="tref internalDFN" title="term" href="#dfn-term">Term</a>s <em class="rfc2119" title="may">may</em> be defined as any valid JSON <a class="tref internalDFN" title="string" href="#dfn-string">string</a> other
+ than a JSON-LD <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. To avoid
+ forward-compatibility issues, <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s starting with an <code>@</code> character <em class="rfc2119" title="should not">should not</em> be used
+ as they might be used as <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a> in future versions of JSON-LD. Furthermore,
+ the use of empty terms (<code>""</code>) is discouraged as not all programming languages are able to handle
+ empty property names.</p>
+<p>The Web uses <a class="tref internalDFN" title="iri" href="#dfn-iri">IRIs</a> for unambiguous identification. The
+ idea is that these <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s mean something that may be of use to other developers and that it is useful to
+ give them an unambiguous identifier. That is, it is useful for <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s to expand to IRIs so that
+ developers don't accidentally step on each other's <dfn title="vocabulary" id="dfn-vocabulary">vocabulary</dfn> terms and other resources. Furthermore, developers, and
+ machines, are able to use this <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> (by plugging it directly into a web browser, for instance) to go to
+ the term and get a definition of what the term means. This mechanism is analogous to the way we can use
+ <a href="http://wordnet.princeton.edu/">WordNet</a> today to see the definition of words in the English language.
+ Developers and machines need the same sort of definition of terms. <a class="tref internalDFN" title="iri" href="#dfn-iri">IRIs</a> provide a way to
+ ensure that these terms are unambiguous. For example, the term <code>name</code> may
+ map directly to the <abbr title="Internationalized Resource Identifier">IRI</abbr> <code>http://xmlns.com/foaf/0.1/name</code>. This allows JSON-LD documents to be constructed
+ using the common JSON practice of simple key-value pairs while ensuring that the data is useful outside of the
+ page, API or database in which it resides. The value of a term mapping
+ <em class="rfc2119" title="must">must</em> be either; 1) a simple string with the lexical form of an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> or
+ 2) <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or 3) an <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> containing an
+ <code>@id</code>, <code>@type</code>, <code>@language</code>, or <code>@container</code> keyword
+ (all other keywords are ignored by a JSON-LD processor).
+</p>
+
+<p>These Linked Data <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s are typically collected in a
+context document that would look something like this:</p>
+
+<div class="example"><div class="example-title"><span>Example 1</span>: Context definition</div><pre class="example">{
+ "@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "depiction":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/depiction",
+ "@type": "@id"
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ },
+ }
+}</pre></div>
+
+<p>
+Let's assume that a developer starts with the following JSON document:
+</p>
+
+<div class="example"><div class="example-title"><span>Example 2</span>: Sample JSON object</div><pre class="example">{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>The developer can add a single line to the JSON document above
+to reference the context and transform it into a JSON-LD document:</p>
+
+<div class="example"><div class="example-title"><span>Example 3</span>: Adding context reference to JSON document</div><pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person.jsonld",</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>The additions above transform the previous JSON document into a JSON document
+with added semantics because the <code>@context</code> specifies how the
+<strong>name</strong>, <strong>homepage</strong>, and <strong>depiction</strong>
+terms map to <a class="tref internalDFN" title="iri" href="#dfn-iri">IRIs</a>.
+Mapping those keys to IRIs gives the data global context. If two
+developers use the same <abbr title="Internationalized Resource Identifier">IRI</abbr> to describe a property, they are more than likely
+expressing the same concept. This allows both developers to re-use each others'
+data without having to agree to how their data will interoperate on a
+site-by-site basis. Contexts may also contain type information
+for certain <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s as well as other processing instructions for
+the JSON-LD processor.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">External JSON-LD context documents <em class="rfc2119" title="may">may</em> contain extra information
+located outside of the <code>@context</code> key, such as documentation about the
+<a class="tref internalDFN" title="term" href="#dfn-term">terms</a> declared in the document. When importing a
+<code>@context</code> value from an external JSON-LD context document, any extra
+information contained outside of the <code>@context</code> value <em class="rfc2119" title="must">must</em> be discarded.</p></div>
+
+<p>Contexts <em class="rfc2119" title="may">may</em> be specified in-line. This ensures that JSON-LD documents
+can be processed when a JSON-LD processor does not have access to the Web.</p>
+
+<div class="example"><div class="example-title"><span>Example 4</span>: In-line context definition</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "depiction":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/depiction",
+ "@type": "@id"
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ },
+ },</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>Contexts <em class="rfc2119" title="may">may</em> be used at any time a <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> is defined.
+ A <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> <em class="rfc2119" title="may">may</em> specify multiple contexts, using an
+ <a class="tref internalDFN" title="array" href="#dfn-array">array</a>, which is processed in order. This is useful
+ when an author would like to use an existing context and add
+ application-specific terms to the existing context. Duplicate context
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s <em class="rfc2119" title="must">must</em> be overridden using a last-defined-overrides
+ mechanism.</p>
+
+<div class="example"><div class="example-title"><span>Example 5</span>: Scoped contexts within node definitions</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "name": "http://example.com/person#name",
+ "details": "http://example.com/person#details"
+ },</span>
+ "<span class="diff">name</span>": "Markus Lanthaler",
+ ...
+ "details":
+ {
+ <span class="diff">"@context": {
+ "name": "http://example.com/organization#name"
+ },</span>
+ "<span class="diff">name</span>": "Graz University of Technology"
+ }
+}</pre></div>
+
+<p>In the example above, the <code>name</code> prefix is overridden in the
+ more deeply nested <code>details</code> structure. Note that this is
+ rarely a good authoring practice and is typically used when there exist
+ legacy applications that depend on the specific structure of the
+ <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">If a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> is re-defined within a context, all previous
+ rules associated with the previous definition are removed. A <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined
+ in a previous context <em class="rfc2119" title="must">must</em> be removed, if it is re-defined to <code>null</code>.</p></div>
+
+<p>The set of contexts defined within a specific <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> are
+ referred to as <dfn title="local_context" id="dfn-local_context">local context</dfn>s. Setting the context to <code>null</code>
+ effectively resets the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> to an empty context. The
+ <dfn title="active_context" id="dfn-active_context">active context</dfn> refers to the accumulation of <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a>s
+ that are in scope at a specific point within the document. The following example
+ specifies an external context and then layers a local context on top of the external
+ context:</p>
+
+<div class="example"><div class="example-title"><span>Example 6</span>: Combining external and local contexts</div><pre class="example">{
+ <span class="diff">"@context": [
+ "http://json-ld.org/contexts/person.jsonld",
+ {
+ "pic": "http://xmlns.com/foaf/0.1/depiction"
+ }
+ ],</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ <span class="diff">"pic": "http://twitter.com/account/profile_image/manusporny"</span>
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">To ensure the best possible performance, it is a best practice to
+ put the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition at the top of the JSON-LD document. If it isn't listed
+ first, processors have to save each key-value pair until the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> is processed.
+ This creates a memory and complexity burden for certain types of
+ low-memory footprint JSON-LD processors.</p></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">The <code>null</code> value is processed in a special way
+ in JSON-LD. Unless otherwise specified, a JSON-LD processor <em class="rfc2119" title="must">must</em> act as if a
+ key-value pair in the body of a JSON-LD document was never declared when
+ the value equals <em>null</em>. If <code>@value</code>, <code>@list</code>,
+ or <code>@set</code> is set to <em>null</em> in expanded form, then the
+ entire <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is ignored. If <code>@context</code> is set
+ to <em>null</em>, the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> is reset and when used
+ within a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>, it removes any definition associated with
+ the key, unless otherwise specified.</p></div>
+
+</section>
+
+<section id="from-json-to-json-ld">
+<h3><span class="secno">3.6 </span>From JSON to JSON-LD</h3>
+
+<p>If a set of <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s such as, <strong>name</strong>,
+<strong>homepage</strong>, and <strong>depiction</strong>,
+are defined in a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>, and that context is used to resolve the
+names in <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON objects</a>, machines are able to automatically expand the terms to
+something meaningful and unambiguous, like this:</p>
+
+<div class="example"><div class="example-title"><span>Example 7</span>: Expanded terms</div><pre class="example">{
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+ "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>": "http://manu.sporny.org"
+ "<span class="diff">http://xmlns.com/foaf/0.1/depiction</span>": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>Doing this allows JSON to be unambiguously machine-readable without
+requiring developers to drastically change their workflow.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">The example above does not use the <code>@id</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>
+to identify the node being described above. This type of node is called an
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a>. It is advised that all nodes described in JSON-LD are
+given unique identifiers via the <code>@id</code> keyword unless the data is not
+intended to be linked to from other data sets.</p></div>
+
+<p>A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> used to define property values is called a
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>. <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">Node definitions</a>
+ do not require an <code>@id</code>.
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">Node definitions</a> that do not
+ contain an <code>@id</code> are known as an <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled nodes</a>.</p>
+
+</section>
+
+<section id="iris">
+<h3><span class="secno">3.7 </span>IRIs</h3>
+
+<p><a class="tref internalDFN" title="iri" href="#dfn-iri">IRIs</a> are fundamental to <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>
+as that is how most <a class="tref internalDFN" title="node" href="#dfn-node">nodes</a>s and all
+<a class="tref internalDFN" title="property" href="#dfn-property">properties</a> are
+identified. <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s can be expressed in a variety of different ways
+in JSON-LD.</p>
+
+<p>An <dfn title="iri" id="dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></dfn>
+ (an Internationalized Resource Identifier) is described in [<cite><a class="bibref" href="#bib-RFC3987">RFC3987</a></cite>])
+ and the use with JSON-LD conforms to the definition of
+ <cite><a href="http://www.w3.org/TR/rdf11-concepts/#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a></cite> in [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>].</p>
+
+<ol>
+ <li>Except within a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition, <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s in the key position in
+ a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> that have a mapping or a vocabulary base <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> in the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> are expanded to an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> by JSON-LD processors.</li>
+ <li>An <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is generated for the <a class="tref internalDFN" title="string" href="#dfn-string">string</a> value specified using
+ <code>@id</code> or <code>@type</code>.</li>
+ <li>An <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is generated for the <a class="tref internalDFN" title="string" href="#dfn-string">string</a> value of any key for which there
+ are <a class="tref internalDFN" title="coercion" href="#dfn-coercion">coercion</a> rules in effect that identify the value as an <code>@id</code>.</li>
+</ol>
+
+<p>IRIs may be represented as an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, a <a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">relative <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, a <a class="tref internalDFN" title="term" href="#dfn-term">term</a>,
+ a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or as a value relative to <code>@vocab</code>.</p>
+
+<p>An <dfn title="absolute_iri" id="dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></dfn> is defined in [<cite><a class="bibref" href="#bib-RFC3987">RFC3987</a></cite>] containing a <em>scheme</em> along with
+ <em>path</em> and optional <em>query</em> and <em>fragment</em> segments. A <dfn title="relative_iri" id="dfn-relative_iri">relative <abbr title="Internationalized Resource Identifier">IRI</abbr></dfn> is an <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ that is relative to some other <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>. In JSON-LD all <a class="tref internalDFN" title="relative_iri" href="#dfn-relative_iri">relative <abbr title="Internationalized Resource Identifier">IRI</abbr></a>s are resolved relative to the
+ <dfn title="base_iri" id="dfn-base_iri">base <abbr title="Internationalized Resource Identifier">IRI</abbr></dfn> associated with the document (typically, the directory that contains the document or the document itself).</p>
+
+<p>IRIs can be expressed directly in the key position like so:</p>
+
+<div class="example"><div class="example-title"><span>Example 8</span>: IRI as a key</div><pre class="example">{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}</pre></div>
+
+<p>In the example above, the key <code>http://xmlns.com/foaf/0.1/name</code> is interpreted
+ as an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> because it contains a colon
+ (<code>:</code>) and the 'http' <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> does not exist in
+ the context.</p>
+
+<p>Term expansion occurs for IRIs if the value matches a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined within the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>:</p>
+
+<div class="example"><div class="example-title"><span>Example 9</span>: Term expansion from context definition</div><pre class="example">{
+ "<span class="diff">@context</span>":
+ {
+ "<span class="diff">name</span>": "<span class="diff">http://xmlns.com/foaf/0.1/name</span>"
+...
+ },
+ "<span class="diff">name</span>": "Manu Sporny",
+ "status": "trollin'",
+...
+}</pre></div>
+
+<p><a class="tref internalDFN" title="term" href="#dfn-term">Term</a>s are case sensitive, and <em class="rfc2119" title="must">must</em> be matched using a case-sensitive comparison.</p>
+
+<p>JSON keys that do not expand to an absolute <abbr title="Internationalized Resource Identifier">IRI</abbr> are ignored, or removed
+in some cases, by the [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>]. However, JSON keys that do not include
+a mapping in the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> are still considered valid expressions
+in JSON-LD documents - the keys just don't have any machine-readable,
+semantic meaning.</p>
+
+<p><a class="tref internalDFN" title="prefix" href="#dfn-prefix">Prefix</a>es are expanded when the form of the value is a
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> represented as a <code>prefix:suffix</code>
+ combination, and the prefix matches a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined within the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>:</p>
+
+<div class="example"><div class="example-title"><span>Example 10</span>: Prefix expansion</div><pre class="example">{
+ "<span class="diff">@context</span>":
+ {
+ "<span class="diff">foaf</span>": "<span class="diff">http://xmlns.com/foaf/0.1/</span>"
+...
+ },
+ "<span class="diff">foaf:name</span>": "Manu Sporny",
+...
