--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/ED/json-ld-syntax/20120122/diff-20120112.html Sun Jan 22 14:59:39 2012 -0500
@@ -0,0 +1,10934 @@
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+
+</style><style type="text/css">ol.algorithm { counter-reset:numsection; list-style-type: none; }
+ol.algorithm li { margin: 0.5em 0; }
+ol.algorithm li:before { font-weight: bold; counter-increment: numsection; content: counters(numsection, ".") ") "; }
+
+</style><link href="http://www.w3.org/StyleSheets/TR/w3c-unofficial" rel="stylesheet" type="text/css" charset="utf-8" /><style type='text/css'>
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+ font-size: smaller;
+ color: red;
+}
+
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+.diff-new:before,
+.diff-new:after
+ { content: "\2191" }
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+ { content: "\2195" }
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+.diff-old:before,
+.diff-old:after
+ { content: "\2193" }
+:focus { border: thin red solid}
+</style>
+</head>
+
+
+<body style="display: inherit; ">
+<div class="head">
+<p>
+</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="unofficial-draft-22-january-2012">
+Unofficial
+Draft
+22
+January
+2012
+</h2>
+<dl>
+<dt>
+Editors:
+</dt>
+<dd>
+<a href="http://manu.sporny.org/">
+Manu
+Sporny
+</a>,
+<a href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</dd>
+<dd>
+<a href="http://greggkellogg.net/">
+Gregg
+Kellogg
+</a>,
+<a href="http://kellogg-assoc.com/">
+Kellogg
+Associates
+</a>
+</dd>
+<dt>
+Authors:
+</dt>
+<dd>
+<a href="http://digitalbazaar.com/">
+Manu
+Sporny
+</a>,
+<a href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</dd>
+<dd>
+<a href="http://digitalbazaar.com/">
+Dave
+Longley
+</a>,
+<a href="http://digitalbazaar.com/">
+Digital
+Bazaar
+</a>
+</dd>
+<dd>
+<a href="http://greggkellogg.net/">
+Gregg
+Kellogg
+</a>,
+<a href="http://kellogg-assoc.com/">
+Kellogg
+Associates
+</a>
+</dd>
+<dd>
+<a href="http://www.markus-lanthaler.com/">
+Markus
+Lanthaler
+</a>,
+<a href="http://www.tugraz.at/">
+Graz
+University
+of
+Technology
+</a>
+</dd>
+<dd>
+<a href="http://webbackplane.com/">
+Mark
+Birbeck
+</a>,
+<a href="http://webbackplane.com/">
+Backplane
+Ltd.
+</a>
+</dd>
+</dl>
+<p>
+This
+document
+is
+also
+available
+in
+this
+non-normative
+format:
+<a href="diff-20111023.html">
+diff
+to
+previous
+version
+</a>.
+</p>
+<p class="copyright">
+This
+document
+is
+licensed
+under
+a
+<a class="subfoot" href="http://creativecommons.org/licenses/by/3.0/" rel="license">
+Creative
+Commons
+Attribution
+3.0
+License
+</a>.
+</p>
+<hr />
+</div>
+<div id="abstract" class="introductory section">
+<h2>
+Abstract
+</h2>
+<p>
+JSON
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+]
+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>
+</div>
+<div id="sotd" class="introductory section">
+<h2>
+Status
+of
+This
+Document
+</h2>
+<p>
+This
+document
+is
+merely
+a
+public
+working
+draft
+of
+a
+potential
+specification.
+It
+has
+no
+official
+standing
+of
+any
+kind
+and
+does
+not
+represent
+the
+support
+or
+consensus
+of
+any
+standards
+organisation.
+</p>
+<p>
+This
+document
+is
+an
+experimental
+work
+in
+progress.
+</p>
+</div>
+<div id="toc" class="section">
+<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>
+<li class="tocline">
+<a href="#syntax-tokens-and-keywords" class="tocxref">
+<span class="secno">
+1.2
+</span>
+Syntax
+Tokens
+and
+Keywords
+</a>
+</li>
+<li class="tocline">
+<a href="#contributing" class="tocxref">
+<span class="secno">
+1.3
+</span>
+Contributing
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#design" class="tocxref">
+<span class="secno">
+2.
+</span>
+Design
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#goals-and-rationale" class="tocxref">
+<span class="secno">
+2.1
+</span>
+Goals
+and
+Rationale
+</a>
+</li>
+<li class="tocline">
+<a href="#linking-data" class="tocxref">
+<span class="secno">
+2.2
+</span>
+Linking
+Data
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#the-context" class="tocxref">
+<span class="secno">
+2.2.1
+</span>
+The
+Context
+</a>
+</li>
+<li class="tocline">
+<a href="#from-json-to-json-ld" class="tocxref">
+<span class="secno">
+2.2.2
+</span>
+From
+JSON
+to
+JSON-LD
+</a>
+</li>
+</ul>
+</li>
+</ul>
+</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="#iris" class="tocxref">
+<span class="secno">
+3.1
+</span>
+IRIs
+</a>
+</li>
+<li class="tocline">
+<a href="#identifying-the-subject" class="tocxref">
+<span class="secno">
+3.2
+</span>
+Identifying
+the
+Subject
+</a>
+</li>
+<li class="tocline">
+<a href="#specifying-the-type" class="tocxref">
+<span class="secno">
+3.3
+</span>
+Specifying
+the
+Type
+</a>
+</li>
+<li class="tocline">
+<a href="#strings" class="tocxref">
+<span class="secno">
+3.4
+</span>
+Strings
+</a>
+</li>
+<li class="tocline">
+<a href="#string-internationalization" class="tocxref">
+<span class="secno">
+3.5
+</span>
+String
+Internationalization
+</a>
+</li>
+<li class="tocline">
+<a href="#typed-values" class="tocxref">
+<span class="secno">
+3.6
+</span>
+Typed
+Values
+</a>
+</li>
+<li class="tocline">
+<a href="#multiple-objects-for-a-single-property" class="tocxref">
+<span class="secno">
+3.7
+</span>
+Multiple
+Objects
+for
+a
+Single
+Property
+</a>
+</li>
+<li class="tocline">
+<a href="#multiple-values-for-a-single-property" class="tocxref">
+<span class="secno">
+3.8
+</span>
+Multiple
+Values
+for
+a
+Single
+Property
+</a>
+</li>
+<li class="tocline">
+<a href="#lists" class="tocxref">
+<span class="secno">
+3.9
+</span>
+Lists
+</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="#prefixes" class="tocxref">
+<span class="secno">
+4.1
+</span>
+Prefixes
+</a>
+</li>
+<li class="tocline">
+<a href="#external-contexts" class="tocxref">
+<span class="secno">
+4.2
+</span>
+External
+Contexts
+</a>
+</li>
+<li class="tocline">
+<a href="#default-language" class="tocxref">
+<span class="secno">
+4.3
+</span>
+Default
+Language
+</a>
+</li>
+<li class="tocline">
+<a href="#expanded-term-definition" class="tocxref">
+<span class="secno">
+4.4
+</span>
+Expanded
+Term
+Definition
+</a>
+</li>
+<li class="tocline">
+<a href="#automatic-typing" class="tocxref">
+<span class="secno">
+4.5
+</span>
+Automatic
+Typing
+</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="#iri-expansion-within-a-context" class="tocxref">
+<span class="secno">
+4.7
+</span>
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+Expansion
+Within
+a
+Context
+</a>
+</li>
+<li class="tocline">
+<a href="#embedding" class="tocxref">
+<span class="secno">
+4.8
+</span>
+Embedding
+</a>
+</li>
+<li class="tocline">
+<a href="#identifying-unlabeled-nodes" class="tocxref">
+<span class="secno">
+4.9
+</span>
+Identifying
+Unlabeled
+Nodes
+</a>
+</li>
+<li class="tocline">
+<a href="#aliasing-keywords" class="tocxref">
+<span class="secno">
+4.10
+</span>
+Aliasing
+Keywords
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#markup-examples" class="tocxref">
+<span class="secno">
+A.
+</span>
+Markup
+Examples
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#turtle" class="tocxref">
+<span class="secno">
+A.1
+</span>
+Turtle
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#prefix-definitions" class="tocxref">
+<span class="secno">
+A.1.1
+</span>
+Prefix
+definitions
+</a>
+</li>
+<li class="tocline">
+<a href="#embedding-1" class="tocxref">
+<span class="secno">
+A.1.2
+</span>
+Embedding
+</a>
+</li>
+<li class="tocline">
+<a href="#lists-1" class="tocxref">
+<span class="secno">
+A.1.3
+</span>
+Lists
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#rdfa" class="tocxref">
+<span class="secno">
+A.2
+</span>
+RDFa
+</a>
+</li>
+<li class="tocline">
+<a href="#microformats" class="tocxref">
+<span class="secno">
+A.3
+</span>
+Microformats
+</a>
+</li>
+<li class="tocline">
+<a href="#microdata" class="tocxref">
+<span class="secno">
+A.4
+</span>
+Microdata
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#linked-data" class="tocxref">
+<span class="secno">
+B.
+</span>
+Linked
+Data
+</a>
+</li>
+<li class="tocline">
+<a href="#mashing-up-vocabularies" class="tocxref">
+<span class="secno">
+C.
+</span>
+Mashing
+Up
+Vocabularies
+</a>
+</li>
+<li class="tocline">
+<a href="#iana-considerations" class="tocxref">
+<span class="secno">
+D.
+</span>
+IANA
+Considerations
+</a>
+</li>
+<li class="tocline">
+<a href="#acknowledgements" class="tocxref">
+<span class="secno">
+E.
+</span>
+Acknowledgements
+</a>
+</li>
+<li class="tocline">
+<a href="#references" class="tocxref">
+<span class="secno">
+F.
+</span>
+References
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#normative-references" class="tocxref">
+<span class="secno">
+F.1
+</span>
+Normative
+references
+</a>
+</li>
+<li class="tocline">
+<a href="#informative-references" class="tocxref">
+<span class="secno">
+F.2
+</span>
+Informative
+references
+</a>
+</li>
+</ul>
+</li>
+</ul>
+</div>
+<div class="informative section" 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" rel="biblioentry" 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
+graph
+of
+interlinked
+data
+across
+different
+documents
+or
+Web
+sites.
+Data
+entities
+are
+described
+using
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s,
+which
+are
+typically
+dereferencable
+and
+thus
+may
+be
+used
+to
+find
+more
+information
+about
+an
+entity,
+creating
+a
+"Web
+of
+Knowledge".
+JSON-LD
+is
+intended
+to
+be
+a
+simple
+publishing
+method
+for
+expressing
+not
+only
+Linked
+Data
+in
+JSON,
+but
+also
+for
+adding
+semantics
+to
+existing
+JSON.
+</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
+interoperable
+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
+with
+added
+semantics.
+Finally,
+the
+format
+is
+intended
+to
+be
+easy
+to
+parse,
+efficient
+to
+generate,
+and
+only
+requires
+a
+very
+small
+memory
+footprint
+in
+order
+to
+operate.
+</p>
+<div id="how-to-read-this-document" class="section">
+<h3>
+<span class="secno">
+1.1
+</span>
+How
+to
+Read
+this
+Document
+</h3>
+<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
+way
+that
+is
+cross-language
+compatible
+via
+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" rel="biblioentry" 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" rel="biblioentry" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+].
+To
+understand
+the
+API
+and
+how
+it
+is
+intended
+to
+operate
+in
+a
+programming
+environment,
+it
+is
+useful
+to
+have
+working
+knowledge
+of
+the
+JavaScript
+programming
+language
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-ECMA-262">
+ECMA-262
+</a>
+</cite>
+]
+and
+WebIDL
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-WEBIDL">
+WEBIDL
+</a>
+</cite>
+].
+</p>
+<p>
+JSON
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RFC4627">
+RFC4627
+</a>
+</cite>
+]
+defines
+several
+terms
+which
+are
+used
+throughout
+this
+document:
+</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
+name/value
+pairs
+(or
+members).
+A
+name
+is
+a
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>.
+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
+<em class="rfc2119" title="should">
+should
+</em>
+be
+unique.
+</dd>
+<dt>
+<dfn title="array" id="dfn-array">
+array
+</dfn>
+</dt>
+<dd>
+An
+array
+is
+an
+ordered
+collection
+of
+values.
+An
+array
+structure
+is
+represented
+as
+square
+brackets
+surrounding
+zero
+or
+more
+values
+(or
+elements).
+Elements
+are
+separated
+by
+commas.
+Within
+JSON-LD,
+array
+order
+is
+not
+preserved
+by
+default,
+unless
+specific
+markup
+is
+provided
+(see
+<a href="#lists">
+Lists
+</a>
+).
+This
+is
+because
+the
+basic
+data
+model
+of
+JSON-LD
+is
+a
+<a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">
+linked
+data
+graph
+</a>,
+which
+is
+inherently
+unordered.
+</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.
+A
+character
+is
+represented
+as
+a
+single
+character
+string.
+</dd>
+<dt>
+<dfn title="number" id="dfn-number">
+number
+</dfn>
+</dt>
+<dd>
+A
+number
+is
+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
+use
+of
+the
+<em>
+null
+</em>
+value
+is
+undefined
+within
+JSON-LD.
+</dd>
+</dl>
+<p>
+</p>
+</div>
+<div id="syntax-tokens-and-keywords" class="section">
+<h3>
+<span class="secno">
+1.2
+</span>
+Syntax
+Tokens
+and
+Keywords
+</h3>
+<p>
+JSON-LD
+specifies
+a
+number
+of
+syntax
+tokens
+and
+keywords
+that
+are
+using
+in
+all
+algorithms
+described
+in
+this
+section:
+</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
+express
+specific
+identifiers
+in
+a
+compact
+manner.
+The
+<code>
+@context
+</code>
+keyword
+is
+described
+in
+detail
+in
+the
+section
+titled
+<a href="#the-context">
+The
+Context
+</a>.
+</dd>
+<dt>
+<code>
+@id
+</code>
+</dt>
+<dd>
+Used
+to
+uniquely
+identify
+things
+that
+are
+being
+described
+in
+the
+document.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#identifying-the-subject">
+Identifying
+the
+Subject
+</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
+the
+sections
+titled
+<a href="#string-internationalization">
+String
+Internationalization
+</a>
+and
+<a href="#typed-values">
+Typed
+Values
+</a>.
+</dd>
+<dt>
+<code>
+@language
+</code>
+</dt>
+<dd>
+Used
+to
+specify
+the
+native
+language
+for
+a
+particular
+value.
+This
+keyword
+is
+described
+in
+the
+section
+titled
+<a href="#string-internationalization">
+String
+Internationalization
+</a>.
+</dd>
+<dt>
+<code>
+@type
+</code>
+</dt>
+<dd>
+Used
+to
+set
+the
+data
+type
+of
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</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">
+Typed
+Values
+</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="#lists">
+Lists
+</a>.
+</dd>
+<dt>
+<code>:
+</code>
+</dt>
+<dd>
+The
+separator
+for
+JSON
+keys
+and
+values
+that
+use
+the
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+mechanism.