+}</pre></div>
+
+<p><code>foaf:name</code> above will automatically expand out to the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+<code>http://xmlns.com/foaf/0.1/name</code>. See <a href="#compact-iris" class="sec-ref"><span class="secno">4.1</span> <span class="sec-title">Compact IRIs</span></a> for more details.</p>
+
+<p>If the <code>@vocab</code> is set, all keys that do not match a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> or a <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>
+ are
+
+
+It is often common that all types and properties come from the same vocabulary. JSON-LD's
+<code>@vocab</code> keyword allows to set a base <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> to be used for all properties and types
+that that do not match a <a class="tref internalDFN" title="term" href="#dfn-term">term</a>, a <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>, or an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+(i.e., do not contain a colon). The <code>@vocab</code> mapping <em class="rfc2119" title="must">must</em> have a value of a simple string with the
+lexical form of an absolute <abbr title="Internationalized Resource Identifier">IRI</abbr>.</p>
+
+<div class="example"><div class="example-title"><span>Example 11</span>: Vocabulary base IRI</div><pre class="example">{
+ <span class="diff">"@context": {
+ "@vocab": "http://xmlns.com/foaf/1.0/"
+ },</span>
+ "@type": <span class="diff">"Person"</span>,
+ <span class="diff">"name"</span>: "Manu Sporny",
+}</pre></div>
+
+<p>An <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is generated when a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is used in the
+ value position that contains an <code>@id</code> keyword:</p>
+
+<div class="example"><div class="example-title"><span>Example 12</span>: Expanded IRI definition</div><pre class="example">{
+...
+ "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
+...
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">Specifying a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> with an
+ <code>@id</code> key is used to identify that <a class="tref internalDFN" title="node" href="#dfn-node">node</a> using an
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>. When the object has only the <code>@id</code>, it
+ is called a <a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>.
+ This facility <em class="rfc2119" title="may">may</em> also be used to link to another
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> using a mechanism called
+ <a class="tref internalDFN" title="embedding" href="#dfn-embedding">embedding</a>, which is covered in the section titled
+ <a href="#embedding" class="sec-ref"><span class="secno">4.10</span> <span class="sec-title">Embedding</span></a>.</p></div>
+
+<p>If type <a class="tref internalDFN" title="coercion" href="#dfn-coercion">coercion</a> rules are specified in the <code>@context</code> for
+a particular <a class="tref internalDFN" title="term" href="#dfn-term">term</a> or property <abbr title="Internationalized Resource Identifier">IRI</abbr>, an <abbr title="Internationalized Resource Identifier">IRI</abbr> is generated:</p>
+
+<div class="example"><div class="example-title"><span>Example 13</span>: Type coercion</div><pre class="example">{<span class="diff">
+ "@context":
+ {
+ ...
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ ...
+ }</span>
+...
+ "homepage": "http://manu.sporny.org/",
+...
+}</pre></div>
+
+<p>In the example above, even though the value
+<code>http://manu.sporny.org/</code> is expressed as a JSON
+<a class="tref internalDFN" title="string" href="#dfn-string">string</a>, the type <a class="tref internalDFN" title="coercion" href="#dfn-coercion">coercion</a> rules will transform
+the value into an <abbr title="Internationalized Resource Identifier">IRI</abbr> when processed by a JSON-LD Processor.</p>
+
+</section>
+
+<section id="node-identifiers">
+<h3><span class="secno">3.8 </span>Node Identifiers</h3>
+
+<p>To be able to externally reference nodes in a graph, it is important that each node has
+ an unambiguous identifier. <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s are a fundamental concept of
+ <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>, and nodes should have a de-referencable
+ identifier used to name and locate them. For nodes to be truly linked,
+ de-referencing the identifier should result in a representation of that node
+ (for example, using a URL to retrieve a web page).
+ Associating an <abbr title="Internationalized Resource Identifier">IRI</abbr> with a node tells an application that the returned
+ document contains a description of the node requested.</p>
+
+<p>JSON-LD documents may also contain descriptions of other nodes, so it is necessary to be able to
+ uniquely identify each node which may be externally referenced.</p>
+
+<p>The node of a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is identified using the <code>@id</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>:</p>
+
+<div class="example"><div class="example-title"><span>Example 14</span>: Identifying a node</div><pre class="example">{
+ "@context":
+ {
+ ...
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ ...
+ },
+ "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
+ "homepage": "http://manu.sporny.org/",
+...
+}</pre></div>
+
+<p>The example above contains a node identified by the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+ <code>http://example.org/people#joebob</code>.</p>
+
+<p>A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> used to define property values is called a
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>. <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">Node definitions</a>
+ do not require an <code>@id</code>. A <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>
+ that does not contain an <code>@id</code> property defines properties of an
+ <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a>. <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">Node definitions</a> <em class="rfc2119" title="may">may</em>
+ be spread among different parts of a document or even between different documents.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">To ensure the best possible performance, when possible, it is a best practice
+ to put JSON-LD <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>s, such as <code>@id</code> and
+ <code>@context</code> before other key-value pairs in a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>.
+ However, keys in a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> are not ordered,
+ so processors <em class="rfc2119" title="must not">must not</em> depend on key ordering. If keywords are not listed
+ first, processors have to save each key-value pair until at least the
+ <code>@context</code> and the <code>@id</code> are processed. Not
+ specifying those keywords first creates a memory and complexity burden for
+ low-memory footprint processors, forcing them to use more memory and
+ computing cycles than necessary.</p></div>
+
+
+</section>
+
+<section id="specifying-the-type">
+<h3><span class="secno">3.9 </span>Specifying the Type</h3>
+
+<p>The type of a particular node can be specified using the <code>@type</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. To be considered <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>, types <em class="rfc2119" title="must">must</em>
+ be uniquely identified by an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</p>
+
+<div class="example"><div class="example-title"><span>Example 15</span>: Specifying the type for a node</div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "<span class="diff">@type</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+...
+}</pre></div>
+
+<p>A node can be assigned more than one type by using the following markup
+pattern:</p>
+
+<div class="example"><div class="example-title"><span>Example 16</span>: Specifying multiple types for a node</div><pre class="example">{
+...
+ "@id": "http://example.org/places#BrewEats",
+ "<span class="diff">@type</span>": <span class="diff">["http://schema.org/Restaurant", "http://schema.org/Brewery"]</span>
+...
+}</pre></div>
+
+
+</section>
+
+<section id="string-internationalization">
+<h3><span class="secno">3.10 </span>String Internationalization</h3>
+
+<p>At times, it is important to annotate a <a class="tref internalDFN" title="string" href="#dfn-string">string</a>
+ with its language. In JSON-LD this is possible in a variety of ways.
+ Firstly, it is possible to define a default language for a JSON-LD document
+ by setting the <code>@language</code> key in the <code>@context</code> or in a
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a> definition:</p>
+
+<div class="example"><div class="example-title"><span>Example 17</span>: String Internationalization</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ ...
+ "@language": "ja"
+ },</span>
+ "name": <span class="diff">"花澄"</span>,
+ "occupation": <span class="diff">"科学者"</span>
+}</pre></div>
+
+<p>The example above would associate the <code>ja</code> language
+ code with the two <a class="tref internalDFN" title="string" href="#dfn-string">string</a>s <em>花澄</em> and <em>科学者</em>.
+ Languages <em class="rfc2119" title="must">must</em> be well-formed language tags according to [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>].</p>
+
+<p>It is possible to override the default language by using the expanded
+form of a value:</p>
+
+<div class="example"><div class="example-title"><span>Example 18</span>: Expanded value with language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": "花澄",
+ "occupation": <span class="diff">{
+ "@value": "Scientist",
+ "@language": "en"
+ }</span>
+}</pre></div>
+
+<p>It is also possible to override the default language or specify a plain
+value by omitting the <code>@language</code> tag or setting it to
+<code>null</code> when expressing the expanded value:</p>
+
+<div class="example"><div class="example-title"><span>Example 19</span>: Expanded value to remove language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": <span class="diff">{
+ "@value": "Frank"
+ },</span>
+ "occupation": <span class="diff"> {
+ "@value": "Ninja",
+ "@language": "en"
+ }</span>,
+ "speciality": "手裏剣"
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">Please note that language associations <em class="rfc2119" title="must">must</em> only be applied
+ to plain literal <a class="tref internalDFN" title="string" href="#dfn-string">string</a>s. That is, <a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>s
+ or values that are subject to <a href="#type-coercion" class="sec-ref"><span class="secno">4.6</span> <span class="sec-title">Type Coercion</span></a>
+ won't be language tagged.</p></div>
+
+<p>To clear the default language for a subtree, <code>@language</code> can
+be set to <code>null</code> in a <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> as follows:</p>
+
+<div class="example"><div class="example-title"><span>Example 20</span>: Clearing default language</div><pre class="example">{
+ "@context": {
+ ...
+ "@language": "ja"
+ },
+ "name": "花澄",
+ "details": {
+<span class="diff"> "@context": {
+ "@language": null
+ },</span>
+ "occupation": "Ninja"
+ }
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">JSON-LD allows one to associate language information with
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s.
+ See <a href="#expanded-term-definition" class="sec-ref"><span class="secno">4.5</span> <span class="sec-title">Expanded Term Definition</span></a> for
+ more details.</p></div>
+
+</section>
+
+<section id="json-ld-syntax">
+ <h3><span class="secno">3.11 </span>JSON-LD Syntax</h3>
+
+ <p>A JSON-LD document is first, and foremost, a JSON document
+ (as defined in [<cite><a class="bibref" href="#bib-RFC4627">RFC4627</a></cite>]), and any syntactically correct JSON document
+ <em class="rfc2119" title="must">must</em> be processed by a conforming JSON-LD processor. However, JSON-LD
+ describes a specific syntax to use for expressing Linked Data. This
+ includes the use of specific keywords, as identified in <a href="#syntax-tokens-and-keywords" class="sec-ref"><span class="secno">3.4</span> <span class="sec-title">Syntax Tokens and Keywords</span></a> for
+ expressing <a title="node definition">node definitions</a>, values,
+ and the <a href="#dfn-context" class="internalDFN">context</a>. See <a href="#json-ld-grammar" class="sec-ref"><span class="secno">A.</span> <span class="sec-title">JSON-LD Grammar</span></a> for authoring
+ guidelines and a BNF description of JSON-LD.</p>
+
+</section>
+</section>
+
+<section id="advanced-concepts">
+
+<!--OddPage-->
+<h2><span class="secno">4. </span>Advanced Concepts</h2>
+
+<em>This section is normative.</em>
+
+<p>JSON-LD has a number of features that provide functionality above and beyond
+the core functionality described above. The following section describes this
+advanced functionality in more detail.
+</p>
+
+<section id="compact-iris">
+ <h3><span class="secno">4.1 </span>Compact IRIs</h3>
+ <p>
+ <a class="tref internalDFN" title="term" href="#dfn-term">Term</a>s in <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> documents may draw from
+ a number of different <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a>.
+ At times, declaring every single <a class="tref internalDFN" title="term" href="#dfn-term">term</a> that a document uses can require the
+ developer to declare tens, if not hundreds of potential
+ <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s that are used across an
+ application. This is a concern for at least two reasons: the
+ first is the cognitive load on the developer of remembering all of the
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s, and the second is the serialized size of the
+ <a class="tref internalDFN" title="context" href="#dfn-context">context</a> if it is specified inline. In order to address these issues,
+ the concept of a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> is introduced.</p>
+ <p>
+ A <dfn title="compact_iri" id="dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></dfn> is a way of expressing an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ using a <em>prefix</em> and <em>suffix</em> separated by a colon (<code>:</code>) which is
+ similar to the <cite><a href="http://www.w3.org/TR/rdfa-core/#s_curies">CURIE Syntax</a></cite>
+ in [<cite><a class="bibref" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>]. The <dfn title="prefix" id="dfn-prefix">prefix</dfn> is a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> taken from the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> and is a short string identifying a
+ particular <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> in a JSON-LD document.
+ For example, the prefix <code>foaf</code> may be used as a short
+ hand for the Friend-of-a-Friend vocabulary, which is identified using
+ the <abbr title="Internationalized Resource Identifier">IRI</abbr> <code>http://xmlns.com/foaf/0.1/</code>. A developer may append
+ any of the FOAF <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> terms to the end of the prefix
+ to specify a short-hand version of the <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> for the
+ <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> term. For example, <code>foaf:name</code> would
+ be expanded out to the <abbr title="Internationalized Resource Identifier">IRI</abbr> <code>http://xmlns.com/foaf/0.1/name</code>.
+ Instead of having to remember and type out the entire <abbr title="Internationalized Resource Identifier">IRI</abbr>, the developer
+ can instead use the prefix in their JSON-LD markup.
+ </p>
+ <p>Terms are interpreted as <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>s if they contain at least one
+ colon and the first colon is not followed by two slashes (<code>//</code>, as in
+ <code>http://example.com</code>). To generate the full <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ the value is first split into a <em>prefix</em> and <em>suffix</em> at the first
+ occurrence of a colon (<code>:</code>). If the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>
+ contains a term mapping for <em>prefix</em>, an <abbr title="Internationalized Resource Identifier">IRI</abbr> is generated by
+ prepending the mapped <em>prefix</em> to the (possibly empty) <em>suffix</em>
+ using textual concatenation. If no prefix mapping is defined, the value is interpreted
+ as an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>. If the prefix is an underscore
+ (<code>_</code>), the <abbr title="Internationalized Resource Identifier">IRI</abbr> remains unchanged. This effectively means that every term
+ containing a colon will be interpreted by a JSON-LD processor as an <abbr title="Internationalized Resource Identifier">IRI</abbr>.
+ </p>
+ <p>Consider the following example:</p>
+ <div class="example"><div class="example-title"><span>Example 21</span>: Compact IRIs</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"dc": "http://purl.org/dc/elements/1.1/",</span>
+ <span class="diff">"ex": "http://example.org/vocab#"</span>
+ },
+ "@id": "http://example.org/library",
+ "@type": <span class="diff">"ex:Library"</span>,
+ <span class="diff">"ex:contains"</span>:
+ {
+ "@id": "http://example.org/library/the-republic",
+ "@type": <span class="diff">"ex:Book"</span>,
+ <span class="diff">"dc:creator"</span>: "Plato",
+ <span class="diff">"dc:title"</span>: "The Republic",
+ <span class="diff">"ex:contains"</span>:
+ {
+ "@id": "http://example.org/library/the-republic#introduction",
+ "@type": <span class="diff">"ex:Chapter"</span>,
+ <span class="diff">"dc:description"</span>: "An introductory chapter on The Republic.",
+ <span class="diff">"dc:title"</span>: "The Introduction"
+ }
+ }
+}</pre></div>
+ <p>
+ In this example, two different <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a>
+ are referred to using prefixes. Those prefixes are then used as type and
+ property values using the compact <abbr title="Internationalized Resource Identifier">IRI</abbr> <code>prefix:suffix</code> notation.
+ </p>
+ <p>It's also possible to use compact IRIs within the context as shown in the
+ following example:</p>
+ <div class="example"><div class="example-title"><span>Example 22</span>: Using vocabularies</div><pre class="example">{
+ "@context":
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ <span class="diff">"foaf:homepage"</span>: { "@type": "@id" },
+ "picture": { "@id": <span class="diff">"foaf:depiction"</span>, "@type": "@id" }
+ },
+ "@id": "http://me.markus-lanthaler.com/",
+ "@type": "foaf:Person",
+ "foaf:name": "Markus Lanthaler",
+ "foaf:homepage": "http://www.markus-lanthaler.com/",
+ "picture": "http://twitter.com/account/profile_image/markuslanthaler"
+}</pre></div>
+</section>
+
+<section id="typed-values">
+<h3><span class="secno">4.2 </span>Typed Values</h3>
+
+<p>
+ A value with an associated type, also known as a
+ <dfn title="typed_value" id="dfn-typed_value">typed value</dfn>, is indicated by associating a value with
+ an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> which indicates the value's type. Typed values may be
+ expressed in JSON-LD in three ways:
+</p>
+
+<ol>
+ <li>By utilizing the <code>@type</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> when defining
+ a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> within a <code>@context</code> section.</li>
+ <li>By utilizing the expanded form for specifying values.</li>
+ <li>By using a native JSON type such as <a class="tref internalDFN" title="number" href="#dfn-number">number</a>, <a class="tref internalDFN" title="true" href="#dfn-true">true</a>, or <a class="tref internalDFN" title="false" href="#dfn-false">false</a>.</li>
+</ol>
+
+<p>The first example uses the <code>@type</code> keyword to associate a
+type with a particular <a class="tref internalDFN" title="term" href="#dfn-term">term</a> in the <code>@context</code>:</p>
+
+<div class="example"><div class="example-title"><span>Example 23</span>: Expanded term definition with type coercion</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "modified":
+ {
+ "@id": "http://purl.org/dc/terms/modified",
+ "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
+ }
+ },</span>
+...
+ "modified": "2010-05-29T14:17:39+02:00",
+...
+}</pre></div>
+
+<p>The <em>modified</em> key's value above is automatically type coerced to a
+datetime value because of the information specified in the
+<code>@context</code>.</p>
+
+<p>The second example uses the expanded form of setting the type information
+in the body of a JSON-LD document:</p>
+
+<div class="example"><div class="example-title"><span>Example 24</span>: Expanded value with type</div><pre class="example">{
+ "@context":
+ {
+ "modified":
+ {
+ "@id": "http://purl.org/dc/terms/modified"
+ }
+ },
+...
+ "modified":
+ <span class="diff">{
+ "@value": "2010-05-29T14:17:39+02:00",
+ "@type": "http://www.w3.org/2001/XMLSchema#dateTime"
+ }</span>
+...
+}</pre></div>
+
+<p>Both examples above would generate the value
+ <code>2010-05-29T14:17:39+02:00</code> with the type
+ <code>http://www.w3.org/2001/XMLSchema#dateTime</code>. Note that it is
+ also possible to use a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> or a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> to
+ express the value of a type.</p>
+
+<p>The <code>@type</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> is also used to associate a type
+ with a <a class="tref internalDFN" title="node" href="#dfn-node">node</a>. The concept of an <dfn title="node_type" id="dfn-node_type">node type</dfn> and
+ a <dfn title="value_type" id="dfn-value_type">value type</dfn> are different. This is similar to object-oriented
+ programming languages where both scalar and structured types use the same
+ class inheritance mechanism, even though scalar types and structured types are
+ inherently different.</p>
+
+<div class="example"><div class="example-title"><span>Example 25</span>: Example demonstrating the context-sensitivity for @type</div><pre class="example">{
+...
+ "@id": "http://example.org/posts#TripToWestVirginia",
+ <span class="diff">"@type": "http://schema.org/BlogPosting"</span>,
+ "modified":
+ {
+ "@value": "2010-05-29T14:17:39+02:00",
+ <span class="diff">"@type": "http://www.w3.org/2001/XMLSchema#dateTime"</span>
+ }
+...
+}</pre></div>
+
+<p>The first use of <code>@type</code> associates a <a class="tref internalDFN" title="node_type" href="#dfn-node_type">node type</a>
+ (<code>http://schema.org/BlogPosting</code>) with the <a class="tref internalDFN" title="node" href="#dfn-node">node</a>,
+ which is expressed using the <code>@id</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>.
+ The second use of <code>@type</code> associates a <a class="tref internalDFN" title="value_type" href="#dfn-value_type">value type</a>
+ (<code>http://www.w3.org/2001/XMLSchema#dateTime</code>) with the
+ value expressed using the <code>@value</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. As a
+ general rule, when <code>@value</code> and <code>@type</code> are used in
+ the same <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>, the <code>@type</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> is expressing a <a class="tref internalDFN" title="value_type" href="#dfn-value_type">value type</a>.
+ Otherwise, the <code>@type</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> is expressing a
+ <a class="tref internalDFN" title="node_type" href="#dfn-node_type">node type</a>.</p>
+
+</section>
+
+<section id="language-tagged-strings">
+<h3><span class="secno">4.3 </span>Language-tagged Strings</h3>
+
+<p>
+ A string with an associated language, also known as a
+ <dfn title="language-tagged_string" id="dfn-language-tagged_string">language-tagged string</dfn>, is indicated by associating a string with
+ an language code as defined in [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>]. Language-tagged strings may be
+ expressed in JSON-LD in four ways:
+</p>
+
+<ol>
+ <li>By defining a global language using the <code>@language</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> within a <code>@context</code> section.</li>
+ <li>By utilizing the <code>@language</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> when defining
+ a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> within a <code>@context</code> section.</li>
+ <li>By utilizing the expanded form for specifying values.</li>
+ <li>By utilizing the <code>@container</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> with a
+ value of <code>@language</code> when defining a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> within
+ a <code>@context</code> section. This usage pattern is called a
+ <dfn title="language_map" id="dfn-language_map">language map</dfn>.</li>
+</ol>
+
+<p>The first example uses the <code>@language</code> keyword to associate a
+type with a particular <a class="tref internalDFN" title="term" href="#dfn-term">term</a> in the <code>@context</code>:</p>
+
+<div class="example"><div class="example-title"><span>Example 26</span>: Expanded term definition with language coercion</div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title",
+ "@language": "en"
+ }
+ },</span>
+...
+ "title": "JSON-LD Syntax",
+...
+}</pre></div>
+
+<p>The <em>modified</em> key's value above is automatically
+ language coerced to a English value because of the information specified in
+ the <code>@context</code>.</p>
+
+<p>The second example uses the expanded form of setting the language information
+in the body of a JSON-LD document:</p>
+
+<div class="example"><div class="example-title"><span>Example 27</span>: Expanded value with language</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "@value": "JSON-LD Syntax",
+ "@language": "en"
+ }</span>
+...
+}</pre></div>
+
+<p>Both examples above would generate the value <code>JSON-LD Syntax</code>
+ tagged with the language <code>en</code>; which is the [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] code
+ for the English language.</p>
+
+<p>Systems that support multiple languages often need to express data values in
+each language. Typically, such systems also try to ensure that developers have
+a programatically easy way to navigate the datastructures for the
+language-specific data. In this case, <a class="tref internalDFN" title="language_map" href="#dfn-language_map">language map</a>s
+may be utilized.</p>
+
+<div class="example"><div class="example-title"><span>Example 28</span>: Language map expressing a property in three languages</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ "@container": "@language"
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "en": "JSON-LD Syntax",
+ "ru": "JSON-LD Синтаксис",
+ "ja": "JSON-LDの構文"
+ }</span>
+...
+}</pre></div>
+
+<p>In the example above, the title is expressed in three languages; English,
+ Russian, and Japanese. To access the data above in a programming language
+ supporting dot-notation accessors for object properties, a developer may
+ use the <code>property.language</code> pattern. For example, to access the
+ Japanese version of the title, a developer would use the following code
+ snippet: <code>obj.title.ja</code>.</p>
+</section>
+
+<section id="referencing-contexts-from-json-documents">
+<h3><span class="secno">4.4 </span>Referencing Contexts from JSON Documents</h3>
+
+<p>Ordinary JSON documents can be transformed into JSON-LD documents by referencing
+to an external JSON-LD <a class="tref internalDFN" title="context" href="#dfn-context">context</a> in an HTTP Link Header. Doing this
+allows JSON to be unambiguously machine-readable without requiring developers to
+drastically change their workflow and provides an upgrade path for existing
+infrastructure without breaking existing clients that rely on the <code>application/json</code>
+media type.
+</p>
+
+<p>
+In order to use an external context with an ordinary JSON document, an author
+<em class="rfc2119" title="must">must</em> specify an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> to a valid JSON-LD document in an HTTP Link
+Header [<cite><a class="bibref" href="#bib-RFC5988">RFC5988</a></cite>] using the <code>describedby</code> link relation.
+
+The referenced document <em class="rfc2119" title="must">must</em> have a top-level <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>. The
+<code>@context</code> subtree within that object is added to the top-level
+<a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> of the referencing document. If an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> is at the top-level of the
+referencing document and its items are <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a>, the <code>@context</code>
+subtree is added to all <a class="tref internalDFN" title="array" href="#dfn-array">array</a> items. All extra information located outside
+of the <code>@context</code> subtree in the referenced document <em class="rfc2119" title="must">must</em> be
+discarded.
+</p>
+
+<p>The following example demonstrates the use of an external context with an
+ordinary JSON document:</p>
+
+<div class="example"><div class="example-title"><span>Example 29</span>: Specifing context through HTTP header</div><pre class="example">GET /ordinary-json-document.json HTTP/1.1
+Host: example.com
+Accept: application/ld+json,application/json,*/*;q=0.1
+
+====================================
+
+HTTP/1.0 200 OK
+...
+Content-Type: <span class="diff">application/json</span>
+<span class="diff">Link: <http://json-ld.org/contexts/person.jsonld>; rel="describedby"; type="application/ld+json"</span>
+
+{
+ "name": "Markus Lanthaler",
+ "homepage": "http://www.markus-lanthaler.com/",
+ "depiction": "http://twitter.com/account/profile_image/markuslanthaler"
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">JSON-LD documents served with the <code>application/ld+json</code> media type
+ <em class="rfc2119" title="must">must</em> have all context information, including references to external contexts, within the
+ body of the document.</p></div>
+</section>
+
+<section id="expanded-term-definition">
+<h3><span class="secno">4.5 </span>Expanded Term Definition</h3>
+
+<p>Within a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition, <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s <em class="rfc2119" title="may">may</em> be
+ defined using an expanded notation to allow for additional information
+ associated with the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> to be specified (see also
+ <a href="#type-coercion" class="sec-ref"><span class="secno">4.6</span> <span class="sec-title">Type Coercion</span></a> and
+ <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>).</p>
+
+<p>Instead of using a string representation of an <abbr title="Internationalized Resource Identifier">IRI</abbr>, the <abbr title="Internationalized Resource Identifier">IRI</abbr> <em class="rfc2119" title="may">may</em> be
+specified using a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> having an <code>@id</code> key.
+The value of the <code>@id</code> key <em class="rfc2119" title="must">must</em> be either a <a class="tref internalDFN" title="term" href="#dfn-term">term</a>, a
+<a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>. Such
+an object is called a <a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>.</p>
+
+<div class="example"><div class="example-title"><span>Example 30</span>: Expanded term definition</div><pre class="example">{
+ "@context":
+ {
+ "foaf": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/" }</span>,
+ "name": <span class="diff">{ "@id": "http://xmlns.com/foaf/0.1/name" }</span>,
+ "homepage": <span class="diff">{ "@id": "foaf:homepage" }</span>,
+ "depiction": <span class="diff">{ "@id": "foaf:depiction" }</span>
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>This allows additional information to be associated with the term. This
+ <em class="rfc2119" title="may">may</em> be used for <a href="#type-coercion" class="sec-ref"><span class="secno">4.6</span> <span class="sec-title">Type Coercion</span></a>,
+ <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>), or to associate language
+ information with a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> as shown in the following example:</p>
+
+<div class="example"><div class="example-title"><span>Example 31</span>: Expanded term definition with language</div><pre class="example">{
+ "@context": {
+ ...