+</dd>
+</dl>
+</div>
+<div id="contributing" class="section">
+<h3>
+<span class="secno">
+1.3
+</span>
+Contributing
+</h3>
+<p>
+There
+are
+a
+number
+of
+ways
+that
+one
+may
+participate
+in
+the
+development
+of
+this
+specification:
+</p>
+<ul>
+<li>
+Technical
+discussion
+typically
+occurs
+on
+the
+public
+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
+teleconferences
+</a>
+are
+held
+every
+week
+on
+Tuesdays
+at
+1500
+UTC.
+</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>.
+</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>
+</div>
+</div>
+<div class="informative section" id="design">
+<h2>
+<span class="secno">
+2.
+</span>
+Design
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+The
+following
+section
+outlines
+the
+design
+goals
+and
+rationale
+behind
+the
+JSON-LD
+markup
+language.
+</p>
+<div id="goals-and-rationale" class="section">
+<h3>
+<span class="secno">
+2.1
+</span>
+Goals
+and
+Rationale
+</h3>
+<p>
+A
+number
+of
+design
+considerations
+were
+explored
+during
+the
+creation
+of
+this
+markup
+language:
+</p>
+<dl>
+<dt>
+Simplicity
+</dt>
+<dd>
+Developers
+need
+only
+know
+JSON
+and
+two
+keywords
+(
+<code>
+@context
+</code>
+and
+<code>
+@id
+</code>
+)
+to
+use
+the
+basic
+functionality
+in
+JSON-LD.
+No
+extra
+processors
+or
+software
+libraries
+are
+necessary
+to
+use
+JSON-LD
+in
+its
+most
+basic
+form.
+The
+language
+attempts
+to
+ensure
+that
+developers
+have
+an
+easy
+learning
+curve.
+</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
+simply
+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
+provides
+a
+mechanism
+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
+esoteric
+markup,
+we
+chose
+not
+to
+support
+the
+use
+case
+and
+support
+a
+simplified
+syntax
+instead.
+So,
+while
+Zero
+Edits
+is
+a
+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>
+</dl>
+</div>
+<div id="linking-data" class="section">
+<h3>
+<span class="secno">
+2.2
+</span>
+Linking
+Data
+</h3>
+<p>
+An
+Internationalized
+Resource
+Identifier
+(
+<dfn title="iri" id="dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</dfn>
+),
+as
+described
+in
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RFC3987">
+RFC3987
+</a>
+</cite>
+],
+is
+a
+mechanism
+for
+representing
+unique
+identifiers
+on
+the
+web.
+In
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>,
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+commonly
+used
+for
+expressing
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>,
+a
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>
+or
+an
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>.
+</p>
+<p>
+JSON-LD
+defines
+a
+mechanism
+to
+map
+JSON
+terms,
+i.e.,
+keys
+and
+values,
+to
+IRIs.
+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>.
+There
+are
+a
+few
+techniques
+that
+can
+ensure
+that
+developers
+will
+generate
+good
+Linked
+Data
+for
+the
+Web.
+JSON-LD
+formalizes
+those
+techniques.
+</p>
+<p>
+We
+will
+be
+using
+the
+following
+JSON
+markup
+as
+the
+example
+for
+the
+rest
+of
+this
+section:
+</p>
+<pre class="example">{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+<div id="the-context" class="section">
+<h4>
+<span class="secno">
+2.2.1
+</span>
+The
+Context
+</h4>
+<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.,
+keys
+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
+<em class="rfc2119" title="may">
+may
+</em>
+be
+expanded
+to
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+A
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+<em class="rfc2119" title="must">
+must
+</em>
+have
+the
+lexical
+form
+of
+<cite>
+<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">
+NCName
+</a>
+</cite>
+(see
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">
+XML-NAMES
+</a>
+</cite>
+]),
+or
+be
+an
+empty
+string.
+</p>
+<p>
+The
+Web
+uses
+IRIs
+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
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+terms.
+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
+name/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
+absolute
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or,
+2)
+an
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+containing
+an
+<code>
+@id
+</code>,
+<code>
+@type
+</code>,
+or
+<code>
+@list
+</code>
+keyword.
+</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>
+<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>
+<p>
+This
+context
+document
+can
+then
+be
+used
+in
+an
+JSON-LD
+document
+by
+adding
+a
+single
+line.
+The
+JSON
+markup
+as
+shown
+in
+the
+previous
+section
+could
+be
+changed
+as
+follows
+to
+link
+to
+the
+context
+document:
+</p>
+<pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person",</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+<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
+IRIs.
+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>
+<p>
+Contexts
+may
+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>
+<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>
+<p>
+Contexts
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+at
+any
+time
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+is
+defined.
+A
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</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
+array-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>
+<p>
+The
+set
+of
+contexts
+defined
+within
+a
+specific
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+Object
+</a>
+are
+referred
+to
+as
+<dfn title="local_context" id="dfn-local_context">
+local
+context
+</dfn>
+s.
+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>
+<pre class="example">{
+ <span class="diff">"@context": [
+ "http://json-ld.org/contexts/person",
+ {
+ "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>
+<p>
+JSON-LD
+uses
+a
+special
+type
+of
+machine-readable
+document
+called
+a
+<dfn title="vocabulary" id="dfn-vocabulary">
+vocabulary
+</dfn>
+to
+define
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+that
+are
+then
+used
+to
+describe
+concepts
+and
+"things"
+in
+the
+world.
+Typically,
+these
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+documents
+have
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+es
+associated
+with
+them
+and
+contain
+a
+number
+of
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+declarations.
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+Prefix
+</a>
+es
+are
+helpful
+when
+a
+developer
+wants
+to
+mix
+multiple
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+together
+in
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>,
+but
+does
+not
+want
+to
+go
+to
+the
+trouble
+of
+defining
+every
+single
+term
+in
+every
+single
+vocabulary.
+Some
+Web
+Vocabularies
+may
+have
+dozens
+of
+terms
+defined.
+If
+a
+developer
+wants
+to
+use
+3-4
+different
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>,
+the
+number
+of
+terms
+that
+would
+have
+to
+be
+declared
+in
+a
+single
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+could
+become
+quite
+large.
+To
+reduce
+the
+number
+of
+different
+terms
+that
+must
+be
+defined,
+JSON-LD
+also
+allows
+prefixes
+to
+be
+used
+to
+compact
+IRIs.
+</p>
+<p>
+For
+example,
+the
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+<code>
+http://xmlns.com/foaf/0.1/
+</code>
+specifies
+a
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+which
+may
+be
+represented
+using
+the
+<code>
+foaf
+</code>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>.
+The
+<code>
+foaf
+</code>
+vocabulary
+contains
+a
+term
+called
+<strong>
+name
+</strong>.
+If
+you
+join
+the
+<code>
+foaf
+</code>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+with
+the
+<strong>
+name
+</strong>
+suffix,
+you
+can
+build
+a
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+that
+will
+expand
+out
+into
+an
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+for
+the
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+term.
+That
+is,
+the
+compact
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+(or
+short-form),
+is
+<code>
+foaf:name
+</code>
+and
+the
+expanded-form
+is
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>.
+This
+vocabulary
+term
+is
+used
+to
+specify
+a
+person's
+name.
+</p>
+<p>
+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.
+Much
+like
+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.
+IRIs
+provide
+a
+way
+to
+ensure
+that
+these
+terms
+are
+unambiguous.
+</p>
+<p>
+The
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+provides
+a
+collection
+of
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+s
+and
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+es
+that
+can
+be
+used
+to
+expand
+JSON
+keys
+and
+values
+into
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s.
+</p>
+<p class="note">
+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
+one-pass
+processors.
+</p>
+</div>
+<div id="from-json-to-json-ld" class="section">
+<h4>
+<span class="secno">
+2.2.2
+</span>
+From
+JSON
+to
+JSON-LD
+</h4>
+<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
+JSON
+objects,
+machines
+are
+able
+to
+automatically
+expand
+the
+terms
+to
+something
+meaningful
+and
+unambiguous,
+like
+this:
+</p>
+<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://rdfs.org/sioc/ns#avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+<p>
+Doing
+this
+allows
+JSON
+to
+be
+unambiguously
+machine-readable
+without
+requiring
+developers
+to
+drastically
+change
+their
+workflow.
+</p>
+<p class="note">
+The
+example
+above
+does
+not
+use
+the
+<code>
+@id
+</code>
+keyword
+to
+set
+the
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+of
+the
+node
+being
+described
+above.
+This
+type
+of
+node
+is
+called
+an
+<dfn title="unlabeled_node" id="dfn-unlabeled_node">
+unlabeled
+node
+</dfn>
+and
+is
+considered
+to
+be
+a
+weaker
+form
+of
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</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>
+</div>
+</div>
+<div id="basic-concepts" class="section">
+<h2>
+<span class="secno">
+3.
+</span>
+Basic
+Concepts
+</h2>
+<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>
+<div id="iris" class="section">
+<h3>
+<span class="secno">
+3.1
+</span>
+IRIs
+</h3>
+<p>
+Expressing
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+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="subject" href="#dfn-subject">
+subject
+</a>
+s,
+all
+<a class="tref internalDFN" title="property" href="#dfn-property">
+properties
+</a>
+and
+many
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+s
+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>
+<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
+to
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+or
+another
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+are
+expanded
+to
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+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
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>,
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+that
+is
+relative
+to
+the
+base
+location
+of
+the
+document,
+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>:suffix
+construct.
+</p>
+<p>
+IRIs
+can
+be
+expressed
+directly
+in
+the
+key
+position
+like
+so:
+</p>
+<pre class="example">{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}
+</pre>
+<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>,
+as
+opposed
+to
+being
+interpreted
+as
+a
+string.
+</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>
+<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",
+...
+}
+</pre>
+<p>
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+Prefix
+</a>
+es
+are
+expanded
+when
+the
+form
+of
+the
+value
+is
+<code>
+prefix:suffix
+</code>,
+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>
+<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>
+<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>
+<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="#prefixes">
+Prefixes
+</a>
+for
+more
+details.
+</p>
+<p>
+An
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+is
+generated
+when
+a
+value
+is
+associated
+with
+a
+key
+using
+the
+<code>
+@id
+</code>
+keyword:
+</p>
+<pre class="example">{
+...
+ "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
+...
+}
+</pre>
+<p class="note">
+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
+object
+using
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+This
+facility
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+to
+link
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+with
+an
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</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">
+Embedding
+</a>.
+</p>
+<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>
+<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>
+<p>
+Even
+though
+the
+value
+<code>
+http://manu.sporny.org/
+</code>
+is
+a
+<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>
+</div>
+<div id="identifying-the-subject" class="section">
+<h3>
+<span class="secno">
+3.2
+</span>
+Identifying
+the
+Subject
+</h3>
+<p>
+To
+be
+able
+to
+externally
+reference
+nodes,
+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.
+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>
+A
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+of
+an
+object
+in
+JSON
+is
+declared
+using
+the
+<code>
+@id
+</code>
+key.
+The
+subject
+is
+the
+first
+piece
+of
+information
+needed
+by
+the
+JSON-LD
+processor
+in
+order
+to
+create
+the
+(subject,
+property,
+object)
+tuple,
+also
+known
+as
+a
+triple.
+</p>
+<pre class="example">{
+...
+ "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+set
+the
+subject
+to
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<code>
+http://example.org/people#joebob
+</code>.
+</p>
+<p class="note">
+To
+ensure
+the
+best
+possible
+performance,
+it
+is
+a
+best
+practice
+to
+put
+the
+<code>
+@id
+</code>
+keyword
+before
+other
+key-value
+pairs
+in
+an
+object.
+If
+it
+isn't
+listed
+first,
+processors
+have
+to
+save
+each
+key-value
+pair
+until
+<code>
+@id
+</code>
+is
+processed
+before
+they
+can
+start
+generating
+triples.
+Not
+specifying
+the
+<code>
+@id
+</code>
+keyword
+first
+creates
+a
+memory
+and
+complexity
+burden
+for
+one-pass
+processors.
+</p>
+</div>
+<div id="specifying-the-type" class="section">
+<h3>
+<span class="secno">
+3.3
+</span>
+Specifying
+the
+Type
+</h3>
+<p>
+The
+type
+of
+a
+particular
+subject
+can
+be
+specified
+using
+the
+<code>
+@type
+</code>
+keyword.
+Specifying
+the
+type
+in
+this
+way
+will
+generate
+a
+triple
+of
+the
+form
+(subject,
+type,
+type-
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+).
+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>
+<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>
+<div id="strings" class="section">
+<h3>
+<span class="secno">
+3.4
+</span>
+Strings
+</h3>
+<p>
+Regular
+text
+strings,
+also
+referred
+to
+as
+<dfn title="string_value" id="dfn-string_value">
+string
+value
+</dfn>
+s,
+are
+easily
+expressed
+using
+regular
+JSON
+<a class="tref internalDFN" title="string" href="#dfn-string">
+string
+</a>
+s.
+</p>
+<pre class="example">{
+...
+ "name": "<span class="diff">Mark Birbeck</span>",
+...
+}
+</pre>
+</div>
+<div id="string-internationalization" class="section">
+<h3>
+<span class="secno">
+3.5
+</span>
+String
+Internationalization
+</h3>
+<p>
+JSON-LD
+makes
+an
+assumption
+that
+strings
+with
+associated
+language
+encoding
+information
+are
+not
+very
+common
+when
+used
+in
+JavaScript
+and
+Web
+Services.
+Thus,
+it
+takes
+a
+little
+more
+effort
+to
+express
+strings
+with
+associated
+language
+information.
+</p>
+<pre class="example">{
+...
+ "name": <span class="diff">
+ {
+ "@value": "花澄",
+ "@language": "ja"
+ }</span>
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+a
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+for
+<em>
+花澄
+</em>
+and
+associate
+the
+<code>
+ja
+</code>
+language
+code
+with
+the
+triple
+that
+is
+generated.
+Languages
+<em class="rfc2119" title="must">
+must
+</em>
+be
+expressed
+in
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-BCP47">
+BCP47
+</a>
+</cite>
+]
+format.
+</p>
+</div>
+<div id="typed-values" class="section">
+<h3>
+<span class="secno">
+3.6
+</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>
+keyword
+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
+objects.
+</li>
+<li>
+By
+using
+a
+native
+JSON
+type.
+</li>
+</ol>
+<p>
+The
+first
+example
+uses
+the
+<code>
+@type
+</code>
+keyword
+to
+express
+a
+typed
+value:
+</p>
+<pre class="example">{
+ <span class="diff">"@context": {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "modified": {
+ "@id": "http://purl.org/dc/terms/modified",
+ "@type": "xsd:dateTime"
+ }
+ }</span>
+...
+ "modified": "2010-05-29T14:17:39+02:00",
+...
+}
+</pre>
+<p>
+The
+second
+example
+uses
+the
+expanded
+form
+for
+specifying
+objects:
+</p>
+<pre class="example">{
+...
+ "modified": <span class="diff">{
+ "@value": "2010-05-29T14:17:39+02:00",
+ "@type": "xsd:dateTime"
+ }</span>
+...
+}
+</pre>
+<p>
+Both
+examples
+above
+would
+generate
+an
+object
+with
+the
+value
+of
+<code>
+2010-05-29T14:17:39+02:00
+</code>
+and
+the
+type
+of
+<code>
+http://www.w3.org/2001/XMLSchema#dateTime
+</code>.
+</p>
+<p>
+The
+third
+example
+uses
+a
+built-in
+native
+JSON
+type,
+a
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>,
+to
+express
+a
+type:
+</p>
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "age": <span class="diff">31</span>
+...