+ "ex": "http://example.com/",
+ "@language": "ja",
+ "name": { "@id": "ex:name", <span class="diff">"@language": null</span> },
+ "occupation": { "@id": "ex:occupation" },
+ "occupation_en": { "@id": "ex:occupation", <span class="diff">"@language": "en"</span> },
+ "occupation_cs": { "@id": "ex:occupation", <span class="diff">"@language": "cs"</span> }
+ },
+ <span class="diff">"name": "Yagyū Muneyoshi",
+ "occupation": "忍者",
+ "occupation_en": "Ninja",
+ "occupation_cs": "Nindža",</span>
+ ...
+}</pre></div>
+
+<p>The example above would associate <em>忍者</em> with the specified default
+ language code <code>ja</code>, <em>Ninja</em> with the language code
+ <code>en</code>, and <em>Nindža</em> with the language code <code>cs</code>.
+ The value of <code>name</code>, <em>Yagyū Muneyoshi</em> wouldn't be
+ associated with any language code since <code>@language</code> was reset to
+ <a class="tref internalDFN" title="null" href="#dfn-null">null</a> in the expanded term definition.</p>
+
+<p>Expanded terms <em class="rfc2119" title="may">may</em> also be defined using <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact IRIs</a> or
+ <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute IRIs</a> as keys. If the definition does not include an
+ <code>@id</code> key, the expanded <abbr title="Internationalized Resource Identifier">IRI</abbr> is determined by performing expansion of the key
+ within the current active context. This mechanism is mainly used to associate type or language
+ information with a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> or an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">While it is possible to define a
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or an absolute <abbr title="Internationalized Resource Identifier">IRI</abbr> to expand to some
+ other unrelated <abbr title="Internationalized Resource Identifier">IRI</abbr> (for example, <code>foaf:name</code> expanding to
+ <code>http://example.org/unrelated#species</code>),
+ such usage is strongly discouraged.</p></div>
+</section>
+
+<section id="type-coercion">
+<h3><span class="secno">4.6 </span>Type Coercion</h3>
+
+<p>JSON-LD supports the coercion of values to particular data types.
+Type <dfn title="coercion" id="dfn-coercion">coercion</dfn> allows someone deploying JSON-LD to coerce the incoming or
+outgoing values to the proper data type based on a mapping of data type <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s to
+<a class="tref internalDFN" title="term" href="#dfn-term">term</a>s. Using type coercion, value representation is preserved without requiring
+the data type to be specified with each piece of data.</p>
+
+<p>Type coercion is specified within an <a href="#expanded-term-definition" class="sec-ref"><span class="secno">4.5</span> <span class="sec-title">Expanded Term Definition</span></a>
+ using the <code>@type</code> key. The value of this key represents a type <abbr title="Internationalized Resource Identifier">IRI</abbr> and <em class="rfc2119" title="must">must</em> take the form of
+ a <a class="tref internalDFN" title="term" href="#dfn-term">term</a>, <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or the <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> <code>@id</code>. Specifying
+ <code>@id</code> indicates that within the body of a JSON-LD document, a string value of a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> coerced to
+ <code>@id</code> is to be interpreted as an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</p>
+
+<p><a class="tref internalDFN" title="term" href="#dfn-term">Terms</a> or <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact IRIs</a> used as the value of a
+ <code>@type</code> key <em class="rfc2119" title="may">may</em> be defined within the same context. This means that one may specify a
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a> like <code>xsd</code> and then use <code>xsd:integer</code> within the same
+ context definition - the JSON-LD processor will be able to determine the proper expansion for
+ <code>xsd:integer</code>.</p>
+
+<p>The example below demonstrates how a JSON-LD author can coerce values to
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>s, IRIs and lists.</p>
+
+<div class="example"><div class="example-title"><span>Example 32</span>: Expanded term definition with types</div><pre class="example">{
+ "@context":
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age":
+ <span class="diff">{
+ "@id": "http://xmlns.com/foaf/0.1/age",
+ "@type": "xsd:integer"
+ }</span>,
+ "homepage":
+ <span class="diff">{
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id",
+ "@container": "@list"
+ }</span>
+ },
+ "name": "John Smith",
+ "age": <span class="diff">"41"</span>,
+ "homepage":
+ <span class="diff">[
+ "http://personal.example.org/",
+ "http://work.example.com/jsmith/"
+ ]</span>
+}</pre></div>
+
+<p>The example above would generate the following Turtle:</p>
+
+<div class="example"><div class="example-title"><span>Example 33</span></div><pre class="example">@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+[ foaf:name "John Smith";
+ foaf:age "41"^^xsd:integer;
+ foaf:homepage ( <http://personal.example.org/> <http://work.example.com/jsmith/> )
+] .</pre></div>
+
+<p>Terms may also be defined using <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute IRIs</a> or <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact IRIs</a>.
+ This allows coercion rules to be applied to keys which are not represented as a simple <a class="tref internalDFN" title="term" href="#dfn-term">term</a>.
+ For example:</p>
+
+<div class="example"><div class="example-title"><span>Example 34</span>: Term definition with absolute IRI</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "<span class="diff">foaf:age</span>":
+ {
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">foaf:homepage</span>":
+ <span class="diff">{
+ "@type": "@id"
+ }</span>
+ },
+ "foaf:name": "John Smith",
+ "foaf:age": <span class="diff">"41"</span>,
+ "foaf:homepage":
+ <span class="diff">[
+ "http://personal.example.org/",
+ "http://work.example.com/jsmith/"
+ ]</span>
+}</pre></div>
+
+<p>In this case the <code>@id</code> definition is optional, but if it does exist, the <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ or <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is treated as a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> (not a <code>prefix:suffix</code> construct)
+ so that the actual definition of a <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> becomes unnecessary.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">Keys in the context are treated as <a class="tref internalDFN" title="term" href="#dfn-term">terms</a> for the purpose of
+ expansion and value coercion. At times, this may result in multiple representations for the same expanded <abbr title="Internationalized Resource Identifier">IRI</abbr>.
+ For example, one could specify that <code>dog</code> and <code>cat</code> both expanded to <code>http://example.com/vocab#animal</code>.
+ Doing this could be useful for establishing different type coercion or language specification rules. It also allows a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> (or even an
+ absolute <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>) to be defined as something else entirely. For example, one could specify that
+ the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> <code>http://example.org/zoo</code> should expand to
+ <code>http://example.org/river</code>, but this usage is discouraged because it would lead to a
+ great deal of confusion among developers attempting to understand the JSON-LD document.</p></div>
+
+<p>Type coercion is performed using the unexpanded value of the key,
+ which <em class="rfc2119" title="must">must</em> have an exact match for an entry in the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>.</p>
+
+</section>
+
+
+<section id="property-generators">
+<h3><span class="secno">4.7 </span>Property Generators</h3>
+
+<p>At times, an author may find that they need to express the same value for
+multiple properties. The simplest approach to accomplish this goal would be
+to do the following:</p>
+
+<div class="example"><div class="example-title"><span>Example 35</span>: Verbose expression of multiple properties with the same value</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"title1": "http://purl.org/dc/terms/title"</span>,
+ <span class="diff">"title2": "http://schema.org/name"</span>,
+ <span class="diff">"title3": "http://www.w3.org/2000/01/rdf-schema#label"</span>
+ },
+ "@id": "http://example.com/book",
+ <span class="diff">"title1": "The Count of Monte Cristo"</span>,
+ <span class="diff">"title2": "The Count of Monte Cristo"</span>,
+ <span class="diff">"title3": "The Count of Monte Cristo"</span>
+}</pre></div>
+
+<p>Unfortunately, the approach above produces redundant data and would become a
+publishing burden for large data sets.
+In these situations, the author may use
+a <dfn title="property_generator" id="dfn-property_generator">property generator</dfn> to express a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> once, but have
+the JSON-LD processor expand the single statement into multiple statements.
+This method can be accomplished by using the following markup pattern:</p>
+
+<div class="example"><div class="example-title"><span>Example 36</span>: Generating multiple properties using a single term</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"title": { "@id": [ "http://purl.org/dc/terms/title",
+ "http://schema.org/name",
+ "http://www.w3.org/2000/01/rdf-schema#label" ] }</span>
+ },
+ "@id": "http://example.com/book",
+ <span class="diff">"title": "The Count of Monte Cristo"</span>
+}</pre></div>
+
+<p>While the term above is only used once outside of the <code>@context</code>,
+a JSON-LD processor will internally transform the document above into
+the following set of statements:</p>
+
+<div class="example"><div class="example-title"><span>Example 37</span></div><pre class="example"><http://example.com/book>
+ <http://purl.org/dc/terms/title>
+ "The Count of Monte Cristo" .
+<http://example.com/book>
+ <http://schema.org/name>
+ "The Count of Monte Cristo" .
+<http://example.com/book>
+ <http://www.w3.org/2000/01/rdf-schema#label>
+ "The Count of Monte Cristo" .</pre></div>
+
+</section>
+
+<section id="iri-expansion-within-a-context">
+ <h3><span class="secno">4.8 </span><abbr title="Internationalized Resource Identifier">IRI</abbr> Expansion Within a Context</h3>
+ <p>In general, normal <abbr title="Internationalized Resource Identifier">IRI</abbr> expansion rules apply
+ anywhere an <abbr title="Internationalized Resource Identifier">IRI</abbr> is expected (see <a href="#iris" class="sec-ref"><span class="secno">3.7</span> <span class="sec-title">IRIs</span></a>). Within
+ a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition, this can mean that terms defined
+ within the context <em class="rfc2119" title="may">may</em> also be used within that context as long as
+ there are no circular dependencies. For example, it is common to use
+ the <code>xsd</code> namespace when defining <a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>s:</p>
+<div class="example"><div class="example-title"><span>Example 38</span>: IRI expansion within context</div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"xsd": "http://www.w3.org/2001/XMLSchema#"</span>,
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/age",
+ "@type": <span class="diff">"xsd:integer"</span>
+ },
+ "homepage":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ ...
+}</pre></div>
+<p>In this example, the <code>xsd</code> <a class="tref internalDFN" title="term" href="#dfn-term">term</a> is defined
+ and used as a <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> for the <code>@type</code> coercion
+ of the <code>age</code> property.</p>
+
+<p><a class="tref internalDFN" title="term" href="#dfn-term">Term</a>s <em class="rfc2119" title="may">may</em> also be used when defining the <abbr title="Internationalized Resource Identifier">IRI</abbr> of another
+<a class="tref internalDFN" title="term" href="#dfn-term">term</a>:</p>
+
+<div class="example"><div class="example-title"><span>Example 39</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": <span class="diff">"foaf:name"</span>,
+ "age":
+ {
+ "@id": <span class="diff">"foaf:age"</span>,
+ "@type": "xsd:integer"
+ },
+ "homepage":
+ {
+ "@id": <span class="diff">"foaf:homepage"</span>,
+ "@type": "@id"
+ }
+ },
+ ...
+}</pre></div>
+
+<p><a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">Compact IRIs</a>
+ and <a class="tref internalDFN" title="iri" href="#dfn-iri">IRIs</a> <em class="rfc2119" title="may">may</em> be used on the left-hand side of a
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a> definition.</p>
+
+<div class="example"><div class="example-title"><span>Example 40</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"foaf": "http://xmlns.com/foaf/0.1/"</span>,
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "foaf:name",
+ "<span class="diff">foaf:age</span>":
+ {
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">foaf:homepage</span>":
+ <span class="diff">{
+ "@type": "@id"
+ }</span>
+ },
+ ...
+}</pre></div>
+
+<p>
+In this example, the <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> form is used in two different
+ways.
+In the first approach, <code>foaf:age</code> declares both the
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> for the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> (using short-form) as well as the
+<code>@type</code> associated with the <a class="tref internalDFN" title="term" href="#dfn-term">term</a>. In the second
+approach, only the <code>@type</code> associated with the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> is
+specified. The JSON-LD processor will derive the full <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> for
+<code>foaf:homepage</code> by looking up the <code>foaf</code>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> in the
+<a class="tref internalDFN" title="context" href="#dfn-context">context</a>.
+</p>
+
+<p>
+<a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">Absolute IRIs</a> <em class="rfc2119" title="may">may</em> also be used in the key position in a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>:
+</p>
+
+<div class="example"><div class="example-title"><span>Example 41</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "foaf:name",
+ "foaf:age":
+ {
+ "@id": "foaf:age",
+ "@type": "xsd:integer"
+ },
+ "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>":
+ {
+ "@type": "@id"
+ }
+ },
+ ...
+}</pre></div>
+
+<p>
+In order for the <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> to match above, the <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> <em class="rfc2119" title="must">must</em> also
+be used in the JSON-LD document. Also note that <code>foaf:homepage</code>
+will not use the <code>{ "@type": "@id" }</code> declaration because
+<code>foaf:homepage</code> is not the same as
+<code>http://xmlns.com/foaf/0.1/homepage</code>. That is, a JSON-LD
+processor will use direct string comparison when looking up
+<a class="tref internalDFN" title="term" href="#dfn-term">term</a>s in a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> before it applies the
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> lookup mechanism.
+</p>
+
+<p>The only exception for using terms in the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> is that
+ they <em class="rfc2119" title="must not">must not</em> be used in a circular manner. That is,
+ a definition of <em>term-1</em> <em class="rfc2119" title="must not">must not</em> depend on the
+ definition of <em>term-2</em> if <em>term-2</em> also depends on
+ <em>term-1</em>. For example, the following <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition
+ is illegal:</p>
+<div class="example"><div class="example-title"><span>Example 42</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"term1": "term2:foo",
+ "term2": "term1:bar"</span>
+ },
+ ...
+}</pre></div>
+</section>
+
+<section id="sets-and-lists">
+<h3><span class="secno">4.9 </span>Sets and Lists</h3>
+
+<p>A JSON-LD author can express multiple values in a compact way by using
+ <a class="tref internalDFN" title="array" href="#dfn-array">array</a>s. Since graphs do not describe ordering for links
+ between nodes, arrays in JSON-LD do not provide an ordering of the
+ contained elements by default. This is exactly the opposite from regular JSON
+ arrays, which are ordered by default. For example, consider the following
+ simple document:</p>
+
+<div class="example"><div class="example-title"><span>Example 43</span></div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}</pre></div>
+
+<p>The markup shown above would result in three triples being generated,
+ each relating the node to an individual value, with no inherent order:</p>
+
+<div class="issue"><div class="issue-title"><span>Issue</span></div><p class="">Including an illustration might be better.</p></div>
+
+<div class="example"><div class="example-title"><span>Example 44</span></div><pre class="example"><http://example.org/people#joebob> <http://xmlns.com/foaf/0.1/nick> "joe" .
+<http://example.org/people#joebob> <http://xmlns.com/foaf/0.1/nick> "bob" .
+<http://example.org/people#joebob> <http://xmlns.com/foaf/0.1/nick> "jaybee" .</pre></div>
+
+<p>Multiple values may also be expressed using the expanded form:</p>
+
+<div class="example"><div class="example-title"><span>Example 45</span></div><pre class="example">{
+ "@id": "http://example.org/articles/8",
+ "dc:title": <span class="diff">
+ [
+ {
+ "@value": "Das Kapital",
+ "@language": "de"
+ },
+ {
+ "@value": "Capital",
+ "@language": "en"
+ }
+ ]</span>
+}</pre></div>
+
+<p>The markup shown above would generate the following triples, again with
+ no inherent order:</p>
+
+<div class="issue"><div class="issue-title"><span>Issue</span></div><p class="">Including an illustration might be better.</p></div>
+
+<div class="example"><div class="example-title"><span>Example 46</span></div><pre class="example"><http://example.org/articles/8> <http://purl.org/dc/terms/title> "Das Kapital"@de .
+<http://example.org/articles/8> <http://purl.org/dc/terms/title> "Capital"@en .</pre></div>
+
+
+<p>As the notion of ordered collections is rather important in data
+ modeling, it is useful to have specific language support. In JSON-LD,
+ a list may be represented using the <code>@list</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> as follows:</p>
+<div class="example"><div class="example-title"><span>Example 47</span></div><pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "foaf:nick":
+ <span class="diff">{
+ "@list": [ "joe", "bob", "jaybee" ]
+ }</span>,
+...
+}</pre></div>
+
+<p>This describes the use of this <a class="tref internalDFN" title="array" href="#dfn-array">array</a> as being ordered,
+ and order is maintained when processing a document. If every use of a given multi-valued
+ property is a list, this may be abbreviated by setting <code>@container</code>
+ to <code>@list</code> in the <a class="tref internalDFN" title="context" href="#dfn-context">context</a>:</p>
+<div class="example"><div class="example-title"><span>Example 48</span></div><pre class="example">{
+ <span class="diff">"@context":
+ {
+ ...
+ "nick":
+ {
+ "@id": "http://xmlns.com/foaf/0.1/nick",
+ "@container": "@list"
+ }
+ }</span>,
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">List of lists are not allowed in this version of JSON-LD.
+ If a list of lists is detected, a JSON-LD processor will throw an exception.
+ This decision was made due to the extreme amount of added complexity when
+ processing lists of lists.</p></div>
+
+<p>Similarly to <code>@list</code>, there exists the <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> <code>@set</code> to
+ describe unordered sets. While its use in the body of a JSON-LD document
+ represents just syntactic sugar that <em class="rfc2119" title="must">must</em> be optimized away when processing
+ the document, it is very helpful when used within the context of a document.
+ Values of terms associated with a <code>@set</code> or <code>@list</code> container
+ are always represented in the form of an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> - even if there is just a
+ single value that would otherwise be optimized to a non-array form in a
+ <a href="#compact-document-form" class="sec-ref"><span class="secno">4.15</span> <span class="sec-title">Compact Document Form</span></a>. This makes post-processing of
+ the data easier as the data is always in array form, even if the array only
+ contains a single value.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">The use of <code>@container</code> in the body of a JSON-LD
+ document, i.e., outside <code>@context</code> <em class="rfc2119" title="must">must</em> be ignored by
+ JSON-LD processors.</p></div>
+
+</section>
+
+<section id="embedding">
+ <h3><span class="secno">4.10 </span>Embedding</h3>
+
+ <p><dfn title="embedding" id="dfn-embedding">Embedding</dfn> is a JSON-LD feature that allows an author to
+ use <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a> as
+ <a class="tref internalDFN" title="property" href="#dfn-property">property</a> values. This is a commonly used mechanism for
+ creating a parent-child relationship between two <a class="tref internalDFN" title="node" href="#dfn-node">node</a>s.</p>
+
+ <p>The example shows two nodes related by a property from the first node:</p>
+
+ <div class="example"><div class="example-title"><span>Example 49</span></div><pre class="example">{
+...
+ "name": "Manu Sporny",
+ "<span class="diff">knows</span>":
+ {
+ "<span class="diff">@type</span>": "<span class="diff">Person</span>",
+ "<span class="diff">name</span>": "<span class="diff">Gregg Kellogg</span>",
+ }
+...
+}</pre></div>
+
+ <p>
+ A <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>, like the one used above, <em class="rfc2119" title="may">may</em> be used in
+ any value position in the body of a JSON-LD document.</p>
+</section>
+
+<section id="named-graphs">
+ <h3><span class="secno">4.11 </span>Named Graphs</h3>
+ <p>The <code>@graph</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> is used to express a set of
+ JSON-LD <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>s that may not be directly related
+ to one another through a property. The mechanism may also be used where
+ <a class="tref internalDFN" title="embedding" href="#dfn-embedding">embedding</a> is not desirable to the application. For example:</p>
+
+ <div class="example"><div class="example-title"><span>Example 50</span></div><pre class="example">{
+ "@context": ...,
+ "<span class="diff">@graph</span>":
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}</pre></div>
+
+ <p>In this case, embedding doesn't work as each
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> references the other. Using the
+ <code>@graph</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> allows multiple resources to be
+ defined within an <a class="tref internalDFN" title="array" href="#dfn-array">array</a>, and allows the use of a shared
+ <a class="tref internalDFN" title="context" href="#dfn-context">context</a>. When used in a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> that is not otherwise
+ a <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>, this describes resources in the <em>default graph</em>.
+ This is equivalent to using multiple <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a> in array and defining
+ the <code>@context</code> within each <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>:</p>
+
+ <div class="example"><div class="example-title"><span>Example 51</span></div><pre class="example"><span class="diff">[</span>
+ {
+ <span class="diff">"@context": ...,</span>
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ <span class="diff">"@context": ...,</span>
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+<span class="diff">]</span></pre></div>
+
+ <p>JSON-LD allows you to <em>name</em> things on the Web by assigning
+ an <code>@id</code> to them, which is typically an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.
+ This notion extends to the ability to identify graphs in the same
+ manner. A developer may name data expressed using the <code>@graph</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> by pairing it with an <code>@id</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. This enables the developer to make statements
+ about a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> itself,
+ rather than just a single <a class="tref internalDFN" title="node" href="#dfn-node">node</a>.</p>
+
+ <div class="example"><div class="example-title"><span>Example 52</span></div><pre class="example">{
+ "@context": ...,
+ <span class="diff">"@id": "http://example.org/graphs/73",
+ "asOf": { "@value": "2012-04-09", "@type": "xsd:date" },
+ "@graph":</span>
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}</pre></div>
+
+ <p>The example above expresses a <em>named</em>
+ <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> that is identified by the <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+ <code>http://example.org/graphs/73</code>. That graph is composed of the
+ statements about Manu and Gregg. Meta-data about the graph itself is also
+ expressed via the <code>asOf</code> property, which specifies when the
+ information was retrieved from the Web.</p>
+
+ <div class="issue"><div class="issue-title"><span>Issue</span></div><p class="">These examples could all have TriG definitions of their RDF results,
+ but that would involve adding RDF earlier in the document.</p></div>
+
+</section>
+
+<section id="identifying-unlabeled-nodes">
+<h3><span class="secno">4.12 </span>Identifying Unlabeled Nodes</h3>
+
+<p>At times, it becomes necessary to be able to express information without
+being able to specify the node. Typically, this type of node is called
+an <dfn title="unlabeled_node" id="dfn-unlabeled_node">unlabeled node</dfn> or a <dfn title="blank_node" id="dfn-blank_node">blank node</dfn> (see [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>] <cite><a href="http://www.w3.org/TR/rdf11-concepts/#section-blank-nodes">Section 3.4: Blank Nodes</a></cite>).
+In JSON-LD, <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a> identifiers are
+automatically created if a node is not specified using the
+<code>@id</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. However, authors may provide identifiers for
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled nodes</a> by using the special <code>_</code> (underscore)
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>. This allows one to reference the node locally within the
+document, but makes it impossible to reference the node from an
+external document. The <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a> identifier is scoped to the
+document in which it is used.</p>
+
+<div class="example"><div class="example-title"><span>Example 53</span></div><pre class="example">{
+...
+ "@id": "<span class="diff">_:foo</span>",
+...
+}</pre></div>
+
+<p>The example above would set the node to <code>_:foo</code>, which can
+then be used elsewhere in the JSON-LD document to refer back to the
+<a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a>. If a developer finds that they refer to the unlabeled
+node more than once, they should consider naming the node using a de-referenceable
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> so that it can be referenced also from other documents.
+</p>
+
+</section>
+
+<section id="aliasing-keywords">
+<h3><span class="secno">4.13 </span>Aliasing Keywords</h3>
+
+<p>Each of the JSON-LD <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a>,
+except for <code>@context</code>, <em class="rfc2119" title="may">may</em> be aliased to application-specific
+keywords. This feature allows legacy JSON content to be utilized
+by JSON-LD by re-using JSON keys that already exist in legacy documents.
+This feature also allows developers to design domain-specific implementations
+using only the JSON-LD <a class="tref internalDFN" title="context" href="#dfn-context">context</a>.</p>
+
+<div class="example"><div class="example-title"><span>Example 54</span></div><pre class="example">{
+ "@context":
+ {
+ <span class="diff">"url": "@id"</span>,
+ <span class="diff">"a": "@type"</span>,
+ "name": "http://schema.org/name"
+ },
+ "<span class="diff">url</span>": "http://example.com/about#gregg",
+ "<span class="diff">a</span>": "http://schema.org/Person",
+ "name": "Gregg Kellogg"
+}</pre></div>
+
+<p>In the example above, the <code>@id</code> and <code>@type</code>
+<a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a> have been given the aliases <strong>url</strong> and
+<strong>a</strong>, respectively.
+</p>
+
+</section>
+
+<section id="expanded-document-form">
+<h3><span class="secno">4.14 </span>Expanded Document Form</h3>
+<p>The JSON-LD API [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>] defines an method for <em>expanding</em> a
+ JSON-LD document.
+ Expansion is the process of taking a JSON-LD document and applying a
+ <code>@context</code> such that all IRIs, types, and values
+ are expanded so that the <code>@context</code> is no longer necessary.</p>
+
+<p>For example, assume the following JSON-LD input document:</p>
+
+<div class="example"><div class="example-title"><span>Example 55</span></div><pre class="example">{
+ "@context":
+ {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+}</pre></div>
+
+<p>Running the JSON-LD Expansion algorithm against the JSON-LD input document
+ provided above would result in the following output:</p>
+
+<div class="example"><div class="example-title"><span>Example 56</span></div><pre class="example">[
+ {
+ "http://xmlns.com/foaf/0.1/name": [
+ { "@value": "Manu Sporny" }
+ ],
+ "http://xmlns.com/foaf/0.1/homepage": [
+ { "@id": "http://manu.sporny.org/" }
+ ]
+ }
+]</pre></div>
+
+<p>Expanded document form is useful when an application has to process input
+data in a deterministic form. It has been optimized to ensure that the code
+that developers have to write is minimized compared to the code that would
+have to be written to operate on
+<a href="#compact-document-form" class="sec-ref"><span class="secno">4.15</span> <span class="sec-title">Compact Document Form</span></a>.</p>
+
+</section>
+
+<section id="compact-document-form">
+<h3><span class="secno">4.15 </span>Compact Document Form</h3>
+<p>The JSON-LD API [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>] defines a method for <em>compacting</em> a JSON-LD document.