+}
+</pre>
+<p>
+The
+example
+above
+is
+really
+just
+a
+shorthand
+for
+the
+following:
+</p>
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "age": <span class="diff">{
+ "@value": "31",
+ "@type": "http://www.w3.org/2001/XMLSchema#integer"
+ }</span>
+...
+}
+</pre>
+<p class="note">
+The
+<code>
+@type
+</code>
+keyword
+is
+also
+used
+to
+associate
+a
+type
+with
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>.
+Although
+the
+same
+keyword
+is
+used
+in
+both
+places,
+the
+concept
+of
+an
+<em>
+object
+type
+</em>
+and
+a
+<em>
+value
+type
+</em>
+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>
+<div id="multiple-objects-for-a-single-property" class="section">
+<h3>
+<span class="secno">
+3.7
+</span>
+Multiple
+Objects
+for
+a
+Single
+Property
+</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.
+If
+a
+subject
+has
+multiple
+values
+for
+the
+same
+property,
+the
+author
+<em class="rfc2119" title="may">
+may
+</em>
+express
+each
+property
+as
+an
+<a class="tref internalDFN" title="array" href="#dfn-array">
+array
+</a>.
+</p>
+<p class="note">
+In
+JSON-LD,
+multiple
+objects
+on
+a
+property
+are
+not
+ordered.
+This
+is
+because
+graphs
+are
+inherently
+unordered
+data
+structures.
+To
+learn
+more
+about
+creating
+ordered
+collections
+in
+JSON-LD,
+see
+the
+section
+on
+<a href="#lists">
+Lists
+</a>.
+</p>
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}
+</pre>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<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>
+<div id="multiple-values-for-a-single-property" class="section">
+<h3>
+<span class="secno">
+3.8
+</span>
+Multiple
+Values
+for
+a
+Single
+Property
+</h3>
+<p>
+Multiple
+<a class="tref internalDFN" title="value" href="#dfn-value">
+value
+</a>
+s
+may
+also
+be
+expressed
+using
+the
+expanded
+form
+for
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+s:
+</p>
+<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>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<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>
+<div id="lists" class="section">
+<h3>
+<span class="secno">
+3.9
+</span>
+Lists
+</h3>
+<p>
+Because
+graphs
+do
+not
+describe
+ordering
+for
+links
+between
+nodes,
+in
+contrast
+to
+plain
+JSON,
+multi-valued
+properties
+in
+JSON-LD
+do
+not
+provide
+an
+ordering
+of
+the
+listed
+objects.
+For
+example,
+consider
+the
+following
+simple
+document:
+</p>
+ <pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}
+</pre>
+<p>
+This
+results
+in
+three
+triples
+being
+generated,
+each
+relating
+the
+subject
+to
+an
+individual
+object,
+with
+no
+inherent
+order.
+</p>
+<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>
+keyword
+as
+follows:
+</p>
+ <pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "foaf:nick": <span class="diff">{ "@list": [ "joe", "bob", "jaybee" ] }</span>,
+...
+}
+</pre>
+<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
+through
+alternate
+representations
+as
+described
+in
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+If
+every
+use
+of
+a
+given
+multi-valued
+property
+is
+a
+list,
+this
+may
+be
+abbreviated
+by
+adding
+a
+<code>
+@type
+</code>
+<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
+coercion
+</a>:
+</p>
+ <pre class="example">{
+ <span class="diff">"@context": {
+ ...
+ "nick": {
+ "@id": "http://xmlns.com/foaf/0.1/nick",
+ "@list": true
+ }
+}</span>,
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}
+</pre>
+<p>
+List
+coercion
+is
+specified
+within
+an
+expanded
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+definition
+using
+the
+<code>
+@list
+</code>
+key.
+The
+value
+of
+this
+key,
+if
+present,
+<em class="rfc2119" title="must">
+must
+</em>
+be
+<code>
+true
+</code>.
+This
+indicates
+that
+array
+values
+of
+keys
+coerced
+as
+<code>
+@list
+</code>
+are
+to
+be
+serialized
+as
+a
+<a href="#lists">
+List
+</a>.
+</p>
+</div>
+</div>
+<div id="advanced-concepts" class="section">
+<h2>
+<span class="secno">
+4.
+</span>
+Advanced
+Concepts
+</h2>
+<p>
+JSON-LD
+has
+a
+number
+of
+features
+that
+provide
+functionality
+above
+and
+beyond
+the
+core
+functionality
+described
+above.
+The
+following
+sections
+outline
+the
+features
+that
+are
+specific
+to
+JSON-LD.
+</p>
+<div id="prefixes" class="section">
+<h3>
+<span class="secno">
+4.1
+</span>
+Prefixes
+</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
+term
+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
+three
+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,
+the
+second
+is
+the
+serialized
+size
+of
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+if
+it
+is
+specified
+inline,
+the
+third
+is
+future-proofing
+embedded
+application
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+s
+that
+may
+not
+be
+easy
+to
+change
+after
+they
+are
+deployed.
+In
+order
+to
+address
+these
+issues,
+the
+concept
+of
+a
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+mechanism
+is
+introduced.
+</p>
+<p>
+A
+<dfn title="prefix" id="dfn-prefix">
+prefix
+</dfn>
+is
+a
+compact
+way
+of
+expressing
+a
+base
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+for
+a
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>.
+Generally,
+these
+prefixes
+are
+used
+by
+concatenating
+the
+<em>
+prefix
+</em>
+and
+a
+<em>
+suffix
+</em>,
+which
+is
+separated
+by
+a
+colon
+(
+<code>:
+</code>
+).
+The
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+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
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+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>
+To
+generate
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+out
+of
+a
+<code>
+prefix:suffix
+</code>
+construct,
+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
+used
+directly
+as
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>.
+If
+the
+prefix
+is
+an
+underscore
+(
+<code>
+_
+</code>
+),
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+remains
+unchanged.
+</p>
+<p>
+The
+ability
+to
+use
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>
+es
+reduces
+the
+need
+for
+developers
+to
+declare
+every
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+term
+that
+they
+intend
+to
+use
+in
+the
+JSON-LD
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+This
+reduces
+stand-alone
+JSON-LD
+document
+serialization
+size
+because
+every
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+term
+need
+not
+be
+declared
+in
+the
+embedded
+context.
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+Prefix
+</a>
+also
+reduces
+the
+cognitive
+load
+on
+the
+developer.
+It
+is
+far
+easier
+to
+remember
+<code>
+foaf:name
+</code>
+than
+it
+is
+to
+remember
+<code>
+http://xmlns.com/foaf/0.1/name
+</code>.
+The
+use
+of
+prefixes
+also
+ensures
+that
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+document
+does
+not
+have
+to
+be
+updated
+in
+lock-step
+with
+an
+externally
+defined
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>.
+Without
+prefixes,
+a
+developer
+would
+need
+to
+keep
+their
+application
+context
+terms
+in
+lock-step
+with
+an
+externally
+defined
+vocabulary.
+Rather,
+by
+just
+declaring
+the
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+prefix,
+one
+can
+use
+new
+terms
+as
+they're
+declared
+without
+having
+to
+update
+the
+application's
+JSON-LD
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+</p>
+<p>
+Consider
+the
+following
+example:
+</p>
+ <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>
+<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
+<code>
+prefix:suffix
+</code>
+notation.
+</p>
+<p>
+Prefixes,
+also
+known
+as
+CURIEs,
+are
+defined
+more
+formally
+in
+RDFa
+Core
+1.1,
+<cite>
+<a href="http://www.w3.org/TR/rdfa-core/#s_curies">
+Section
+6
+"CURIE
+Syntax
+Definition"
+</a>
+</cite>
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RDFA-CORE">
+RDFA-CORE
+</a>
+</cite>
+].
+JSON-LD
+does
+not
+support
+the
+square-bracketed
+CURIE
+syntax
+as
+the
+mechanism
+is
+not
+required
+to
+disambiguate
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+in
+a
+JSON-LD
+document
+like
+it
+is
+in
+HTML
+documents.
+</p>
+</div>
+<div id="external-contexts" class="section">
+<h3>
+<span class="secno">
+4.2
+</span>
+External
+Contexts
+</h3>
+<p>
+Authors
+may
+choose
+to
+declare
+JSON-LD
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+s
+in
+external
+documents
+to
+promote
+re-use
+of
+contexts
+as
+well
+as
+reduce
+the
+size
+of
+JSON-LD
+documents.
+</p>
+<p>
+In
+order
+to
+use
+an
+external
+context,
+an
+author
+<em class="rfc2119" title="may">
+may
+</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.
+The
+referenced
+document
+<em class="rfc2119" title="must">
+must
+</em>
+have
+a
+top-level
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+Object
+</a>.
+The
+value
+of
+any
+<code>
+@context
+</code>
+key
+within
+that
+object
+is
+substituted
+for
+the
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+within
+the
+referencing
+document
+to
+have
+the
+same
+effect
+as
+if
+the
+value
+were
+specified
+inline
+within
+the
+referencing
+document.
+</p>
+<p>
+The
+following
+example
+demonstrates
+the
+use
+of
+an
+external
+context:
+</p>
+<pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}
+</pre>
+<p>
+Authors
+may
+also
+import
+multiple
+contexts
+or
+a
+combination
+of
+external
+and
+local
+contexts
+by
+specifying
+a
+list
+of
+contexts:
+</p>
+<pre class="example">{
+ <span class="diff">"@context":
+ [
+ "http://json-ld.org/contexts/person",
+ { "foaf": "http://xmlns.com/foaf/0.1/" },
+ "http://json-ld.org/contexts/event",
+ ]</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+ <span class="diff">"celebrates":
+ {
+ "@type": "Event",
+ "description": "International Talk Like a Pirate Day",
+ "date": "R/2011-09-19"
+ }</span>
+}
+</pre>
+<p>
+Each
+context
+in
+a
+list
+will
+be
+evaluated
+in-order.
+Duplicate
+mappings
+among
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+s
+<em class="rfc2119" title="must">
+must
+</em>
+be
+overwritten
+on
+a
+last-defined-overrides
+basis.
+The
+context
+list
+<em class="rfc2119" title="must">
+must
+</em>
+contain
+either
+de-referenceable
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s
+or
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+Object
+</a>
+s
+that
+conform
+to
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+syntax
+as
+described
+in
+this
+document.
+</p>
+<p>
+An
+author
+may
+nest
+contexts
+within
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+object
+</a>
+s,
+with
+the
+more
+deeply
+nested
+contexts
+overriding
+the
+values
+in
+previously
+defined
+contexts:
+</p>
+<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",
+ ...
+ "details":
+ {
+ <span class="diff">"@context": { "name": "http://example.com/organization#name" },</span>
+ "<span class="diff">name</span>": "Acme, Ltd."
+ }
+}
+</pre>
+<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
+the
+JSON
+object
+has
+legacy
+applications
+using
+the
+structure
+of
+the
+object.
+</p>
+<p>
+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="prefix" href="#dfn-prefix">
+prefix
+</a>
+es
+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.
+It
+is
+also
+<em class="rfc2119" title="recommended">
+recommended
+</em>
+that
+a
+human-readable
+document
+encoded
+in
+HTML+RDFa
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-HTML-RDFA">
+HTML-RDFA
+</a>
+</cite>
+]
+or
+other
+Linked
+Data
+compatible
+format
+is
+served
+as
+well
+to
+explain
+the
+correct
+usage
+of
+the
+JSON-LD
+context
+document.
+</p>
+</div>
+<div id="default-language" class="section">
+<h3>
+<span class="secno">
+4.3
+</span>
+Default
+Language
+</h3>
+<p>
+JSON-LD
+allows
+a
+default
+value
+to
+use
+as
+the
+language
+for
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+s.
+It
+is
+commonly
+the
+case
+that
+documents
+are
+written
+using
+a
+single
+language.
+As
+described
+in
+<a href="string-internationalization">
+String
+Internationalization
+</a>,
+a
+language-tagged
+value
+<em class="rfc2119" title="may">
+may
+</em>
+be
+specified
+as
+follows:
+</p>
+<pre class="example">{
+...
+ "name":
+ {
+ "@value": "花澄",
+ "@language": "ja"
+ }
+...
+}
+</pre>
+<p>
+It
+is
+also
+possible
+to
+apply
+a
+particular
+language
+code
+to
+all
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+s
+by
+setting
+the
+<code>
+@language
+</code>
+key
+in
+the
+<code>
+@context
+</code>:
+</p>
+<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>
+<p>
+The
+example
+above
+would
+generate
+a
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+for
+<em>
+花澄
+</em>
+and
+<em>
+科学者
+</em>
+and
+associate
+the
+<code>
+ja
+</code>
+language
+code
+with
+each
+value.
+</p>
+<p>
+It
+is
+possible
+to
+override
+the
+default
+language
+by
+using
+the
+expanded
+form
+of
+a
+value:
+</p>
+<pre class="example">{
+ "@context:"
+ {
+ "@language": "ja"
+ },
+...
+ "name": "花澄"
+ "occupation": <span class="diff">
+ {
+ "@value": "Scientist",
+ "@language": "en"
+ }</span>
+...
+}
+</pre>
+<p>
+It
+is
+also
+possible
+to
+override
+the
+default
+language
+and
+specify
+a
+plain
+value
+by
+omitting
+the
+<code>
+@language
+</code>
+tag
+when
+expressing
+the
+expanded
+value:
+</p>
+<pre class="example">{
+ "@context:"
+ {
+ "@language": "ja"
+ },
+...
+ "name": "花澄"
+ "occupation": <span class="diff">
+ {
+ "@value": "Ninja"
+ }</span>
+...
+}
+</pre>
+<p>
+Object
+<a class="tref internalDFN" title="property" href="#dfn-property">
+properties
+</a>
+that
+use
+the
+expanded
+form
+are
+considered
+explicitly
+defined.
+The
+<code>
+@language
+</code>
+keyword,
+when
+used
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>,
+<em class="rfc2119" title="must">
+must
+</em>
+only
+be
+applied
+to
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+s.
+That
+is,
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">
+string
+value
+</a>
+s
+expressed
+in
+expanded
+form
+are
+not
+affected
+by
+the
+<code>
+@language
+</code>
+keyword,
+when
+it
+is
+used
+in
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>.
+</p>
+</div>
+<div id="expanded-term-definition" class="section">
+<h3>
+<span class="secno">
+4.4
+</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
+term
+to
+be
+specified
+(see
+<a href="#type-coerceion">
+Type
+Coercion
+</a>
+and
+<a href="#lists">
+Lists
+</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
+an
+object
+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="prefix" href="#dfn-prefix">
+prefix
+</a>:suffix
+value,
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+Type
+information
+may
+be
+specified
+</p>
+<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>
+<div id="automatic-typing" class="section">
+<h3>
+<span class="secno">
+4.5
+</span>
+Automatic
+Typing
+</h3>
+<p>
+Since
+JSON
+is
+capable
+of
+expressing
+typed
+information
+such
+as
+doubles,
+integers,
+and
+boolean
+values.
+As
+demonstrated
+below,
+JSON-LD
+utilizes
+that
+information
+to
+create
+<a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">
+typed
+value
+</a>
+s:
+</p>
+<pre class="example">{
+...
+ // The following two values are automatically converted to a type of xsd:double
+ // and both values are equivalent to each other.
+ "measure:cups": <span class="diff">5.3</span>,
+ "measure:cups": <span class="diff">5.3e0</span>,
+ // The following value is automatically converted to a type of xsd:double as well
+ "space:astronomicUnits": <span class="diff">6.5e73</span>,
+ // The following value is never converted to a language-native type
+ "measure:stones": <span class="diff">{ "@value": "4.8", "@type": "xsd:decimal" }</span>,
+ // This value is automatically converted to having a type of xsd:integer
+ "chem:protons": <span class="diff">12</span>,
+ // This value is automatically converted to having a type of xsd:boolean
+ "sensor:active": <span class="diff">true</span>,
+...
+}
+</pre>
+<p class="note">
+When
+dealing
+with
+a
+number
+of
+modern
+programming
+languages,
+including
+JavaScript
+ECMA-262,
+there
+is
+no
+distinction
+between
+<strong>
+xsd:decimal
+</strong>
+and
+<strong>
+xsd:double
+</strong>
+values.
+That
+is,
+the
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>
+<code>
+5.3
+</code>
+and
+the
+<a class="tref internalDFN" title="number" href="#dfn-number">
+number
+</a>
+<code>
+5.3e0
+</code>
+are
+treated
+as
+if
+they
+were
+the
+same.
+When
+converting
+from
+JSON-LD
+to
+a
+language-native
+format
+and
+back,
+type
+information
+is
+lost
+in
+a
+number
+of
+these
+languages.
+Thus,
+one
+could
+say
+that
+<code>
+5.3
+</code>
+is
+a
+<strong>
+xsd:decimal
+</strong>
+and
+<code>
+5.3e0
+</code>
+is
+an
+<strong>
+xsd:double
+</strong>
+in
+JSON-LD,
+but
+when
+both
+values
+are
+converted
+to
+a
+language-native
+format
+the
+type
+difference
+between
+the
+two
+is
+lost
+because
+the
+machine-level
+representation
+will
+almost
+always
+be
+a
+<strong>
+double
+</strong>.
+Implementers
+should
+be
+aware
+of
+this
+potential
+round-tripping
+issue
+between
+<strong>
+xsd:decimal
+</strong>
+and
+<strong>
+xsd:double
+</strong>.
+Specifically
+objects
+with
+a
+type
+of
+<strong>
+xsd:decimal
+</strong>
+<em class="rfc2119" title="must not">
+must
+not
+</em>
+be
+converted
+to
+a
+language
+native
+type.
+</p>
+</div>
+<div id="type-coercion" class="section">
+<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
+types
+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
+property
+types.
+Using
+type
+coercion,
+value
+representation
+is
+preserved
+without
+requiring
+the
+data
+type
+to
+be
+specified
+with
+each
+usage.
+</p>
+<p>
+Type
+coercion
+is
+specified
+within
+an
+<a href="#expanded-term-definition">
+expanded
+term
+definition
+</a>
+using
+the
+<code>
+@type
+</code>
+key.
+The
+values
+of
+this
+key
+represent
+type
+IRIs
+and
+<em class="rfc2119" title="must">
+must
+</em>
+take
+the
+form
+of
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>,
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>:suffix,
+absolute
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+or
+the
+keyword
+<code>
+@id
+</code>.
+Specifying
+<code>
+@id
+</code>
+indicates
+that
+within
+the
+body
+of
+a
+JSON-LD
+document,
+string
+values
+of
+keys
+coerced
+as
+<code>
+@id
+</code>
+are
+to
+be
+interpreted
+as
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+s.
+</p>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Terms
+</a>
+or
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefixes
+</a>
+used
+as
+the
+value
+of
+a
+<code>
+@type
+</code>
+key
+<em class="rfc2119" title="may">
+may
+</em>
+be
+defined
+within
+the
+same
+context.
+</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>
+<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", "@list": true }</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>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+Turtle:
+</p>
+<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>
+<div id="iri-expansion-within-a-context" class="section">
+<h3>
+<span class="secno">
+4.7
+</span>
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+Expansion
+Within
+a
+Context
+</h3>
+<p>
+To
+be
+consistent
+with
+JSON-LD,
+in
+general,
+anywhere
+an
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+is
+expected,
+normal
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+expansion
+rules
+apply
+(see
+<a href="#iris">
+IRIs
+</a>
+).
+Within
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+definition,
+this
+can
+mean
+that
+terms
+defined
+within
+a
+given
+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>
+<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>
+<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>
+<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>
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">
+Term
+</a>
+s
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+on
+the
+left-hand
+side
+of
+a
+definition.
+</p>
+<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>": {"@id": "foaf:age", "@type": xsd:integer"},
+ "<span class="diff">foaf:homepage</span>": <span class="diff">{ "@type": "@id" }</span>
+ },
+ ...
+}
+</pre>
+<p>
+Note
+that
+in
+this
+example,
+the
+prefixed
+form
+is
+used
+in
+two
+different
+ways.
+The
+first
+way,
+as
+shown
+with
+<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
+term
+(using
+short-form)
+as
+well
+as
+the
+<code>
+@type
+</code>
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>.
+The
+second
+way,
+only
+declares
+the
+<code>
+@type
+</code>
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>.
+In
+the
+second
+case,
+the
+JSON-LD
+processor
+will
+still
+derive
+the
+full
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+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>
+for
+<code>
+foaf:homepage
+</code>.
+</p>
+<p>
+Full
+IRIs
+<em class="rfc2119" title="may">
+may
+</em>
+also
+be
+used
+on
+the
+left-hand
+side
+of
+a
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>:
+</p>
+<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>
+<p>
+Note
+that
+in
+order
+for
+the
+full
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+to
+match
+above,
+the
+full
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+<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>
+<pre class="example">{
+ "@context":
+ {
+ <span class="diff">"term1": {"@id": "term2:foo"},
+ "term2": {"@id": "term1:bar"}</span>
+ },
+ ...
+}
+</pre>
+</div>
+<div id="embedding" class="section">
+<h3>
+<span class="secno">
+4.8
+</span>
+Embedding
+</h3>
+<p>
+Object
+<dfn title="embedding" id="dfn-embedding">
+embedding
+</dfn>
+is
+a
+JSON-LD
+feature
+that
+allows
+an
+author
+to
+use
+the
+definition
+of
+JSON-LD
+objects
+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="subject" href="#dfn-subject">
+subject
+</a>
+s.
+</p>
+<p>
+The
+example
+shows
+an
+two
+subjects
+related
+by
+a
+property
+from
+the
+first
+subject:
+</p>
+ <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>
+<p>
+An
+object
+definition,
+like
+the
+one
+used
+above,
+<em class="rfc2119" title="may">
+may
+</em>
+be
+used
+as
+a
+JSON
+value
+at
+any
+point
+in
+JSON-LD.
+</p>
+</div>
+<div id="identifying-unlabeled-nodes" class="section">
+<h3>
+<span class="secno">
+4.9
+</span>
+Identifying
+Unlabeled
+Nodes
+</h3>
+<p>
+At
+times,
+it
+becomes
+necessary
+to
+be
+able
+to
+express
+information
+without
+being
+able
+to
+specify
+the
+subject.
+Typically,
+this
+type
+of
+node
+is
+called
+an
+unlabeled
+node
+or
+a
+blank
+node.
+In
+JSON-LD,
+unlabeled
+node
+identifiers
+are
+automatically
+created
+if
+a
+subject
+is
+not
+specified
+using
+the
+<code>
+@id
+</code>
+keyword.
+However,
+authors
+may
+provide
+identifiers
+for
+unlabeled
+nodes
+by
+using
+the
+special
+<code>
+_
+</code>
+(underscore)
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">
+prefix
+</a>.
+This
+allows
+to
+reference
+the
+node
+locally
+within
+the
+document
+but
+not
+in
+an
+external
+document.
+</p>
+<pre class="example">{
+...
+ "@id": "<span class="diff">_:foo</span>",
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+set
+the
+subject
+to
+<code>
+_:foo
+</code>,
+which
+can
+then
+be
+used
+later
+on
+in
+the
+JSON-LD
+markup
+to
+refer
+back
+to
+the
+unlabeled
+node.
+This
+practice,
+however,
+is
+usually
+frowned
+upon
+when
+generating
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>.
+If
+a
+developer
+finds
+that
+they
+refer
+to
+the
+unlabeled
+node
+more
+than
+once,
+they
+should
+consider
+naming
+the
+node
+using
+a
+resolve-able
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>.
+</p>
+</div>
+<div id="aliasing-keywords" class="section">
+<h3>
+<span class="secno">
+4.10
+</span>
+Aliasing
+Keywords
+</h3>
+<p>
+JSON-LD
+allows
+all
+of
+the
+syntax
+keywords,
+except
+for
+<code>
+@context
+</code>,
+to
+be
+aliased.
+This
+feature
+allows
+more
+legacy
+JSON
+content
+to
+be
+supported
+by
+JSON-LD.
+It
+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>
+<pre class="example">{
+ "@context":
+ {
+ <span class="diff">"url": "@id"</span>,
+ <span class="diff">"a": "@type"</span>,
+ "name": "http://schema.org/name"
+ },
+ "url": "http://example.com/about#gregg",
+ "a": "http://schema.org/Person",
+ "name": "Gregg Kellogg"
+}
+</pre>
+<p>
+In
+the
+example
+above,
+the
+<code>
+@id
+</code>
+and
+<code>
+@type
+</code>
+keywords
+have
+been
+given
+the
+aliases
+<strong>
+url
+</strong>
+and
+<strong>
+a
+</strong>,
+respectively.
+</p>
+</div>
+</div>
+<div class="appendix informative section" id="markup-examples">
+<h2>
+<span class="secno">
+A.
+</span>
+Markup
+Examples
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<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
+[
+<cite>
+<a class="bibref" rel="biblioentry" 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
+such
+as
+Turtle,
+RDFa,
+Microformats,
+and
+Microdata.
+These
+sections
+are
+merely
+provided
+as
+proof
+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.
+Details
+of
+transforming
+JSON-LD
+into
+RDF
+are
+defined
+in
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">
+JSON-LD-API
+</a>
+</cite>
+].
+</p>
+<div id="turtle" class="section">
+<h3>
+<span class="secno">
+A.1
+</span>
+Turtle
+</h3>
+<p>
+The
+following
+are
+examples
+of
+representing
+<a class="tref internalDFN" title="rdf" href="#dfn-rdf">
+RDF
+</a>
+as
+expressed
+in
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-TURTLE">
+TURTLE
+</a>
+</cite>
+]
+into
+JSON-LD.
+</p>
+<div id="prefix-definitions" class="section">
+<h4>
+<span class="secno">
+A.1.1
+</span>
+Prefix
+definitions
+</h4>
+<p>
+The
+JSON-LD
+context
+has
+direct
+equivalents
+for
+the
+Turtle
+<code>
+@prefix
+</code>
+declaration:
+</p>
+<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>
+<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 class="note">
+<p>
+JSON-LD
+has
+no
+equivalent
+for
+the
+Turtle
+<code>
+@base
+</code>
+declaration.
+Authors
+could,
+of
+course,
+use
+a
+prefix
+definition
+to
+resolve
+relative
+IRIs.
+For
+example,
+an
+empty
+prefix
+could
+be
+used
+to
+get
+a
+similar
+effect
+to
+<code>
+@base
+</code>:
+</p>
+<pre class="example">{
+ "@context": {
+ <span class="diff">"": "http://manu.sporny.org/",</span>
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": <span class="diff">":i/public"</span>,
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": { "@id": <span class="diff">":" </span>}
+}
+</pre>
+</div>
+</div>
+<div id="embedding-1" class="section">
+<h4>
+<span class="secno">
+A.1.2
+</span>
+Embedding
+</h4>
+<p>
+Both
+Turtle
+and
+JSON-LD
+allow
+embedding
+of
+objects,
+although
+Turtle
+only
+allows
+embedding
+of
+objects
+which
+use
+unlabeled
+node
+identifiers.
+</p>
+</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>
+<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 id="lists-1" class="section">
+<h4>
+<span class="secno">
+A.1.3
+</span>
+Lists
+</h4>
+<p>
+Both
+JSON-LD
+and
+Turtle
+can
+represent
+sequential
+lists
+of
+values.
+</p>
+<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>
+<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", "jaybe" ] }
+}
+</pre>
+</div>
+</div>
+<div id="rdfa" class="section">
+<h3>
+<span class="secno">
+A.2
+</span>
+RDFa
+</h3>
+<p>
+The
+following
+example
+describes
+three
+people
+with
+their
+respective
+names
+and
+homepages.
+</p>
+<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>
+<p>
+An
+example
+JSON-LD
+implementation
+is
+described
+below,
+however,
+there
+are
+other
+ways
+to
+mark-up
+this
+information
+such
+that
+the
+<a class="tref internalDFN" title="context" href="#dfn-context">
+context
+</a>
+is
+not
+repeated.
+</p>
+<pre class="example">{
+ "@context": { "foaf": "http://xmlns.com/foaf/0.1/" },
+ "@id": [
+ {
+ "@id": "_:bnode1",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/bob/",
+ "foaf:name": "Bob"
+ },
+ {
+ "@id": "_:bnode2",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/eve/",
+ "foaf:name": "Eve"
+ },
+ {
+ "@id": "_:bnode3",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/manu/",
+ "foaf:name": "Manu"
+ }
+ ]
+}
+</pre>
+</div>
+<div id="microformats" class="section">
+<h3>
+<span class="secno">
+A.3
+</span>
+Microformats
+</h3>
+<p>
+The
+following
+example
+uses
+a
+simple
+Microformats
+hCard
+example
+to
+express
+how
+the
+Microformat
+is
+represented
+in
+JSON-LD.
+</p>
+<pre class="example"><div class="vcard">
+ <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</div>
+</pre>
+<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>
+<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"
+ },
+ "@id": "_:bnode1",
+ "@type": "vcard",
+ "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+}
+</pre>
+</div>
+<div id="microdata" class="section">
+<h3>
+<span class="secno">
+A.4
+</span>
+Microdata
+</h3>
+<p>
+The
+microdata
+example
+below
+expresses
+book
+information
+as
+a
+microdata
+Work
+item.
+</p>
+<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>
+<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>
+<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>
+</div>
+<div class="appendix section" id="linked-data">
+<h2>
+<span class="secno">
+B.
+</span>
+Linked
+Data
+</h2>
+<p>
+The
+following
+definition
+for
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+is
+the
+one
+that
+will
+be
+used
+for
+this
+specification.
+</p>
+<ol>
+<li>
+<dfn title="linked_data" id="dfn-linked_data">
+Linked
+Data
+</dfn>
+is
+a
+set
+of
+documents,
+each
+containing
+a
+representation
+of
+a
+linked
+data
+graph.
+</li>
+<li>
+A
+<dfn title="linked_data_graph" id="dfn-linked_data_graph">
+linked
+data
+graph
+</dfn>
+is
+an
+unordered
+labeled
+directed
+graph,
+where
+nodes
+are
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+s
+or
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+s,
+and
+edges
+are
+properties.
+</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" rel="biblioentry" 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>.