+ Compaction is the process of taking a JSON-LD document and applying a
+ context such that the most compact form of the document is generated. JSON
+ is typically expressed in a very compact, key-value format. That is, full
+ IRIs are rarely used as keys. At times, a JSON-LD document may be received
+ that is not in its most compact form. JSON-LD, via the API, provides a way
+ to compact a JSON-LD document.</p>
+
+<p>For example, assume the following JSON-LD input document:</p>
+
+<div class="example"><div class="example-title"><span>Example 57</span></div><pre class="example">[
+ {
+ "http://xmlns.com/foaf/0.1/name": [ "Manu Sporny" ],
+ "http://xmlns.com/foaf/0.1/homepage": [
+ {
+ "@id": "http://manu.sporny.org/"
+ }
+ ]
+ }
+]</pre></div>
+
+<p>Additionally, assume the following developer-supplied JSON-LD context:</p>
+
+<div class="example"><div class="example-title"><span>Example 58</span></div><pre class="example">{
+ "@context": {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ }
+}</pre></div>
+
+<p>Running the JSON-LD Compaction algorithm given the context supplied above
+ against the JSON-LD input document provided above would result in the following
+ output:</p>
+
+<div class="example"><div class="example-title"><span>Example 59</span></div><pre class="example">{
+ "@context": {
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": {
+ "@id": "http://xmlns.com/foaf/0.1/homepage",
+ "@type": "@id"
+ }
+ },
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+}</pre></div>
+
+<p>The compaction algorithm enables a developer to map any document into an
+ application-specific compacted form by first <a href="#expanded-document-form" class="sec-ref"><span class="secno">4.14</span> <span class="sec-title">Expanded Document Form</span></a>.
+ While the context provided above mapped <code>http://xmlns.com/foaf/0.1/name</code>
+ to <strong>name</strong>, it could have also mapped it to any arbitrary string
+ provided by the developer. This powerful mechanism, along with another
+ JSON-LD API technique called <em>framing</em>, allows the developer to
+ re-shape the incoming JSON data into a format that is optimized for
+ their application.</p>
+</section>
+
+</section>
+
+<section class="appendix normative" id="json-ld-grammar">
+
+<!--OddPage-->
+<h2><span class="secno">A. </span>JSON-LD Grammar</h2>
+<em>This section is normative</em>
+
+<p class="issue resolved" data-number="114">This section is an attempt to formalize
+a normative grammar for JSON-LD.</p>
+
+<p>This appendix restates the syntactic conventions described in the
+ previous sections more formally.</p>
+
+<p>A JSON-LD processor <em class="rfc2119" title="should">should</em> attempt to process non-conforming
+ JSON-LD documents. Conformance violations <em class="rfc2119" title="must">must</em> be reported through a
+ conformance violation callback mechanism defined in the [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>].</p>
+
+<p>For a JSON-LD document to be conforming, it <em class="rfc2119" title="must">must</em> be a valid JSON document
+ as described in [<cite><a class="bibref" href="#bib-RFC4627">RFC4627</a></cite>].</p>
+
+<p>JSON-LD introduces a number of keywords of the form '<code>@</code>'
+ followed by a set of one or more lower case alphabetic characters
+ (<code>@[a-z]+</code>). JSON-LD documents <em class="rfc2119" title="should not">should not</em> define terms beginning
+ with '<code>@</code>'.
+ (See <a href="#syntax-tokens-and-keywords" class="sec-ref"><span class="secno">3.4</span> <span class="sec-title">Syntax Tokens and Keywords</span></a> for a complete definition of JSON-LD keywords).</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">The JSON-LD context allows <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a> to be
+ aliased within the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>. Whenever a <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> is
+ discussed, this is also understood to apply to an alias for that <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>
+ For example, if the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> defines the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> <code>id</code> as
+ an alias for <code>@id</code>, that alias may be legitimately used as a substitution
+ for <code>@id</code>. Note that <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> aliases are not expanded during
+ context processing.</p></div>
+
+<p>A JSON-LD document is either a
+ a single <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>
+ or a JSON <a class="tref internalDFN" title="array" href="#dfn-array">array</a> containing a set of
+ one or more <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a>.</p>
+<div class="example"><div class="example-title"><span>Example 60</span>: Simple node definition</div><pre class="example">{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+<div class="example"><div class="example-title"><span>Example 61</span>: Array of node definitions</div><pre class="example">[
+ {
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+ }, {
+ "name": "Gregg Kellogg",
+ "homepage": "http://greggkellogg.net/",
+ "depiction": "http://twitter.com/account/profile_image/gkellogg"
+ }
+]</pre></div>
+
+<section id="grammar-node-definition">
+<h3><span class="secno">A.1 </span>Node Definition</h3>
+<p>A <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> is a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>
+ containing one or more key-value pairs. Keys are <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s,
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>s,
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s defined within the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>, or one of the
+ following keywords:</p>
+<ul>
+ <li><code>@context</code>,</li>
+ <li><code>@graph</code>,</li>
+ <li><code>@id</code>, or</li>
+ <li><code>@type</code></li>
+</ul>
+<p>If the <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> contains the <code>@context</code>
+ key, its value <em class="rfc2119" title="must">must</em> be one of the following:</p>
+<ul>
+ <li>a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> with the lexical form of <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>,</li>
+ <li>a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> conforming the the syntax requirements stated
+ in <a href="#grammar-context" class="sec-ref"><span class="secno">A.6</span> <span class="sec-title">Context Definition</span></a>, or</li>
+ <li>an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> composed of any number of the previous two expressions.</li>
+</ul>
+<div class="example"><div class="example-title"><span>Example 62</span>: Node definition with external context</div><pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person.jsonld"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+<p>See <a href="#node-identifiers" class="sec-ref"><span class="secno">3.8</span> <span class="sec-title">Node Identifiers</span></a>, <a href="#compact-iris" class="sec-ref"><span class="secno">4.1</span> <span class="sec-title">Compact IRIs</span></a>,
+ and <a href="#identifying-unlabeled-nodes" class="sec-ref"><span class="secno">4.12</span> <span class="sec-title">Identifying Unlabeled Nodes</span></a> for further discussion on
+ <code>@id</code> values.</p>
+
+<p>If the <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> contains the <code>@id</code>
+ key, it's value
+ <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> having the lexical form of <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> (including <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a>), or a
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined in the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> expanding
+ into an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or an <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled node</a>.</p>
+
+<div class="example"><div class="example-title"><span>Example 63</span>: Node definition with @id</div><pre class="example">{
+ "@context": "http://json-ld.org/contexts/person.jsonld",
+ <span class="diff">"@id": "http://manu.sporny.org/i/public"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+
+<p>If the <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> contains the <code>@type</code>
+ key, it's value
+ <em class="rfc2119" title="must">must</em> be either a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> having the lexical form of
+ <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined in the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> expanding into an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ or an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> of any of these.</p>
+
+<p>A JSON-LD processor <em class="rfc2119" title="should">should</em> process non-conforming documents
+ having <code>@type</code> values including <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> or
+ <a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a> entries but <em class="rfc2119" title="must">must</em>
+ discard everything except for the value of the <code>@id</code> key.</p>
+
+<div class="example"><div class="example-title"><span>Example 64</span>: Node definition with @type</div><pre class="example">{
+ "@context": "http://json-ld.org/contexts/person.jsonld",
+ "@id": "http://manu.sporny.org/i/public",
+ <span class="diff">"@type": "Person"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre></div>
+<p>See <a href="#specifying-the-type" class="sec-ref"><span class="secno">3.9</span> <span class="sec-title">Specifying the Type</span></a> for further discussion on
+ <code>@type</code> values.</p>
+
+<p>If the <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> contains the <code>@graph</code>
+ key, it's value <em class="rfc2119" title="must">must</em>
+ be a <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> or an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> of zero or more
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a>. If the
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> contains an <code>@id</code> keyword,
+ its value is used as the label of a named graph.</p>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">As a special case, if the <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> contains no
+ keys other than <code>@graph</code> and <code>@context</code>, and the
+ <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is the root of the JSON-LD document, the
+ <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is not treated as a <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>; this
+ is used as a way of defining <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node
+ definitions</a> that may not form a connected graph. This allows a
+ <a class="tref internalDFN" title="context" href="#dfn-context">context</a> to be defined which is shared by all of the constituent
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definitions</a>.</p></div>
+
+
+<div class="example"><div class="example-title"><span>Example 65</span>: Multiple node definitions with a single context using @graph</div><pre class="example">{
+ "@context": ...,
+ "<span class="diff">@graph</span>":
+ [
+ {
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "name": "Manu Sporny",
+ "knows": "http://greggkellogg.net/foaf#me"
+ },
+ {
+ "@id": "http://greggkellogg.net/foaf#me",
+ "@type": "foaf:Person",
+ "name": "Gregg Kellogg",
+ "knows": "http://manu.sporny.org/i/public"
+ }
+ ]
+}</pre></div>
+
+<p>See <a href="#named-graphs" class="sec-ref"><span class="secno">4.11</span> <span class="sec-title">Named Graphs</span></a> for further discussion on
+ <code>@graph</code> values.</p>
+
+<p>A JSON-LD document <em class="rfc2119" title="must not">must not</em> contain any <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> or
+ alias that expands to another keyword.</p>
+
+<p>Other keys <em class="rfc2119" title="must">must</em> expand to an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> using the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>. The values associated with these keys
+ may be any of the following:</p>
+
+<ul>
+ <li><a class="tref internalDFN" title="string" href="#dfn-string">string</a>,</li>
+ <li><a class="tref internalDFN" title="number" href="#dfn-number">number</a>,</li>
+ <li><a class="tref internalDFN" title="true" href="#dfn-true">true</a>,</li>
+ <li><a class="tref internalDFN" title="false" href="#dfn-false">false</a>,</li>
+ <li><a class="tref internalDFN" title="null" href="#dfn-null">null</a>,</li>
+ <li><a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>,</li>
+ <li><a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>,</li>
+ <li><a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>,</li>
+ <li><a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">language-tagged string</a>,</li>
+ <li><code>@set</code> or <code>@list</code>
+ definition (see <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>),</li>
+ <li>an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> zero or more of these, or</li>
+ <li>a <a class="tref internalDFN" title="language_map" href="#dfn-language_map">language map</a></li>
+</ul>
+
+</section>
+
+<section id="grammar-node-reference">
+<h3><span class="secno">A.2 </span>Node Reference</h3>
+<p>A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> containing only the <code>@id</code>
+ (or an alias for <code>@id</code>) is a <a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a> and not a
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>.
+</p>
+<div class="example"><div class="example-title"><span>Example 66</span>: Explicit node reference</div><pre class="example">{
+ "@context": ...,
+ "@graph": [
+ {
+ "@id": "http://example.org/library",
+ "@type": "ex:Library",
+ <span class="diff">"ex:contains": {"@id": "http://example.org/library/the-republic"}</span>
+ }, {
+ "@id": "http://example.org/library/the-republic",
+ "@type": "ex:Book",
+ "dc:creator": "Plato",
+ "dc:title": "The Republic",
+ <span class="diff">"ex:contains": {"@id": "http://example.org/library/the-republic#introduction"}</span>
+ }, {
+ "@id": "http://example.org/library/the-republic#introduction",
+ "@type": "ex:Chapter",
+ "dc:description": "An introductory chapter on The Republic.",
+ "dc:title": "The Introduction"
+ }
+ ]
+}
+}</pre></div>
+</section>
+
+<section id="grammar-language-map">
+<h3><span class="secno">A.3 </span>Language Map</h3>
+<p>A <a class="tref internalDFN" title="language_map" href="#dfn-language_map">language map</a> may be used as a term value within a
+ <a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a> if the term is defined with
+ <code>@container</code> set to <code>@language</code>.</p>
+<p>The keys of a <a class="tref internalDFN" title="language_map" href="#dfn-language_map">language map</a> <em class="rfc2119" title="must">must</em> be a [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] string
+ with an associated value that is any of the following types:</p>
+<ul>
+ <li><a class="tref internalDFN" title="string" href="#dfn-string">string</a>,</li>
+ <li><a class="tref internalDFN" title="number" href="#dfn-number">number</a>,</li>
+ <li><a class="tref internalDFN" title="true" href="#dfn-true">true</a>,</li>
+ <li><a class="tref internalDFN" title="false" href="#dfn-false">false</a>,</li>
+ <li><a class="tref internalDFN" title="null" href="#dfn-null">null</a>,</li>
+ <li><a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>,</li>
+ <li><a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>,</li>
+ <li><a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>,</li>
+ <li><a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">language-tagged string</a>,</li>
+ <li><code>@set</code> or <code>@list</code>
+ definition (see <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>), or</li>
+ <li>an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> zero or more of these</li>
+</ul>
+<p class="issue resolved" data-number="133">We had also discussed values other than strings, such as those that might represent a more reified version of a value with other properties, such as is described using <a href="http://www.w3.org/TR/skos-reference/skos-xl.html">SKOS-XL</a>.</p>
+<div class="example"><div class="example-title"><span>Example 67</span>: Language map expressing a property in three languages</div><pre class="example">{
+ "@context":
+ {
+ "title":
+ {
+ "@id": "http://purl.org/dc/terms/title"
+ <span class="diff">"@container": "@language"</span>
+ }
+ },
+...
+ "title":
+ <span class="diff">{
+ "en": "JSON-LD Syntax",
+ "ru": "JSON-LD Синтаксис",
+ "ja": "JSON-LDの構文"
+ }</span>
+...
+}</pre></div>
+</section>
+
+<section id="grammar-expanded-values">
+<h3><span class="secno">A.4 </span>Expanded Values</h3>
+<p>An <dfn title="expanded_value" id="dfn-expanded_value">expanded value</dfn> is a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> containing the
+ <code>@value</code> key, or an alias for the <code>@value</code> value key.
+ It <em class="rfc2119" title="may">may</em>
+ also contain the <code>@type</code> or <code>@language</code> keys, or their
+ respective keyword aliases. An <a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">expanded value</a> <em class="rfc2119" title="must not">must not</em>
+ contain keys other than <code>@value</code>, <code>@language</code>, and
+ <code>@type</code>.