+</li>
+<li>
+An
+object
+<em class="rfc2119" title="may">
+may
+</em>
+be
+a
+<a class="tref internalDFN" title="subject" href="#dfn-subject">
+subject
+</a>
+and
+<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
+an
+edge
+of
+the
+<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
+labeled
+with
+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="object" href="#dfn-object">
+object
+</a>
+or
+<a class="tref internalDFN" title="property" href="#dfn-property">
+property
+</a>.
+</li>
+<li>
+A
+<dfn title="value" id="dfn-value">
+value
+</dfn>
+is
+an
+<a class="tref internalDFN" title="object" href="#dfn-object">
+object
+</a>
+with
+a
+label
+that
+is
+not
+an
+<a class="tref internalDFN" title="iri" href="#dfn-iri">
+<abbr title="Internationalized Resource Identifier">
+IRI
+</abbr>
+</a>
+</li>
+</ol>
+<p>
+Note
+that
+the
+definition
+for
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>
+above
+is
+silent
+on
+the
+topic
+of
+unlabeled
+nodes.
+Unlabeled
+nodes
+are
+not
+considered
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">
+Linked
+Data
+</a>.
+However,
+this
+specification
+allows
+for
+the
+expression
+of
+unlabled
+nodes,
+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>
+</div>
+<div class="appendix informative section" id="mashing-up-vocabularies">
+<h2>
+<span class="secno">
+C.
+</span>
+Mashing
+Up
+Vocabularies
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+Developers
+benefit
+by
+being
+able
+to
+mash
+other
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+into
+their
+JSON-LD
+markup.
+There
+are
+over
+200
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+that
+are
+available
+for
+use
+on
+the
+Web
+today.
+Some
+of
+these
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+include:
+</p>
+<ul>
+<li>
+RDF
+-
+for
+describing
+information
+about
+objects
+and
+concepts
+on
+the
+Web.
+</li>
+<li>
+RDFS
+-
+for
+expressing
+things
+like
+labels
+and
+comments.
+</li>
+<li>
+XSD
+-
+for
+specifying
+basic
+types
+like
+strings,
+integers,
+dates
+and
+times.
+</li>
+<li>
+Dublin
+Core
+-
+for
+describing
+creative
+works.
+</li>
+<li>
+FOAF
+-
+for
+describing
+social
+networks.
+</li>
+<li>
+Calendar
+-
+for
+specifying
+events.
+</li>
+<li>
+SIOC
+-
+for
+describing
+discussions
+on
+blogs
+and
+websites.
+</li>
+<li>
+CCrel
+-
+for
+describing
+Creative
+Commons
+and
+other
+types
+of
+licenses.
+</li>
+<li>
+GEO
+-
+for
+describing
+geographic
+location.
+</li>
+<li>
+VCard
+-
+for
+describing
+organizations
+and
+people.
+</li>
+<li>
+DOAP
+-
+for
+describing
+projects.
+</li>
+</ul>
+<p>
+You
+can
+use
+these
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabularies
+</a>
+in
+combination,
+like
+so:
+</p>
+<pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",<span class="diff">
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#"</span>
+ },
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": "http://manu.sporny.org/",<span class="diff">
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
+ "rdfs:comment": "Likes puppies, unicorns and rainbows."</span>
+}
+</pre>
+<p>
+Developers
+can
+also
+specify
+their
+own
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">
+vocabulary
+</a>
+documents
+by
+modifying
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+in-line
+using
+the
+<code>
+@context
+</code>
+keyword,
+like
+so:
+</p>
+<pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
+ <span class="diff">"myvocab": "http://example.org/myvocab#"</span>
+ },
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": "http://manu.sporny.org/",
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
+ "rdfs:comment": "Likes puppies, unicorns and rainbows."
+ <span class="diff">"myvocab:personality": "friendly"</span>
+}
+</pre>
+</div>
+<div class="appendix informative section" id="iana-considerations">
+<h2>
+<span class="secno">
+D.
+</span>
+IANA
+Considerations
+</h2>
+<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
+W3C
+Recommendation.
+</p>
+<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.
+Valid
+values
+include;
+<code>
+compacted
+</code>,
+<code>
+expanded
+</code>,
+and
+<code>
+normalized
+</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
+for
+an
+HTTP
+client,
+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/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,
+Dave
+Longley
+</dd>
+<dt>
+Change
+controller:
+</dt>
+<dd>
+W3C
+</dd>
+</dl>
+</div>
+<div class="appendix informative section" id="acknowledgements">
+<h2>
+<span class="secno">
+E.
+</span>
+Acknowledgements
+</h2>
+<p>
+<em>
+This
+section
+is
+non-normative.
+</em>
+</p>
+<p>
+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,
+Dave
+Longley,
+Dave
+Lehn
+and
+Mike
+Johnson
+who
+reviewed,
+provided
+feedback,
+and
+performed
+several
+implementations
+of
+the
+specification,
+and
+Ian
+Davis,
+who
+created
+RDF/JSON.
+Thanks
+also
+to
+Nathan
+Rixham,
+Bradley
+P.
+Allen,
+Kingsley
+Idehen,
+Glenn
+McDonald,
+Alexandre
+Passant,
+Danny
+Ayers,
+Ted
+Thibodeau
+Jr.,
+Olivier
+Grisel,
+Niklas
+Lindström,
+Markus
+Lanthaler,
+and
+Richard
+Cyganiak
+for
+their
+input
+on
+the
+specification.
+</p>
+</div>
+<div id="references" class="appendix section">
+<h2>
+<span class="secno">
+F.
+</span>
+References
+</h2>
+<div id="normative-references" class="section">
+<h3>
+<span class="secno">
+F.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/rfc/bcp/bcp47.txt">
+<cite>
+Tags
+for
+Identifying
+Languages
+</cite>
+</a>
+September
+2009.
+IETF
+Best
+Current
+Practice.
+URL:
+<a href="http://tools.ietf.org/rfc/bcp/bcp47.txt">
+http://tools.ietf.org/rfc/bcp/bcp47.txt
+</a>
+</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-WEBIDL">
+[WEBIDL]
+</dt>
+<dd>
+Cameron
+McCormack.
+<a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/">
+<cite>
+Web
+IDL.
+</cite>
+</a>
+27
+September
+2011.
+W3C
+Working
+Draft.
+(Work
+in
+progress.)
+URL:
+<a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/">
+http://www.w3.org/TR/2011/WD-WebIDL-20110927/
+</a>
+</dd>
+</dl>
+</div>
+<div id="informative-references" class="section">
+<h3>
+<span class="secno">
+F.2
+</span>
+Informative
+references
+</h3>
+<dl class="bibliography">
+<dt id="bib-ECMA-262">
+[ECMA-262]
+</dt>
+<dd>
+<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
+<cite>
+ECMAScript
+Language
+Specification.
+</cite>
+</a>
+December
+1999.
+URL:
+<a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">
+http://www.ecma-international.org/publications/standards/Ecma-262.htm
+</a>
+</dd>
+<dt id="bib-HTML-RDFA">
+[HTML-RDFA]
+</dt>
+<dd>
+Manu
+Sporny;
+et
+al.
+<a href="http://www.w3.org/TR/rdfa-in-html/">
+<cite>
+HTML+RDFa
+</cite>
+</a>
+04
+March
+2010.
+W3C
+Working
+Draft.
+URL:
+<a href="http://www.w3.org/TR/rdfa-in-html/">
+http://www.w3.org/TR/rdfa-in-html/
+</a>
+</dd>
+<dt id="bib-JSON-LD-API">
+[JSON-LD-API]
+</dt>
+<dd>
+Manu
+Sporny,
+Gregg
+Kellogg,
+Dave
+Longley,
+Eds.
+<cite>
+<a href="http://json-ld.org/spec/latest/json-ld-api/">
+JSON-LD
+API
+</a>
+</cite>
+Latest.
+W3C
+Editor's
+Draft.
+URL:
+<a href="http://json-ld.org/spec/latest/json-ld-api/">
+http://json-ld.org/spec/latest/json-ld-api/
+</a>
+</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-RDFA-CORE">
+[RDFA-CORE]
+</dt>
+<dd>
+Shane
+McCarron;
+et
+al.
+<a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215">
+<cite>
+RDFa
+Core
+1.1:
+Syntax
+and
+processing
+rules
+for
+embedding
+RDF
+through
+attributes.
+</cite>
+</a>
+15
+December
+2011.
+W3C
+Working
+Draft.
+URL:
+<a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215">
+http://www.w3.org/TR/2011/WD-rdfa-core-20111215
+</a>
+</dd>
+<dt id="bib-TURTLE">
+[TURTLE]
+</dt>
+<dd>
+David
+Beckett,
+Tim
+Berners-Lee.
+<a href="http://www.w3.org/TeamSubmission/turtle/">
+<cite>
+Turtle:
+Terse
+RDF
+Triple
+Language.
+</cite>
+</a>
+January
+2008.
+W3C
+Team
+Submission.
+URL:
+<a href="http://www.w3.org/TeamSubmission/turtle/">
+http://www.w3.org/TeamSubmission/turtle/
+</a>
+</dd>
+<dt id="bib-XML-NAMES">
+[XML-NAMES]
+</dt>
+<dd>
+Richard
+Tobin;
+et
+al.
+<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">
+<cite>
+Namespaces
+in
+XML
+1.0
+(Third
+Edition).
+</cite>
+</a>
+8
+December
+2009.
+W3C
+Recommendation.
+URL:
+<a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">
+http://www.w3.org/TR/2009/REC-xml-names-20091208/
+</a>
+</dd>
+</dl>
+</div>
+</div>
+</body>
+</html>
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/ED/json-ld-syntax/20120122/index.html Sun Jan 22 14:59:39 2012 -0500
@@ -0,0 +1,2411 @@
+<?xml version='1.0' encoding='UTF-8'?>
+<!DOCTYPE html PUBLIC '-//W3C//DTD XHTML 1.0 Transitional//EN' 'http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd'>
+<html dir="ltr" xmlns="http://www.w3.org/1999/xhtml">
+<head>
+<title>JSON-LD Syntax 1.0</title>
+<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
+
+<!--
+ === NOTA BENE ===
+ For the three scripts below, if your spec resides on dev.w3 you can check them
+ out in the same tree and use relative links so that they'll work offline,
+ -->
+
+
+
+<style>
+.diff { font-weight:bold; color:#0a3; }
+ol.algorithm.update { margin-left: 2em; }
+ol.algorithm.update>li { list-style-type: none; }
+ol.algorithm.update>li>span.list-number {
+ display:block;
+ float: left;
+ margin-left: -3.5em;
+}
+</style>
+<style type="text/css">
+/*****************************************************************
+ * ReSpec CSS
+ * Robin Berjon (robin at berjon dot com)
+ * v0.05 - 2009-07-31
+ *****************************************************************/
+
+
+/* --- INLINES --- */
+em.rfc2119 {
+ text-transform: lowercase;
+ font-variant: small-caps;
+ font-style: normal;
+ color: #900;
+}
+
+h1 acronym, h2 acronym, h3 acronym, h4 acronym, h5 acronym, h6 acronym, a acronym,
+h1 abbr, h2 abbr, h3 abbr, h4 abbr, h5 abbr, h6 abbr, a abbr {
+ border: none;
+}
+
+dfn {
+ font-weight: bold;
+}
+
+a.internalDFN {
+ color: inherit;
+ border-bottom: 1px solid #99c;
+ text-decoration: none;
+}
+
+a.externalDFN {
+ color: inherit;
+ border-bottom: 1px dotted #ccc;
+ text-decoration: none;
+}
+
+a.bibref {
+ text-decoration: none;
+}
+
+code {
+ color: #ff4500;
+}
+
+
+/* --- WEB IDL --- */
+pre.idl {
+ border-top: 1px solid #90b8de;
+ border-bottom: 1px solid #90b8de;
+ padding: 1em;
+ line-height: 120%;
+}
+
+pre.idl::before {
+ content: "WebIDL";
+ display: block;
+ width: 150px;
+ background: #90b8de;
+ color: #fff;
+ font-family: initial;
+ padding: 3px;
+ font-weight: bold;
+ margin: -1em 0 1em -1em;
+}
+
+.idlType {
+ color: #ff4500;
+ font-weight: bold;
+ text-decoration: none;
+}
+
+/*.idlModule*/
+/*.idlModuleID*/
+/*.idlInterface*/
+.idlInterfaceID, .idlDictionaryID {
+ font-weight: bold;
+ color: #005a9c;
+}
+
+.idlSuperclass {
+ font-style: italic;
+ color: #005a9c;
+}
+
+/*.idlAttribute*/
+.idlAttrType, .idlFieldType, .idlMemberType {
+ color: #005a9c;
+}
+.idlAttrName, .idlFieldName, .idlMemberName {
+ color: #ff4500;
+}
+.idlAttrName a, .idlFieldName a, .idlMemberName a {
+ color: #ff4500;
+ border-bottom: 1px dotted #ff4500;
+ text-decoration: none;
+}
+
+/*.idlMethod*/
+.idlMethType {
+ color: #005a9c;
+}
+.idlMethName {
+ color: #ff4500;
+}
+.idlMethName a {
+ color: #ff4500;
+ border-bottom: 1px dotted #ff4500;
+ text-decoration: none;
+}
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+/*.idlParam*/
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+ color: #005a9c;
+}
+.idlParamName {
+ font-style: italic;
+}
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+ color: #666;
+}
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+/*.idlConst*/
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+}
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+}
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+ font-weight: bold;
+ color: #c00;
+}
+
+.idlTypedefID, .idlTypedefType {
+ color: #005a9c;
+}
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+ color: #c00;
+ font-weight: normal;
+}
+
+.excName a {
+ font-family: monospace;
+}
+
+.idlRaises a.idlType, .excName a.idlType {
+ border-bottom: 1px dotted #c00;
+}
+
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+ width: 45px;
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+}
+.excGetSetTrue, .prmNullTrue, .prmOptTrue { color: #0c0; }
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+.idlImplements a {
+ font-weight: bold;
+}
+
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+}
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+ font-weight: normal;
+}
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+ font-weight: bold;
+ color: #000;
+ font-family: monospace;
+}
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+ font-style: italic;
+}
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+}
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+}
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+}
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+}
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+ border-collapse: collapse;
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+}
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+}
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+a .secno {
+ color: #000;
+}
+
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+}
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+ color: #fff;
+ padding: 3px 5px;
+ text-align: left;
+}
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+ color: inherit;
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+}
+
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+}
+
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+}
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+/* --- DL --- */
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+}
+
+.section dd > p:last-child {
+ margin-bottom: 0;
+}
+
+.section dd {
+ margin-bottom: 1em;
+}
+
+.section dl.attrs dd, .section dl.eldef dd {
+ margin-bottom: 0;
+}
+
+/* --- EXAMPLES --- */
+pre.example {
+ border-top: 1px solid #ff4500;
+ border-bottom: 1px solid #ff4500;
+ padding: 1em;
+ margin-top: 1em;
+}
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+pre.example::before {
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+ display: block;
+ width: 150px;
+ background: #ff4500;
+ color: #fff;
+ font-family: initial;
+ padding: 3px;
+ font-weight: bold;
+ margin: -1em 0 1em -1em;
+}
+
+/* --- EDITORIAL NOTES --- */
+.issue {
+ padding: 1em;
+ margin: 1em 0em 0em;
+ border: 1px solid #f00;
+ background: #ffc;
+}
+
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+
+<body style="display: inherit; "><div class="head"><p></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="unofficial-draft-22-january-2012">Unofficial Draft 22 January 2012</h2><dl><dt>Editors:</dt><dd><a href="http://manu.sporny.org/">Manu Sporny</a>, <a href="http://digitalbazaar.com/">Digital Bazaar</a></dd>
+<dd><a href="http://greggkellogg.net/">Gregg Kellogg</a>, <a href="http://kellogg-assoc.com/">Kellogg Associates</a></dd>
+<dt>Authors:</dt><dd><a href="http://digitalbazaar.com/">Manu Sporny</a>, <a href="http://digitalbazaar.com/">Digital Bazaar</a></dd>
+<dd><a href="http://digitalbazaar.com/">Dave Longley</a>, <a href="http://digitalbazaar.com/">Digital Bazaar</a></dd>
+<dd><a href="http://greggkellogg.net/">Gregg Kellogg</a>, <a href="http://kellogg-assoc.com/">Kellogg Associates</a></dd>
+<dd><a href="http://www.markus-lanthaler.com/">Markus Lanthaler</a>, <a href="http://www.tugraz.at/">Graz University of Technology</a></dd>
+<dd><a href="http://webbackplane.com/">Mark Birbeck</a>, <a href="http://webbackplane.com/">Backplane Ltd.</a></dd>
+</dl><p>This document is also available in this non-normative format: <a href="diff-20120112.html">diff to previous version</a>.</p><p class="copyright">This document is licensed under a <a class="subfoot" href="http://creativecommons.org/licenses/by/3.0/" rel="license">Creative Commons Attribution 3.0 License</a>.</p><hr /></div>
+<div id="abstract" class="introductory section"><h2>Abstract</h2>
+<p>
+JSON [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC4627">RFC4627</a></cite>] 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>
+</div><div id="sotd" class="introductory section"><h2>Status of This Document</h2><p>This document is merely a public working draft of a potential specification. It has no official standing of any kind and does not represent the support or consensus of any standards organisation.</p>
+<p>This document is an experimental work in progress.</p>
+
+<!-- <p>
+This document has been reviewed by W3C Members, by software
+developers, and by other W3C groups and interested parties, and is
+endorsed by the Director as a W3C Recommendation. It is a stable
+document and may be used as reference material or cited from another
+document. W3C's role in making the Recommendation is to draw attention
+to the specification and to promote its widespread deployment. This
+enhances the functionality and interoperability of the Web.
+</p> -->
+
+</div><div id="toc" class="section"><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><li class="tocline"><a href="#syntax-tokens-and-keywords" class="tocxref"><span class="secno">1.2 </span>Syntax Tokens and Keywords</a></li><li class="tocline"><a href="#contributing" class="tocxref"><span class="secno">1.3 </span>Contributing</a></li></ul></li><li class="tocline"><a href="#design" class="tocxref"><span class="secno">2. </span>Design</a><ul class="toc"><li class="tocline"><a href="#goals-and-rationale" class="tocxref"><span class="secno">2.1 </span>Goals and Rationale</a></li><li class="tocline"><a href="#linking-data" class="tocxref"><span class="secno">2.2 </span>Linking Data</a><ul class="toc"><li class="tocline"><a href="#the-context" class="tocxref"><span class="secno">2.2.1 </span>The Context</a></li><li class="tocline"><a href="#from-json-to-json-ld" class="tocxref"><span class="secno">2.2.2 </span>From JSON to JSON-LD</a></li></ul></li></ul></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="#iris" class="tocxref"><span class="secno">3.1 </span>IRIs</a></li><li class="tocline"><a href="#identifying-the-subject" class="tocxref"><span class="secno">3.2 </span>Identifying the Subject</a></li><li class="tocline"><a href="#specifying-the-type" class="tocxref"><span class="secno">3.3 </span>Specifying the Type</a></li><li class="tocline"><a href="#strings" class="tocxref"><span class="secno">3.4 </span>Strings</a></li><li class="tocline"><a href="#string-internationalization" class="tocxref"><span class="secno">3.5 </span>String Internationalization</a></li><li class="tocline"><a href="#typed-values" class="tocxref"><span class="secno">3.6 </span>Typed Values</a></li><li class="tocline"><a href="#multiple-objects-for-a-single-property" class="tocxref"><span class="secno">3.7 </span>Multiple Objects for a Single Property</a></li><li class="tocline"><a href="#multiple-values-for-a-single-property" class="tocxref"><span class="secno">3.8 </span>Multiple Values for a Single Property</a></li><li class="tocline"><a href="#lists" class="tocxref"><span class="secno">3.9 </span>Lists</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="#prefixes" class="tocxref"><span class="secno">4.1 </span>Prefixes</a></li><li class="tocline"><a href="#external-contexts" class="tocxref"><span class="secno">4.2 </span>External Contexts</a></li><li class="tocline"><a href="#default-language" class="tocxref"><span class="secno">4.3 </span>Default Language</a></li><li class="tocline"><a href="#expanded-term-definition" class="tocxref"><span class="secno">4.4 </span>Expanded Term Definition</a></li><li class="tocline"><a href="#automatic-typing" class="tocxref"><span class="secno">4.5 </span>Automatic Typing</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="#iri-expansion-within-a-context" class="tocxref"><span class="secno">4.7 </span><abbr title="Internationalized Resource Identifier">IRI</abbr> Expansion Within a Context</a></li><li class="tocline"><a href="#embedding" class="tocxref"><span class="secno">4.8 </span>Embedding</a></li><li class="tocline"><a href="#identifying-unlabeled-nodes" class="tocxref"><span class="secno">4.9 </span>Identifying Unlabeled Nodes</a></li><li class="tocline"><a href="#aliasing-keywords" class="tocxref"><span class="secno">4.10 </span>Aliasing Keywords</a></li></ul></li><li class="tocline"><a href="#markup-examples" class="tocxref"><span class="secno">A. </span>Markup Examples</a><ul class="toc"><li class="tocline"><a href="#turtle" class="tocxref"><span class="secno">A.1 </span>Turtle</a><ul class="toc"><li class="tocline"><a href="#prefix-definitions" class="tocxref"><span class="secno">A.1.1 </span>Prefix definitions</a></li><li class="tocline"><a href="#embedding-1" class="tocxref"><span class="secno">A.1.2 </span>Embedding</a></li><li class="tocline"><a href="#lists-1" class="tocxref"><span class="secno">A.1.3 </span>Lists</a></li></ul></li><li class="tocline"><a href="#rdfa" class="tocxref"><span class="secno">A.2 </span>RDFa</a></li><li class="tocline"><a href="#microformats" class="tocxref"><span class="secno">A.3 </span>Microformats</a></li><li class="tocline"><a href="#microdata" class="tocxref"><span class="secno">A.4 </span>Microdata</a></li></ul></li><li class="tocline"><a href="#linked-data" class="tocxref"><span class="secno">B. </span>Linked Data</a></li><li class="tocline"><a href="#mashing-up-vocabularies" class="tocxref"><span class="secno">C. </span>Mashing Up Vocabularies</a></li><li class="tocline"><a href="#iana-considerations" class="tocxref"><span class="secno">D. </span>IANA Considerations</a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno">E. </span>Acknowledgements</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">F. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">F.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">F.2 </span>Informative references</a></li></ul></li></ul></div>
+
+
+
+<div class="informative section" 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" rel="biblioentry" 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 graph of interlinked data across
+different
+documents or Web sites. Data entities are described using <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s,
+which are typically dereferencable and thus may be used to find more
+information about an entity, creating a "Web of Knowledge". JSON-LD is intended to be a simple
+publishing method for expressing not only Linked Data in JSON, but also for adding
+semantics to existing JSON.
+</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 interoperable 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 with
+added semantics. Finally, the format is intended to be easy to parse, efficient
+to generate, and only requires a very small memory footprint in order to operate.
+</p>
+
+<div id="how-to-read-this-document" class="section">
+<h3><span class="secno">1.1 </span>How to Read this Document</h3>
+
+<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 way that is
+ cross-language compatible via 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" rel="biblioentry" 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" rel="biblioentry" href="#bib-RFC4627">RFC4627</a></cite>]. To understand the API and how it is
+intended to operate in a programming environment, it is useful to have working
+knowledge of the JavaScript programming language [<cite><a class="bibref" rel="biblioentry" href="#bib-ECMA-262">ECMA-262</a></cite>] and
+WebIDL [<cite><a class="bibref" rel="biblioentry" href="#bib-WEBIDL">WEBIDL</a></cite>].</p>
+
+<p>
+ JSON [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC4627">RFC4627</a></cite>] defines several terms which are used throughout this document:
+ </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 name/value pairs (or members). A name is a <a class="tref internalDFN" title="string" href="#dfn-string">string</a>. 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 <em class="rfc2119" title="should">should</em> be unique.
+ </dd>
+ <dt><dfn title="array" id="dfn-array">array</dfn></dt>
+ <dd>
+ An array is an ordered collection of values. An array structure is represented as square brackets surrounding zero or more values (or elements). Elements are separated by commas. Within JSON-LD, array order is not preserved by default, unless
+ specific markup is provided (see <a href="#lists">Lists</a>). This is because the basic data model of JSON-LD
+ is a <a class="tref internalDFN" title="linked_data_graph" href="#dfn-linked_data_graph">linked data graph</a>, which is inherently unordered.
+ </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. A
+ character is represented as a single character string.
+ </dd>
+ <dt><dfn title="number" id="dfn-number">number</dfn></dt>
+ <dd>
+ A number is 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 use of the <em>null</em> value is undefined within JSON-LD.
+ </dd>
+ </dl>
+<p></p>
+
+</div>
+
+<div id="syntax-tokens-and-keywords" class="section">
+ <h3><span class="secno">1.2 </span>Syntax Tokens and Keywords</h3>
+
+ <p>JSON-LD specifies a number of syntax tokens and keywords that are using
+ in all algorithms described in this section:</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 express specific identifiers in a compact manner. The
+ <code>@context</code> keyword is described in detail in the section titled
+ <a href="#the-context">The Context</a>.</dd>
+ <dt><code>@id</code></dt>
+ <dd>Used to uniquely identify things that are being described in the document.
+ This keyword is described in the section titled
+ <a href="#identifying-the-subject">Identifying the Subject</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 the sections titled
+ <a href="#string-internationalization">String Internationalization</a> and
+ <a href="#typed-values">Typed Values</a>.</dd>
+ <dt><code>@language</code></dt>
+ <dd>Used to specify the native language for a particular value.
+ This keyword is described in the section titled
+ <a href="#string-internationalization">String Internationalization</a>.</dd>
+ <dt><code>@type</code></dt>
+ <dd>Used to set the data type of a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</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">Typed Values</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="#lists">Lists</a>.</dd>
+ <dt><code>:</code></dt>
+ <dd>The separator for JSON keys and values that use the
+ <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> mechanism.</dd>
+ </dl>
+</div>
+
+<div id="contributing" class="section">
+<h3><span class="secno">1.3 </span>Contributing</h3>
+
+<p>There are a number of ways that one may participate in the development of
+this specification:</p>
+
+<ul>
+<li>Technical discussion typically occurs on the public 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 teleconferences</a> are held
+every week on Tuesdays at 1500 UTC.
+</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>.</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>
+
+</div>
+
+</div>
+
+<div class="informative section" id="design">
+
+<!-- OddPage -->
+<h2><span class="secno">2. </span>Design</h2><p><em>This section is non-normative.</em></p>
+
+<p>The following section outlines the design goals and rationale behind the
+JSON-LD markup language.
+</p>
+
+<div id="goals-and-rationale" class="section">
+<h3><span class="secno">2.1 </span>Goals and Rationale</h3>
+
+<p>
+A number of design considerations were explored during the creation of this
+markup language:
+</p>
+
+<dl>
+ <dt>Simplicity</dt>
+ <dd>Developers need only know JSON and two keywords (<code>@context</code>
+ and <code>@id</code>) to use the basic functionality in JSON-LD. No extra
+ processors or software libraries are necessary to use JSON-LD in its most
+ basic form. The language attempts to ensure that developers have an easy
+ learning curve.</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 simply 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 provides a mechanism 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 esoteric markup, we chose not to support the use case
+ and support a simplified syntax instead. So, while Zero Edits is a 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>
+</dl>
+</div>
+
+<div id="linking-data" class="section">
+<h3><span class="secno">2.2 </span>Linking Data</h3>
+
+<p>
+An Internationalized Resource Identifier
+(<dfn title="iri" id="dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></dfn>),
+as described in [<cite><a class="bibref" rel="biblioentry" href="#bib-RFC3987">RFC3987</a></cite>], is a mechanism for representing unique
+identifiers on the web. In <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>, an <abbr title="Internationalized Resource Identifier">IRI</abbr> is commonly
+used for expressing a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a>, a <a class="tref internalDFN" title="property" href="#dfn-property">property</a> or an
+<a class="tref internalDFN" title="object" href="#dfn-object">object</a>.
+</p>
+
+<p>JSON-LD defines a mechanism to map JSON terms, i.e., keys and values, to IRIs. 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>. There are a few techniques that can ensure
+that developers will generate good Linked Data for the Web. JSON-LD
+formalizes those techniques.
+</p>
+
+<p>We will be using the following JSON markup as the example for the
+rest of this section:
+</p>
+
+<pre class="example">{
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<div id="the-context" class="section">
+<h4><span class="secno">2.2.1 </span>The Context</h4>
+
+<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., keys 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 <em class="rfc2119" title="may">may</em> be expanded to an
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>. A <a class="tref internalDFN" title="term" href="#dfn-term">term</a> <em class="rfc2119" title="must">must</em> have the lexical form of <cite><a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/#NT-NCName">NCName</a></cite> (see [<cite><a class="bibref" rel="biblioentry" href="#bib-XML-NAMES">XML-NAMES</a></cite>]), or
+ be an empty string.</p>
+<p>The Web uses IRIs 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 <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> terms. 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 name/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 absolute
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or, 2) an <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> containing an
+ <code>@id</code>, <code>@type</code>, or <code>@list</code> keyword.
+</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>
+
+<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>
+
+<p>This context document can then be used in an JSON-LD document by adding a
+single line. The JSON markup as shown in the previous section could be changed
+as follows to link to the context document:</p>
+
+<pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person",</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<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 IRIs.
+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>
+
+<p>Contexts may 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>
+
+<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>
+
+<p>Contexts <em class="rfc2119" title="may">may</em> be used at any time a <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a> is defined.
+ A <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</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 array-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>
+
+<p>
+ The set of contexts defined within a specific <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON Object</a> are
+ referred to as <dfn title="local_context" id="dfn-local_context">local context</dfn>s. 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>
+
+<pre class="example">{
+ <span class="diff">"@context": [
+ "http://json-ld.org/contexts/person",
+ {
+ "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>
+
+<p>
+ JSON-LD uses a special type of machine-readable document called a
+ <dfn title="vocabulary" id="dfn-vocabulary">vocabulary</dfn> to define <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s that are then used
+ to describe concepts and "things" in the world.
+ Typically, these <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> documents have <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>es
+ associated with them and contain a number of <a class="tref internalDFN" title="term" href="#dfn-term">term</a> declarations.