+ An <a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">expanded value</a> <em class="rfc2119" title="must not">must not</em> contain both the
+ <code>@language</code> and <code>@type</code> keys.</p>
+ <p>The value of the <code>@value</code> key, or its alias, <em class="rfc2119" title="must">must</em> be either a
+ <a class="tref internalDFN" title="string" href="#dfn-string">string</a>, <a class="tref internalDFN" title="number" href="#dfn-number">number</a>, <a class="tref internalDFN" title="true" href="#dfn-true">true</a>, or
+ <a class="tref internalDFN" title="false" href="#dfn-false">false</a>.</p>
+<p>If an <a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">expanded value</a> contains a <code>@language</code> key,
+ it <em class="rfc2119" title="must not">must not</em> contain any other key except <code>@value</code>. The value of
+ the <code>@language</code> key <em class="rfc2119" title="must">must</em> have the lexical form described in
+ [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>], or be <a class="tref internalDFN" title="null" href="#dfn-null">null</a>.</p>
+<p>If an <a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">expanded value</a> contains a <code>@type</code> key, it
+ <em class="rfc2119" title="must not">must not</em> contain any other key except <code>@value</code>. The value of
+ <code>@type</code> <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="term" href="#dfn-term">term</a>, <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or <code>null</code>.</p>
+<p>See <a href="#typed-values" class="sec-ref"><span class="secno">4.2</span> <span class="sec-title">Typed Values</span></a> and <a href="#language-tagged-strings" class="sec-ref"><span class="secno">4.3</span> <span class="sec-title">Language-tagged Strings</span></a>
+ for a further discussion of
+ <a class="tref internalDFN" title="expanded_value" href="#dfn-expanded_value">expanded values</a>.</p>
+</section>
+
+<section id="grammar-set-list">
+<h3><span class="secno">A.5 </span>List and Set Values</h3>
+
+<p>A <dfn title="list" id="dfn-list">list</dfn> is a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> having only the <code>@list</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. Its value <em class="rfc2119" title="must">must</em> be an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> of any of the following:</p>
+<ul>
+ <li><a class="tref internalDFN" title="string" href="#dfn-string">string</a>,</li>
+ <li><a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>,</li>
+ <li><a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>,</li>
+ <li><a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>, or</li>
+ <li><a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">language-tagged string</a>.</li>
+</ul>
+<p>A <dfn title="set" id="dfn-set">set</dfn> is a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> having only the <code>@set</code>
+ <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>. Its value <em class="rfc2119" title="must">must</em> be an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> of any of the following:</p>
+<ul>
+ <li><a class="tref internalDFN" title="string" href="#dfn-string">string</a>,</li>
+ <li><a class="tref internalDFN" title="node_reference" href="#dfn-node_reference">node reference</a>,</li>
+ <li><a class="tref internalDFN" title="node_definition" href="#dfn-node_definition">node definition</a>,</li>
+ <li><a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>,</li>
+ <li><a class="tref internalDFN" title="language-tagged_string" href="#dfn-language-tagged_string">language-tagged string</a>,</li>
+ <li><code>@set</code> or <code>@list</code>
+ definition (see <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a>), or</li>
+ <li>an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> zero or more of these.</li>
+</ul>
+<p>See <a href="#sets-and-lists" class="sec-ref"><span class="secno">4.9</span> <span class="sec-title">Sets and Lists</span></a> for a further discussion of List and Set Values.</p>
+</section>
+
+<section id="grammar-context">
+<h3><span class="secno">A.6 </span>Context Definition</h3>
+<p>A <dfn title="context_definition" id="dfn-context_definition">context definition</dfn> is a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>
+ containing one or more key-value pairs. Keys are non-keyword <a class="tref internalDFN" title="string" href="#dfn-string">strings</a>
+ or the <code>@language</code> or <code>@vocab</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keywords</a>.
+ A <a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">context definition</a>
+ <em class="rfc2119" title="should not">should not</em> contain any keys having the lexical form of <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a> other than
+ <code>@language</code> or <code>@vocab</code>.</p>
+<p>If the <a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">context definition</a> has a <code>@language</code> key,
+ the value <em class="rfc2119" title="must">must</em> have the lexical form described in [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] or be <a class="tref internalDFN" title="null" href="#dfn-null">null</a>.</p>
+<p>If the <a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">context definition</a> has a <code>@vocab</code> key,
+ the value <em class="rfc2119" title="must">must</em> have the lexical form of <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a> or be <a class="tref internalDFN" title="null" href="#dfn-null">null</a>.</p>
+<p>Other keys are <a class="tref internalDFN" title="term" href="#dfn-term">term</a> definitions. Their values <em class="rfc2119" title="must">must</em> be either a
+ <a class="tref internalDFN" title="string" href="#dfn-string">string</a>, or a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> having the form of an <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term
+ definition</a> (see <a href="#expanded-term-definition" class="sec-ref"><span class="secno">4.5</span> <span class="sec-title">Expanded Term Definition</span></a>).</p>
+<p>An <dfn title="expanded_term_definition" id="dfn-expanded_term_definition">expanded term definition</dfn> is composed of zero or more keys from <code>@id</code>,
+ <code>@type</code>, <code>@language</code> or <code>@container</code>. An
+ <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term definition</a> <em class="rfc2119" title="should not">should not</em> contain any other keys.
+ All values associated with <code>@id</code> <em class="rfc2119" title="must">must</em> expand to an <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</p>
+<p>If the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> definition is not a <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a> or <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ the <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term
+ definition</a> <em class="rfc2119" title="must">must</em> include the <code>@id</code> key.</p>
+<p>If the <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term definition</a> contains the <code>@id</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>,
+ it <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> having the lexical form of <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined in the defining <a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">context
+ definition</a> or the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>, or an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> composed of any of the previous allowed values.</p>
+<p>If the <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term definition</a> contains the <code>@type</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>,
+ it <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> having the lexical form of <a class="tref internalDFN" title="absolute_iri" href="#dfn-absolute_iri">absolute <abbr title="Internationalized Resource Identifier">IRI</abbr></a>,
+ <a class="tref internalDFN" title="compact_iri" href="#dfn-compact_iri">compact <abbr title="Internationalized Resource Identifier">IRI</abbr></a>, or a <a class="tref internalDFN" title="term" href="#dfn-term">term</a> defined in the defining <a class="tref internalDFN" title="context_definition" href="#dfn-context_definition">context
+ definition</a> or the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>.</p>
+<p>If the <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term definition</a> contains the <code>@language</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>,
+ the value <em class="rfc2119" title="must">must</em> have the lexical form described in [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] or be <a class="tref internalDFN" title="null" href="#dfn-null">null</a>.</p>
+<p>If the <a class="tref internalDFN" title="expanded_term_definition" href="#dfn-expanded_term_definition">expanded term definition</a> contains the <code>@container</code> <a class="tref internalDFN" title="keyword" href="#dfn-keyword">keyword</a>,
+ the value <em class="rfc2119" title="must">must</em> be either <code>@list</code>, <code>@set</code>, <code>@language</code>, or be <a class="tref internalDFN" title="null" href="#dfn-null">null</a>.
+ If the value is <code>@language</code>, when the <a class="tref internalDFN" title="term" href="#dfn-term">term</a> is used outside of the <code>@context</code>, the
+ associated value <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> whose keys are <a class="tref internalDFN" title="string" href="#dfn-string">string</a>s that are [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] language identifiers.
+ The values associated with each [<cite><a class="bibref" href="#bib-BCP47">BCP47</a></cite>] language string <em class="rfc2119" title="must">must</em> be a <a class="tref internalDFN" title="string" href="#dfn-string">string</a> or an <a class="tref internalDFN" title="array" href="#dfn-array">array</a> of <a class="tref internalDFN" title="string" href="#dfn-string">string</a>s.</p>
+<p>See <a href="#the-context" class="sec-ref"><span class="secno">3.5</span> <span class="sec-title">The Context</span></a> and <a href="#expanded-term-definition" class="sec-ref"><span class="secno">4.5</span> <span class="sec-title">Expanded Term Definition</span></a>
+ for a further discussion of contexts.</p>
+</section>
+<div class="example"><div class="example-title"><span>Example 68</span>: Context definition with simple terms, expanded term definitions and @language</div><pre class="example">{
+ "@language": "en",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "name": "foaf:name",
+ "depiction": {"@id": "foaf:depiction", "@type": "@id"},
+ "modified": {"@id": "http://purl.org/dc/terms/modified", "@type": "xsd:dateTime"},
+ "homepage": {"@id": "foaf:homepage", "@type": "@id", "@container": "@list"}
+}</pre></div>
+</section>
+
+<section class="appendix informative" id="relationship-to-other-linked-data-formats-and-data-models">
+
+<!--OddPage-->
+<h2><span class="secno">B. </span>Relationship to Other Linked Data Formats and Data Models</h2><p><em>This section is non-normative.</em></p>
+
+<div class="issue"><div class="issue-title"><span>Issue</span></div><p class="">
+The intent of the Working Group and the Editors of this specification is to
+eventually align terminology used in this document with the terminology used
+in the RDF Concepts document [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>] to the extent to which it makes sense to do so.
+In general, if there is an analogue to terminology used in this document in
+the RDF Concepts document, the preference is to use the terminology in the
+RDF Concepts document.
+</p></div>
+
+<p>JSON-LD is a specification for representing <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> in JSON. A common
+ way of working with Linked Data is through <dfn title="rdf" id="dfn-rdf">RDF</dfn>, the Resource Description Framework.
+ RDF can be expressed using JSON-LD by associating JSON-LD concepts such as <code>@id</code>
+ and <code>@type</code> with the equivalent <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s in RDF. Further information about
+ RDF may be found in the [<cite><a class="bibref" href="#bib-RDF-PRIMER">RDF-PRIMER</a></cite>].</p>
+
+<p>The JSON-LD markup examples below demonstrate how JSON-LD can be used to
+ express semantic data marked up in other languages and data models
+ such as RDF, Turtle, RDFa, Microformats,
+ and Microdata. These sections are merely provided as evidence that JSON-LD is
+ very flexible in what it can express across different <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> approaches.
+ Further information on transforming JSON-LD into RDF are detailed in the
+ [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>].</p>
+
+<section id="rdf">
+ <h3><span class="secno">B.1 </span>RDF</h3><p><em>This section is non-normative.</em></p>
+
+ <p>The RDF data model, as outlined in [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>], is an abstract
+ syntax for representing a directed graph of information. JSON-LD is
+ capable of serializing any RDF graph, and performing full RDF to
+ JSON-LD to RDF round-tripping. A complete description of how JSON-LD maps
+ to RDF and algorithms detailing how one can convert from RDF to
+ JSON-LD and from JSON-LD to RDF are included in the JSON-LD API
+ [<cite><a class="bibref" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>] specification.
+ </p>
+
+ <p>JSON-LD allows properties to be BNodes, while RDF does
+ not. Expressing properties as BNodes in JSON-LD only becomes an issue
+ (and could raise an exception) when it is transformed to RDF.</p>
+
+ <p>Note that the JSON-LD data model is silent on the topic of
+ <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled nodes</a>. Nevertheless,
+ this specification allows for the expression of
+ <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled nodes</a>, as most graph-based data
+ sets on the Web contain a number of associated nodes that are not named and
+ thus are not directly de-referenceable.
+ </p>
+
+<section id="turtle">
+ <h4><span class="secno">B.1.1 </span>Turtle</h4><p><em>This section is non-normative.</em></p>
+
+ <p>The following are examples of converting <a class="tref internalDFN" title="rdf" href="#dfn-rdf">RDF</a>
+ expressed in [<cite><a class="bibref" href="#bib-TURTLE-TR">TURTLE-TR</a></cite>] into JSON-LD.</p>
+
+<section id="prefix-definitions">
+<h5><span class="secno">B.1.1.1 </span>Prefix definitions</h5><p><em>This section is non-normative.</em></p>
+<p>The JSON-LD context has direct equivalents for the Turtle
+ <code>@prefix</code> declaration:</p>
+
+<div class="example"><div class="example-title"><span>Example 69</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+
+<http://manu.sporny.org/i/public> a foaf:Person;
+ foaf:name "Manu Sporny";
+ foaf:homepage <http://manu.sporny.org/> .</pre></div>
+
+<div class="example"><div class="example-title"><span>Example 70</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": { "@id": "http://manu.sporny.org/" }
+}</pre></div>
+
+<div class="note"><div class="note-title"><span>Note</span></div><p class="">JSON-LD has no equivalent for the Turtle <code>@base</code> declaration.</p></div>
+
+</section>
+
+<section id="embedding-1">
+<h5><span class="secno">B.1.1.2 </span>Embedding</h5>
+<p>Both Turtle and JSON-LD allow embedding, although Turtle only allows embedding of
+ <a class="tref internalDFN" title="unlabeled_node" href="#dfn-unlabeled_node">unlabeled nodes</a>.</p>
+</section>
+
+<div class="example"><div class="example-title"><span>Example 71</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+
+<http://manu.sporny.org/i/public>
+ a foaf:Person;
+ foaf:name "Manu Sporny";
+ foaf:knows [ a foaf:Person; foaf:name "Gregg Kellogg" ] .</pre></div>
+
+<div class="example"><div class="example-title"><span>Example 72</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://manu.sporny.org/i/public",
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:knows":
+ {
+ "@type": "foaf:Person",
+ "foaf:name": "Gregg Kellogg"
+ }
+}</pre></div>
+<section id="lists">
+<h5><span class="secno">B.1.1.3 </span>Lists</h5>
+<p>Both JSON-LD and Turtle can represent sequential lists of values.</p>
+
+<div class="example"><div class="example-title"><span>Example 73</span></div><pre class="example">@prefix foaf: <http://xmlns.com/foaf/0.1/> .