+ <a class="tref internalDFN" title="prefix" href="#dfn-prefix">Prefix</a>es are helpful when a developer
+ wants to mix multiple <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a> together in a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>, but
+ does not want to go to the trouble of defining every single term in every
+ single vocabulary. Some Web Vocabularies may have dozens of terms defined.
+ If a developer wants to use 3-4 different <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a>, the number of terms
+ that would have to be declared in a single <a class="tref internalDFN" title="context" href="#dfn-context">context</a> could become
+ quite large. To reduce the number of different terms that must be defined,
+ JSON-LD also allows prefixes to be used to compact IRIs.
+</p>
+
+<p>For example, the <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> <code>http://xmlns.com/foaf/0.1/</code>
+specifies a <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> which may be represented using the
+<code>foaf</code> <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>. The <code>foaf</code> vocabulary
+contains a term called <strong>name</strong>. If you join the
+<code>foaf</code> <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> with the <strong>name</strong> suffix,
+you can build a compact <abbr title="Internationalized Resource Identifier">IRI</abbr> that will expand out into an absolute <abbr title="Internationalized Resource Identifier">IRI</abbr> for the
+<code>http://xmlns.com/foaf/0.1/name</code> <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> term.
+That is, the compact <abbr title="Internationalized Resource Identifier">IRI</abbr> (or short-form), is <code>foaf:name</code> and the
+expanded-form is <code>http://xmlns.com/foaf/0.1/name</code>. This vocabulary
+term is used to specify a person's name.
+</p>
+
+<p>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. Much like 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. IRIs provide a way to ensure that these terms
+are unambiguous.
+</p>
+
+<p>The <a class="tref internalDFN" title="context" href="#dfn-context">context</a> provides a collection of <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> <a class="tref internalDFN" title="term" href="#dfn-term">term</a>s and
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>es that can be used to expand JSON keys and values into
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s.</p>
+
+<p class="note">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 one-pass processors.</p>
+
+</div>
+
+<div id="from-json-to-json-ld" class="section">
+<h4><span class="secno">2.2.2 </span>From JSON to JSON-LD</h4>
+
+<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 JSON objects, machines are able to automatically expand the terms to
+something meaningful and unambiguous, like this:</p>
+
+<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://rdfs.org/sioc/ns#avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<p>Doing this allows JSON to be unambiguously machine-readable without
+requiring developers to drastically change their workflow.</p>
+
+<p class="note">The example above does not use the <code>@id</code> keyword
+to set the <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> of the node being described above. This type
+of node is called an <dfn title="unlabeled_node" id="dfn-unlabeled_node">unlabeled node</dfn> and is considered to be
+a weaker form of <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</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>
+</div>
+</div>
+
+<div id="basic-concepts" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">3. </span>Basic Concepts</h2>
+
+<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>
+
+<div id="iris" class="section">
+<h3><span class="secno">3.1 </span>IRIs</h3>
+
+<p>Expressing <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s 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="subject" href="#dfn-subject">subject</a>s, all
+<a class="tref internalDFN" title="property" href="#dfn-property">properties</a> and many <a class="tref internalDFN" title="object" href="#dfn-object">object</a>s 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>
+
+<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 to an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> or another <a class="tref internalDFN" title="term" href="#dfn-term">term</a> in the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> are expanded to an <abbr title="Internationalized Resource Identifier">IRI</abbr> 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 absolute <abbr title="Internationalized Resource Identifier">IRI</abbr>, an <abbr title="Internationalized Resource Identifier">IRI</abbr> that is relative to the
+base location of the document, 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>:suffix construct.</p>
+
+<p>IRIs can be expressed directly in the key position like so:</p>
+
+<pre class="example">{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}</pre>
+
+<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>, as
+opposed to being interpreted as a string.</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>
+
+<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",
+...
+}</pre>
+
+<p><a class="tref internalDFN" title="prefix" href="#dfn-prefix">Prefix</a>es are expanded when the form of the value is <code>prefix:suffix</code>, 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>
+
+<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>
+
+<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><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="#prefixes">Prefixes</a> for more details.</p>
+
+<p>An <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> is generated when a value is associated with a key using
+the <code>@id</code> keyword:</p>
+
+<pre class="example">{
+...
+ "homepage": { "<span class="diff">@id</span>": "http://manu.sporny.org" }
+...
+}</pre>
+
+<p class="note">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 object using an
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>. This facility <em class="rfc2119" title="may">may</em> also be used to link a
+ <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> with an <a class="tref internalDFN" title="object" href="#dfn-object">object</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">Embedding</a>.</p>
+
+<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>
+
+<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>
+
+<p>Even though the value <code>http://manu.sporny.org/</code> is a
+<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>
+
+</div>
+
+<div id="identifying-the-subject" class="section">
+<h3><span class="secno">3.2 </span>Identifying the Subject</h3>
+
+<p>
+ To be able to externally reference nodes, 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.
+ 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>A <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a>
+ of an object in JSON is declared using the <code>@id</code> key. The subject is the
+first piece of information needed by the JSON-LD processor in order to
+create the (subject, property, object) tuple, also known as a triple.</p>
+
+<pre class="example">{
+...
+ "<span class="diff">@id</span>": "<span class="diff">http://example.org/people#joebob</span>",
+...
+}</pre>
+
+<p>The example above would set the subject to the <abbr title="Internationalized Resource Identifier">IRI</abbr>
+<code>http://example.org/people#joebob</code>.
+</p>
+
+<p class="note">To ensure the best possible performance, it is a best practice
+to put the <code>@id</code> keyword before other key-value pairs in an object.
+If it isn't listed first, processors have to save each key-value pair until
+<code>@id</code> is processed before they can start generating triples.
+Not specifying the <code>@id</code> keyword first creates a memory and
+complexity burden for one-pass processors.</p>
+
+</div>
+
+<div id="specifying-the-type" class="section">
+<h3><span class="secno">3.3 </span>Specifying the Type</h3>
+
+<p>The type of a particular subject can be specified using the
+<code>@type</code> keyword. Specifying the type in this way will generate a
+triple of the form (subject, type, type-<abbr title="Internationalized Resource Identifier">IRI</abbr>). 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>
+
+<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>
+
+<div id="strings" class="section">
+<h3><span class="secno">3.4 </span>Strings</h3>
+
+<p>Regular text strings, also referred to as <dfn title="string_value" id="dfn-string_value">string value</dfn>s, are
+easily expressed using regular JSON <a class="tref internalDFN" title="string" href="#dfn-string">string</a>s.</p>
+
+<pre class="example">{
+...
+ "name": "<span class="diff">Mark Birbeck</span>",
+...
+}</pre>
+
+</div>
+
+<div id="string-internationalization" class="section">
+<h3><span class="secno">3.5 </span>String Internationalization</h3>
+
+<p>JSON-LD makes an assumption that strings with associated language encoding
+information are not very common when used in JavaScript and Web Services.
+Thus, it takes a little more effort to express strings with associated
+language information.</p>
+
+<pre class="example">{
+...
+ "name": <span class="diff">
+ {
+ "@value": "花澄",
+ "@language": "ja"
+ }</span>
+...
+}</pre>
+
+<p>The example above would generate a <a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a> for
+<em>花澄</em> and associate the <code>ja</code> language code with the triple
+that is generated. Languages <em class="rfc2119" title="must">must</em> be expressed in [<cite><a class="bibref" rel="biblioentry" href="#bib-BCP47">BCP47</a></cite>] format.</p>
+
+</div>
+
+
+<div id="typed-values" class="section">
+<h3><span class="secno">3.6 </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> keyword 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 objects.</li>
+ <li>By using a native JSON type.</li>
+</ol>
+
+<p>The first example uses the <code>@type</code> keyword to express a typed value:</p>
+
+<pre class="example">{
+ <span class="diff">"@context": {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "modified": {
+ "@id": "http://purl.org/dc/terms/modified",
+ "@type": "xsd:dateTime"
+ }
+ }</span>
+...
+ "modified": "2010-05-29T14:17:39+02:00",
+...
+}</pre>
+
+<p>The second example uses the expanded form for specifying objects:</p>
+
+<pre class="example">{
+...
+ "modified": <span class="diff">{
+ "@value": "2010-05-29T14:17:39+02:00",
+ "@type": "xsd:dateTime"
+ }</span>
+...
+}</pre>
+
+<p>Both examples above would generate an object with the value of
+<code>2010-05-29T14:17:39+02:00</code> and the type of
+<code>http://www.w3.org/2001/XMLSchema#dateTime</code>.</p>
+
+<p>The third example uses a built-in native JSON type, a
+ <a class="tref internalDFN" title="number" href="#dfn-number">number</a>, to express a type:</p>
+
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "age": <span class="diff">31</span>
+...
+}</pre>
+
+<p>The example above is really just a shorthand for the following:</p>
+
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "age": <span class="diff">{
+ "@value": "31",
+ "@type": "http://www.w3.org/2001/XMLSchema#integer"
+ }</span>
+...
+}</pre>
+
+<p class="note">
+ The <code>@type</code> keyword is also used to associate a type with
+ a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a>. Although the same keyword is used in both places,
+ the concept of an <em>object type</em> and a <em>value type</em>
+ 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>
+
+<div id="multiple-objects-for-a-single-property" class="section">
+<h3><span class="secno">3.7 </span>Multiple Objects for a Single Property</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. If a subject has multiple values for the same property,
+the author <em class="rfc2119" title="may">may</em> express each property as an <a class="tref internalDFN" title="array" href="#dfn-array">array</a>.</p>
+
+<p class="note">In JSON-LD, multiple objects on a property are not ordered.
+This is because graphs are inherently unordered data structures. To learn
+more about creating ordered collections in JSON-LD, see the
+section on <a href="#lists">Lists</a>.
+</p>
+
+<pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}</pre>
+
+<p>The markup shown above would generate the following triples:</p>
+
+<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>
+
+<div id="multiple-values-for-a-single-property" class="section">
+<h3><span class="secno">3.8 </span>Multiple Values for a Single Property</h3>
+
+<p>Multiple <a class="tref internalDFN" title="value" href="#dfn-value">value</a>s may also be expressed using the expanded
+form for <a class="tref internalDFN" title="object" href="#dfn-object">object</a>s:</p>
+
+<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>
+
+<p>The markup shown above would generate the following triples:</p>
+
+<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>
+
+<div id="lists" class="section">
+ <h3><span class="secno">3.9 </span>Lists</h3>
+ <p>
+ Because graphs do not describe ordering for links between nodes, in contrast to plain JSON, multi-valued properties
+ in JSON-LD do not provide an ordering of the listed objects. For example, consider the following
+ simple document:
+ </p>
+ <pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}</pre>
+ <p>
+ This results in three triples being generated, each relating the subject
+ to an individual object, with no inherent order.</p>
+ <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> keyword as follows:
+ </p>
+ <pre class="example">{
+...
+ "@id": "http://example.org/people#joebob",
+ "foaf:nick": <span class="diff">{ "@list": [ "joe", "bob", "jaybee" ] }</span>,
+...
+}</pre>
+ <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 through alternate representations as
+ described in [<cite><a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>]. If every use of a given multi-valued property
+ is a list, this may be abbreviated by adding a
+ <code>@type</code> <a class="tref internalDFN" title="coercion" href="#dfn-coercion">coercion</a>:
+ </p>
+ <pre class="example">{
+ <span class="diff">"@context": {
+ ...
+ "nick": {
+ "@id": "http://xmlns.com/foaf/0.1/nick",
+ "@list": true
+ }
+}</span>,
+...
+ "@id": "http://example.org/people#joebob",
+ "nick": <span class="diff">[ "joe", "bob", "jaybee" ]</span>,
+...
+}</pre>
+ <p>List coercion is specified within an expanded <a class="tref internalDFN" title="term" href="#dfn-term">term</a> definition using the <code>@list</code> key.
+ The value of this key, if present, <em class="rfc2119" title="must">must</em> be <code>true</code>.
+ This indicates that array values of keys coerced as <code>@list</code> are to be serialized
+ as a <a href="#lists">List</a>.</p>
+</div>
+
+</div>
+
+<div id="advanced-concepts" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">4. </span>Advanced Concepts</h2>
+
+<p>JSON-LD has a number of features that provide functionality above and beyond
+the core functionality described above. The following sections outline the
+features that are specific to JSON-LD.
+</p>
+
+<div id="prefixes" class="section">
+ <h3><span class="secno">4.1 </span>Prefixes</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 term 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 three 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, the second is the serialized size of the
+ <a class="tref internalDFN" title="context" href="#dfn-context">context</a> if it is specified inline, the third is
+ future-proofing embedded application <a class="tref internalDFN" title="context" href="#dfn-context">context</a>s that may not
+ be easy to change after they are deployed. In order to address these issues,
+ the concept of a <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> mechanism is introduced.</p>
+ <p>
+ A <dfn title="prefix" id="dfn-prefix">prefix</dfn> is a compact way of expressing a base
+ <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> for a <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a>.
+ Generally, these prefixes are used by concatenating the <em>prefix</em> and
+ a <em>suffix</em>, which is separated by a colon (<code>:</code>).
+ The <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a> 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 absolute <abbr title="Internationalized Resource Identifier">IRI</abbr> 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>To generate an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a> out of a <code>prefix:suffix</code>
+ construct, 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 used
+ directly as an <abbr title="Internationalized Resource Identifier">IRI</abbr>. If the prefix is an underscore
+ (<code>_</code>), the <abbr title="Internationalized Resource Identifier">IRI</abbr> remains unchanged.
+ </p>
+ <p>
+ The ability to use <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>es reduces the need for developers
+ to declare every <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> term that they intend to use in
+ the JSON-LD <a class="tref internalDFN" title="context" href="#dfn-context">context</a>. This reduces stand-alone JSON-LD
+ document serialization size because every <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> term
+ need not be declared in the embedded context.
+ <a class="tref internalDFN" title="prefix" href="#dfn-prefix">Prefix</a> also
+ reduces the cognitive load on the developer. It is far easier to
+ remember <code>foaf:name</code> than it is to remember
+ <code>http://xmlns.com/foaf/0.1/name</code>. The use of prefixes also
+ ensures that a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> document does not have to be updated
+ in lock-step with an externally defined <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a>.
+ Without prefixes, a developer would need to keep their application
+ context terms in lock-step with an externally defined vocabulary. Rather,
+ by just declaring the <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> prefix, one can use new
+ terms as they're declared without having to update the application's
+ JSON-LD <a class="tref internalDFN" title="context" href="#dfn-context">context</a>.
+ </p>
+ <p>Consider the following example:</p>
+ <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>
+ <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 <code>prefix:suffix</code> notation.
+ </p>
+ <p>
+ Prefixes, also known as CURIEs, are defined more formally in RDFa Core 1.1,
+ <cite><a href="http://www.w3.org/TR/rdfa-core/#s_curies">Section 6
+ "CURIE Syntax Definition"</a></cite> [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>].
+ JSON-LD does not support the square-bracketed CURIE syntax as the
+ mechanism is not required to disambiguate <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s in a JSON-LD
+ document like it is in HTML documents.
+ </p>
+</div>
+
+<div id="external-contexts" class="section">
+<h3><span class="secno">4.2 </span>External Contexts</h3>
+
+<p>Authors may choose to declare JSON-LD <a class="tref internalDFN" title="context" href="#dfn-context">context</a>s in external
+documents to promote re-use of contexts as well as reduce the size of JSON-LD
+documents.