+
+<http://example.org/people#joebob> a foaf:Person;
+ foaf:name "Joe Bob";
+ foaf:nick ( "joe" "bob" "jaybee" ) .</pre></div>
+
+<div class="example"><div class="example-title"><span>Example 74</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": "http://example.org/people#joebob",
+ "@type": "foaf:Person",
+ "foaf:name": "Joe Bob",
+ "foaf:nick":
+ {
+ "@list": [ "joe", "bob", "jaybee" ]
+ }
+}</pre></div>
+</section>
+
+</section>
+
+<section id="rdfa">
+<h4><span class="secno">B.1.2 </span>RDFa</h4>
+
+<p>The following example describes three people with their respective names and
+homepages.</p>
+
+<div class="example"><div class="example-title"><span>Example 75</span></div><pre class="example"><div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>>
+ <ul>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name" </span>>Bob</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name" </span>>Eve</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name" </span>>Manu</a>
+ </li>
+ </ul>
+</div></pre></div>
+
+<p>An example JSON-LD implementation using a single <a class="tref internalDFN" title="context" href="#dfn-context">context</a> is
+described below.</p>
+
+<div class="example"><div class="example-title"><span>Example 76</span></div><pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@graph":
+ [
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/bob/",
+ "foaf:name": "Bob"
+ },
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/eve/",
+ "foaf:name": "Eve"
+ },
+ {
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/manu/",
+ "foaf:name": "Manu"
+ }
+ ]
+}</pre></div>
+
+</section>
+
+<section id="microformats">
+<h4><span class="secno">B.1.3 </span>Microformats</h4>
+
+<p>The following example uses a simple Microformats hCard example to express
+how the Microformat is represented in JSON-LD.</p>
+
+<div class="example"><div class="example-title"><span>Example 77</span></div><pre class="example"><div class="vcard">
+ <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</div></pre></div>
+
+<p>The representation of the hCard expresses the Microformat terms in the
+<a class="tref internalDFN" title="context" href="#dfn-context">context</a> and uses them directly for the <code>url</code> and <code>fn</code>
+properties. Also note that the Microformat to JSON-LD processor has
+generated the proper URL type for <code>http://tantek.com/</code>.</p>
+
+<div class="example"><div class="example-title"><span>Example 78</span></div><pre class="example">{
+ "@context":
+ {
+ "vcard": "http://microformats.org/profile/hcard#vcard",
+ "url":
+ {
+ "@id": "http://microformats.org/profile/hcard#url",
+ "@type": "@id"
+ },
+ "fn": "http://microformats.org/profile/hcard#fn"
+ },
+ "@type": "vcard",
+ "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+}</pre></div>
+
+</section>
+
+<section id="microdata">
+<h4><span class="secno">B.1.4 </span>Microdata</h4>
+
+<p>The microdata example below expresses book information as a microdata Work
+item.
+</p>
+
+<div class="example"><div class="example-title"><span>Example 79</span></div><pre class="example"><dl itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Work"
+ itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N">
+ <dt>Title</dt>
+ <dd><cite itemprop="http://purl.org/dc/terms/title">Just a Geek</cite></dd>
+ <dt>By</dt>
+ <dd><span itemprop="http://purl.org/dc/terms/creator">Wil Wheaton</span></dd>
+ <dt>Format</dt>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596007683.BOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK">
+ Print
+ </dd>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596802189.EBOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK">
+ Ebook
+ </dd>
+</dl></pre></div>
+
+<p>Note that the JSON-LD representation of the Microdata information stays
+true to the desires of the Microdata community to avoid contexts and
+instead refer to items by their full <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.</p>
+
+<div class="example"><div class="example-title"><span>Example 80</span></div><pre class="example">[
+ {
+ "@id": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
+ "@type": "http://purl.org/vocab/frbr/core#Work",
+ "http://purl.org/dc/terms/title": "Just a Geek",
+ "http://purl.org/dc/terms/creator": "Whil Wheaton",
+ "http://purl.org/vocab/frbr/core#realization":
+ [
+ "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "http://purl.oreilly.com/products/9780596802189.EBOOK"
+ ]
+ },
+ {
+ "@id": "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "@type": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
+ },
+ {
+ "@id": "http://purl.oreilly.com/products/9780596802189.EBOOK",
+ "@type": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
+ }
+]</pre></div>
+</section>
+</section>
+
+<section class="appendix informative" id="iana-considerations">
+<h3><span class="secno">B.2 </span>IANA Considerations</h3><p><em>This section is non-normative.</em></p>
+
+<p>This section is included merely for standards community review and will be
+submitted to the Internet Engineering Steering Group if this specification
+becomes a <abbr title="World Wide Web Consortium">W3C</abbr> Recommendation.</p>
+
+<h3 id="application-ld-json">application/ld+json</h3>
+<dl>
+ <dt>Type name:</dt>
+ <dd>application</dd>
+ <dt>Subtype name:</dt>
+ <dd>ld+json</dd>
+ <dt>Required parameters:</dt>
+ <dd>None</dd>
+ <dt>Optional parameters:</dt>
+ <dd>
+ <dl>
+ <dt><code>form</code></dt>
+ <dd>Determines the serialization form for the JSON-LD document. The only
+ valid value at the moment is <code>expanded</code>. If no form is
+ specified in an HTTP request header to an HTTP server, the server <em class="rfc2119" title="may">may</em>
+ choose any form. If no form is specified in an HTTP response, the form
+ <em class="rfc2119" title="must not">must not</em> be assumed to take any particular form.</dd>
+ </dl>
+ </dd>
+ <dt>Encoding considerations:</dt>
+ <dd>The same as the <code>application/json</code> MIME media type.</dd>
+ <dt>Security considerations:</dt>
+ <dd>Since JSON-LD is intended to be a pure data exchange format for
+ directed graphs, the serialization <em class="rfc2119" title="should not">should not</em> be passed through a
+ code execution mechanism such as JavaScript's <code>eval()</code>
+ function. It is <em class="rfc2119" title="recommended">recommended</em> that a conforming parser does not attempt to
+ directly evaluate the JSON-LD serialization and instead purely parse the
+ input into a language-native data structure. </dd>
+ <dt>Interoperability considerations:</dt>
+ <dd>Not Applicable</dd>
+ <dt>Published specification:</dt>
+ <dd>The <a href="http://json-ld.org/spec/latest/">JSON-LD</a> specification.</dd>
+ <dt>Applications that use this media type:</dt>
+ <dd>Any programming environment that requires the exchange of
+ directed graphs. Implementations of JSON-LD have been created for
+ JavaScript, Python, Ruby, PHP and C++.
+ </dd>
+ <dt>Additional information:</dt>
+ <dd>
+ <dl>
+ <dt>Magic number(s):</dt>
+ <dd>Not Applicable</dd>
+ <dt>File extension(s):</dt>
+ <dd>.jsonld</dd>
+ <dt>Macintosh file type code(s):</dt>
+ <dd>TEXT</dd>
+ </dl>
+ </dd>
+ <dt>Person & email address to contact for further information:</dt>
+ <dd>Manu Sporny <msporny@digitalbazaar.com></dd>
+ <dt>Intended usage:</dt>
+ <dd>Common</dd>
+ <dt>Restrictions on usage:</dt>
+ <dd>None</dd>
+ <dt>Author(s):</dt>
+ <dd>Manu Sporny, Gregg Kellogg, Markus Lanthaler, Dave Longley</dd>
+ <dt>Change controller:</dt>
+ <dd><abbr title="World Wide Web Consortium">W3C</abbr></dd>
+</dl>
+
+<p>Fragment identifiers used with <a href="#application-ld-json">application/ld+json</a>
+ resources <em class="rfc2119" title="may">may</em> identify a node in the <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a> expressed in
+ the resource. This idiom, which is also used in RDF [<cite><a class="bibref" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>], gives a
+ simple way to "mint" new, document-local IRIs to label nodes and therefore contributes
+ considerably to the expressive power of JSON-LD.</p>
+
+</section>
+
+<section class="appendix informative" id="acknowledgements">
+<h3><span class="secno">B.3 </span>Acknowledgements</h3><p><em>This section is non-normative.</em></p>
+
+<p>A large amount of thanks goes out to the JSON-LD Community Group
+participants who worked through many of the technical issues on the mailing
+list and the weekly telecons - of special mention are Niklas Lindström,
+François Daoust, and Zdenko 'Denny' Vrandečić.
+The editors would like to thank Mark Birbeck, who provided a great deal of
+the initial push behind the JSON-LD work via his work on RDFj.
+The work of Dave Lehn and Mike Johnson are appreciated for reviewing,
+and performing several implementations of the specification. Ian Davis is
+thanked for this work on RDF/JSON. Thanks also to Nathan Rixham,
+Bradley P. Allen,
+Kingsley Idehen, Glenn McDonald, Alexandre Passant, Danny Ayers, Ted
+Thibodeau Jr., Olivier Grisel, Josh Mandel, Eric Prud'hommeaux,
+David Wood, Guus Schreiber, Pat Hayes, Sandro Hawke, and Richard
+Cyganiak for their input on the specification.
+</p>
+</section>
+
+
+
+</section><section id="references" class="appendix">
+<!--OddPage-->
+<h2><span class="secno">C. </span>References</h2><section id="normative-references"><h3><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography"><dt id="bib-BCP47">[BCP47]</dt><dd>A. Phillips; M. Davis. <a href="http://tools.ietf.org/html/bcp47"><cite>Tags for Identifying Languages</cite></a> September 2009. IETF Best Current Practice. URL: <a href="http://tools.ietf.org/html/bcp47">http://tools.ietf.org/html/bcp47</a>
+</dd><dt id="bib-RDF-CONCEPTS">[RDF-CONCEPTS]</dt><dd><cite><a href="http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/">RDF 1.1 Concepts and Abstract Syntax</a></cite> Richard Cyganiak, David Wood, Editors. World Wide Web Consortium (work in progress). 30 May 2012. Editor's Draft. This edition of the JSON-LD Syntax specification is http://www.w3.org/TR/2011/WD-rdf11-concepts-20110830/. The <a href="http://www.w3.org/TR/rdf11-concepts/">latest edition of the JSON-LD Syntax</a> is available at http://www.w3.org/TR/rdf11-concepts/
+</dd><dt id="bib-RFC3987">[RFC3987]</dt><dd>M. Dürst; M. Suignard. <a href="http://www.ietf.org/rfc/rfc3987.txt"><cite>Internationalized Resource Identifiers (IRIs).</cite></a> January 2005. Internet RFC 3987. URL: <a href="http://www.ietf.org/rfc/rfc3987.txt">http://www.ietf.org/rfc/rfc3987.txt</a>
+</dd><dt id="bib-RFC4627">[RFC4627]</dt><dd>D. Crockford. <a href="http://www.ietf.org/rfc/rfc4627.txt"><cite>The application/json Media Type for JavaScript Object Notation (JSON)</cite></a> July 2006. Internet RFC 4627. URL: <a href="http://www.ietf.org/rfc/rfc4627.txt">http://www.ietf.org/rfc/rfc4627.txt</a>
+</dd><dt id="bib-RFC5988">[RFC5988]</dt><dd><cite><a href="http://tools.ietf.org/rfc/rfc5988">Web Linking</a></cite> M. Nottingham. Editor. October 2010. IETF Standard. URL: <a href="http://tools.ietf.org/rfc/rfc5988.txt">http://tools.ietf.org/rfc/rfc5988.txt</a>
+</dd></dl></section><section id="informative-references"><h3><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography"><dt id="bib-JSON-LD-API">[JSON-LD-API]</dt><dd><cite><a href="http://json-ld.org/spec/ED/json-ld-api/20120524/">The JSON-LD API 1.0</a></cite> Manu Sporny, Gregg Kellogg, Dave Longley, Markus Lanthaler, Editors. World Wide Web Consortium (work in progress). 24 May 2012. Editor's Draft. This edition of the JSON-LD Syntax specification is http://json-ld.org/spec/ED/json-ld-api/20120524/. The <a href="http://json-ld.org/spec/latest/json-ld-api/">latest edition of the JSON-LD Syntax</a> is available at http://json-ld.org/spec/latest/json-ld-api/
+</dd><dt id="bib-RDF-PRIMER">[RDF-PRIMER]</dt><dd>Frank Manola; Eric Miller. <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/"><cite>RDF Primer.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-primer-20040210/">http://www.w3.org/TR/2004/REC-rdf-primer-20040210/</a>
+</dd><dt id="bib-RDF-SPARQL-QUERY">[RDF-SPARQL-QUERY]</dt><dd>Andy Seaborne; Eric Prud'hommeaux. <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115"><cite>SPARQL Query Language for RDF.</cite></a> 15 January 2008. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115">http://www.w3.org/TR/2008/REC-rdf-sparql-query-20080115</a>
+</dd><dt id="bib-RDFA-CORE">[RDFA-CORE]</dt><dd>Shane McCarron; et al. <a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/"><cite>RDFa Core 1.1: Syntax and processing rules for embedding RDF through attributes.</cite></a> 7 June 2012. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2012/REC-rdfa-core-20120607/">http://www.w3.org/TR/2012/REC-rdfa-core-20120607/</a>
+</dd><dt id="bib-TURTLE-TR">[TURTLE-TR]</dt><dd>Eric Prud'hommeaux, Gavin Carothers. <cite><a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">Turtle: Terse RDF Triple Language.</a></cite> 09 August 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-turtle-20110809/">http://www.w3.org/TR/2011/WD-turtle-20110809/</a>
+</dd></dl></section></section></body></html>
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