+</p>
+
+<p>
+In order to use an external context, an author <em class="rfc2119" title="may">may</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. The referenced document <em class="rfc2119" title="must">must</em> have a
+top-level <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON Object</a>. The value of any <code>@context</code> key
+within that object is substituted for the <abbr title="Internationalized Resource Identifier">IRI</abbr> within the referencing document
+to have the same effect as if the value were specified inline within the
+referencing document.</p>
+
+<p>The following example demonstrates the use of an external context:</p>
+
+<pre class="example">{
+ <span class="diff">"@context": "http://json-ld.org/contexts/person"</span>,
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<p>Authors may also import multiple contexts or a combination of external
+and local contexts by specifying a list of contexts:</p>
+
+<pre class="example">{
+ <span class="diff">"@context":
+ [
+ "http://json-ld.org/contexts/person",
+ { "foaf": "http://xmlns.com/foaf/0.1/" },
+ "http://json-ld.org/contexts/event",
+ ]</span>
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/",
+ "depiction": "http://twitter.com/account/profile_image/manusporny"
+ <span class="diff">"celebrates":
+ {
+ "@type": "Event",
+ "description": "International Talk Like a Pirate Day",
+ "date": "R/2011-09-19"
+ }</span>
+}</pre>
+
+<p>Each context in a list will be evaluated in-order. Duplicate mappings among
+the <a class="tref internalDFN" title="context" href="#dfn-context">context</a>s <em class="rfc2119" title="must">must</em> be overwritten on a last-defined-overrides
+basis. The context list <em class="rfc2119" title="must">must</em> contain either de-referenceable <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s
+or <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON Object</a>s that conform to the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> syntax
+as described in this document.</p>
+
+<p>An author may nest contexts within <a class="tref internalDFN" title="json_object" href="#dfn-json_object">JSON object</a>s, with the
+more deeply nested contexts overriding the values in previously defined
+contexts:</p>
+
+<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",
+ ...
+ "details":
+ {
+ <span class="diff">"@context": { "name": "http://example.com/organization#name" },</span>
+ "<span class="diff">name</span>": "Acme, Ltd."
+ }
+}</pre>
+
+<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 the
+JSON object has legacy applications using the structure of the object.</p>
+
+<p>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="prefix" href="#dfn-prefix">prefix</a>es 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. It is
+also <em class="rfc2119" title="recommended">recommended</em> that a human-readable document encoded in HTML+RDFa
+[<cite><a class="bibref" rel="biblioentry" href="#bib-HTML-RDFA">HTML-RDFA</a></cite>] or other Linked Data compatible format is served as well to
+explain the correct usage of the JSON-LD context document.
+</p>
+
+</div>
+
+<div id="default-language" class="section">
+<h3><span class="secno">4.3 </span>Default Language</h3>
+
+<p>JSON-LD allows a default value to use as the language for
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a>s. It is commonly the case that documents are
+written using a single language. As described in
+<a href="string-internationalization">String Internationalization</a>, a
+language-tagged value <em class="rfc2119" title="may">may</em> be specified as follows:</p>
+
+<pre class="example">{
+...
+ "name":
+ {
+ "@value": "花澄",
+ "@language": "ja"
+ }
+...
+}</pre>
+
+<p>It is also possible to apply a particular language code to all
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a>s by setting the <code>@language</code> key in the
+<code>@context</code>:</p>
+
+<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>
+
+<p>The example above would generate a <a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a> for
+<em>花澄</em> and <em>科学者</em> and associate the <code>ja</code> language
+code with each value.</p>
+
+<p>It is possible to override the default language by using the expanded
+form of a value:</p>
+
+<pre class="example">{
+ "@context:"
+ {
+ "@language": "ja"
+ },
+...
+ "name": "花澄"
+ "occupation": <span class="diff">
+ {
+ "@value": "Scientist",
+ "@language": "en"
+ }</span>
+...
+}</pre>
+
+<p>It is also possible to override the default language and specify a plain
+value by omitting the <code>@language</code> tag when expressing the
+expanded value:</p>
+
+<pre class="example">{
+ "@context:"
+ {
+ "@language": "ja"
+ },
+...
+ "name": "花澄"
+ "occupation": <span class="diff">
+ {
+ "@value": "Ninja"
+ }</span>
+...
+}</pre>
+
+<p>Object <a class="tref internalDFN" title="property" href="#dfn-property">properties</a> that use the expanded form
+are considered explicitly defined. The <code>@language</code> keyword,
+when used in the <a class="tref internalDFN" title="context" href="#dfn-context">context</a>, <em class="rfc2119" title="must">must</em> only be applied to
+<a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a>s. That is, <a class="tref internalDFN" title="string_value" href="#dfn-string_value">string value</a>s expressed in
+expanded form are not affected by the <code>@language</code> keyword, when
+it is used in the <a class="tref internalDFN" title="context" href="#dfn-context">context</a>.
+</p>
+
+</div>
+
+<div id="expanded-term-definition" class="section">
+ <h3><span class="secno">4.4 </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 term to be specified (see
+ <a href="#type-coerceion">Type Coercion</a> and
+ <a href="#lists">Lists</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 an object 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="prefix" href="#dfn-prefix">prefix</a>:suffix value, an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>. Type information
+ may be specified</p>
+
+<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>
+
+<div id="automatic-typing" class="section">
+<h3><span class="secno">4.5 </span>Automatic Typing</h3>
+
+<p>Since JSON is capable of expressing typed information such as doubles,
+integers, and boolean values. As demonstrated below, JSON-LD utilizes that
+information to create <a class="tref internalDFN" title="typed_value" href="#dfn-typed_value">typed value</a>s:</p>
+
+<pre class="example">{
+...
+ // The following two values are automatically converted to a type of xsd:double
+ // and both values are equivalent to each other.
+ "measure:cups": <span class="diff">5.3</span>,
+ "measure:cups": <span class="diff">5.3e0</span>,
+ // The following value is automatically converted to a type of xsd:double as well
+ "space:astronomicUnits": <span class="diff">6.5e73</span>,
+ // The following value is never converted to a language-native type
+ "measure:stones": <span class="diff">{ "@value": "4.8", "@type": "xsd:decimal" }</span>,
+ // This value is automatically converted to having a type of xsd:integer
+ "chem:protons": <span class="diff">12</span>,
+ // This value is automatically converted to having a type of xsd:boolean
+ "sensor:active": <span class="diff">true</span>,
+...
+}</pre>
+
+<p class="note">When dealing with a number of modern programming languages,
+including JavaScript ECMA-262, there is no distinction between
+<strong>xsd:decimal</strong> and <strong>xsd:double</strong> values. That is,
+the <a class="tref internalDFN" title="number" href="#dfn-number">number</a> <code>5.3</code> and the <a class="tref internalDFN" title="number" href="#dfn-number">number</a>
+<code>5.3e0</code> are treated as if they were the same. When converting from
+JSON-LD to a language-native format and back, type information is lost in a
+number of these languages. Thus, one could say that <code>5.3</code> is a
+<strong>xsd:decimal</strong> and <code>5.3e0</code> is an
+<strong>xsd:double</strong> in JSON-LD, but when both values are
+converted to a language-native format the type difference between the two
+is lost because the machine-level representation will almost always be a
+<strong>double</strong>.
+Implementers should be aware of this potential round-tripping issue between
+<strong>xsd:decimal</strong> and <strong>xsd:double</strong>. Specifically
+objects with a type of <strong>xsd:decimal</strong> <em class="rfc2119" title="must not">must not</em> be converted
+to a language native type.
+</p>
+
+</div>
+
+<div id="type-coercion" class="section">
+<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 types 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
+property types. Using type coercion, value representation is preserved without requiring
+the data type to be specified with each usage.</p>
+
+<p>Type coercion is specified within an <a href="#expanded-term-definition">expanded term definition</a>
+ using the <code>@type</code> key. The values of this key represent type IRIs and <em class="rfc2119" title="must">must</em> take the form of
+ <a class="tref internalDFN" title="term" href="#dfn-term">term</a>, <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>:suffix, absolute <abbr title="Internationalized Resource Identifier">IRI</abbr> or the keyword <code>@id</code>. Specifying
+ <code>@id</code> indicates that within the body of a JSON-LD document, string values of keys coerced as
+ <code>@id</code> are to be interpreted as <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>s.</p>
+
+<p><a class="tref internalDFN" title="term" href="#dfn-term">Terms</a> or <a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefixes</a> used as the value of a
+ <code>@type</code> key <em class="rfc2119" title="may">may</em> be defined within the same context.</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>
+
+<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", "@list": true }</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>
+
+<p>The example above would generate the following Turtle:</p>
+
+<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>
+
+<div id="iri-expansion-within-a-context" class="section">
+ <h3><span class="secno">4.7 </span><abbr title="Internationalized Resource Identifier">IRI</abbr> Expansion Within a Context</h3>
+ <p>To be consistent with JSON-LD, in general, anywhere an <abbr title="Internationalized Resource Identifier">IRI</abbr> is expected,
+ normal <abbr title="Internationalized Resource Identifier">IRI</abbr> expansion rules apply (see <a href="#iris">IRIs</a>). Within
+ a <a class="tref internalDFN" title="context" href="#dfn-context">context</a> definition, this can mean that terms defined
+ within a given 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>
+<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>
+<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>
+
+<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>
+
+<p>
+<a class="tref internalDFN" title="term" href="#dfn-term">Term</a>s <em class="rfc2119" title="may">may</em> also be used on the left-hand side of a definition.
+</p>
+
+<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>": {"@id": "foaf:age", "@type": xsd:integer"},
+ "<span class="diff">foaf:homepage</span>": <span class="diff">{ "@type": "@id" }</span>
+ },
+ ...
+}</pre>
+
+<p>
+Note that in this example, the prefixed form is used in two different ways.
+The first way, as shown with <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 term (using short-form) as well as the
+<code>@type</code> associated with the <a class="tref internalDFN" title="term" href="#dfn-term">term</a>. The second way, only
+declares the <code>@type</code> associated with the <a class="tref internalDFN" title="term" href="#dfn-term">term</a>. In the
+second case, the JSON-LD processor will still derive the full <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>
+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> for <code>foaf:homepage</code>.
+</p>
+
+<p>
+Full IRIs <em class="rfc2119" title="may">may</em> also be used on the left-hand side of a <a class="tref internalDFN" title="context" href="#dfn-context">context</a>:
+</p>
+
+<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>
+
+<p>
+Note that in order for the full <abbr title="Internationalized Resource Identifier">IRI</abbr> to match above, the full <abbr title="Internationalized Resource Identifier">IRI</abbr> <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>
+<pre class="example">{
+ "@context":
+ {
+ <span class="diff">"term1": {"@id": "term2:foo"},
+ "term2": {"@id": "term1:bar"}</span>
+ },
+ ...
+}</pre>
+</div>
+
+<div id="embedding" class="section">
+ <h3><span class="secno">4.8 </span>Embedding</h3>
+ <p>
+ Object <dfn title="embedding" id="dfn-embedding">embedding</dfn> is a JSON-LD feature that allows an author to
+ use the definition of JSON-LD objects 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="subject" href="#dfn-subject">subject</a>s.
+ </p>
+ <p>The example shows an two subjects related by a property from the first
+ subject:</p>
+
+ <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>
+
+ <p>
+ An object definition, like the one used above, <em class="rfc2119" title="may">may</em> be used as a
+ JSON value at any point in JSON-LD.
+ </p>
+</div>
+
+<div id="identifying-unlabeled-nodes" class="section">
+<h3><span class="secno">4.9 </span>Identifying Unlabeled Nodes</h3>
+
+<p>At times, it becomes necessary to be able to express information without
+being able to specify the subject. Typically, this type of node is called
+an unlabeled node or a blank node. In JSON-LD, unlabeled node identifiers are
+automatically created if a subject is not specified using the
+<code>@id</code> keyword. However, authors may provide identifiers for
+unlabeled nodes by using the special <code>_</code> (underscore)
+<a class="tref internalDFN" title="prefix" href="#dfn-prefix">prefix</a>. This allows to reference the node locally within the
+document but not in an external document.</p>
+
+<pre class="example">{
+...
+ "@id": "<span class="diff">_:foo</span>",
+...
+}</pre>
+
+<p>The example above would set the subject to <code>_:foo</code>, which can
+then be used later on in the JSON-LD markup to refer back to the
+unlabeled node. This practice, however, is usually frowned upon when
+generating <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>. If a developer finds that they refer to the unlabeled
+node more than once, they should consider naming the node using a resolve-able
+<a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a>.
+</p>
+
+</div>
+
+<div id="aliasing-keywords" class="section">
+<h3><span class="secno">4.10 </span>Aliasing Keywords</h3>
+
+<p>JSON-LD allows all of the syntax keywords, except for <code>@context</code>,
+to be aliased. This feature allows more legacy JSON content to be supported
+by JSON-LD. It 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>
+
+<pre class="example">{
+ "@context":
+ {
+ <span class="diff">"url": "@id"</span>,
+ <span class="diff">"a": "@type"</span>,
+ "name": "http://schema.org/name"
+ },
+ "url": "http://example.com/about#gregg",
+ "a": "http://schema.org/Person",
+ "name": "Gregg Kellogg"
+}</pre>
+
+<p>In the example above, the <code>@id</code> and <code>@type</code>
+keywords have been given the aliases <strong>url</strong> and
+<strong>a</strong>, respectively.
+</p>
+
+</div>
+
+</div>
+
+<div class="appendix informative section" id="markup-examples">
+
+<!-- OddPage -->
+<h2><span class="secno">A. </span>Markup Examples</h2><p><em>This section is non-normative.</em></p>
+
+<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 [<cite><a class="bibref" rel="biblioentry" 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 such as Turtle, RDFa, Microformats,
+ and Microdata. These sections are merely provided as proof 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.
+ Details of transforming JSON-LD into RDF are defined in [<cite><a class="bibref" rel="biblioentry" href="#bib-JSON-LD-API">JSON-LD-API</a></cite>].</p>
+
+<div id="turtle" class="section">
+ <h3><span class="secno">A.1 </span>Turtle</h3>
+
+ <p>The following are examples of representing <a class="tref internalDFN" title="rdf" href="#dfn-rdf">RDF</a> as expressed in [<cite><a class="bibref" rel="biblioentry" href="#bib-TURTLE">TURTLE</a></cite>] into JSON-LD.</p>
+
+<div id="prefix-definitions" class="section">
+<h4><span class="secno">A.1.1 </span>Prefix definitions</h4>
+<p>The JSON-LD context has direct equivalents for the Turtle <code>@prefix</code> declaration:</p>
+
+<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>
+
+<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 class="note">
+<p>JSON-LD has no equivalent for the Turtle <code>@base</code> declaration. Authors could, of course,
+ use a prefix definition to resolve relative IRIs. For example, an empty prefix could be used
+ to get a similar effect to <code>@base</code>:</p>
+<pre class="example">{
+ "@context": {
+ <span class="diff">"": "http://manu.sporny.org/",</span>
+ "foaf": "http://xmlns.com/foaf/0.1/"
+ },
+ "@id": <span class="diff">":i/public"</span>,
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": { "@id": <span class="diff">":" </span>}
+}</pre>
+</div>
+</div>
+
+<div id="embedding-1" class="section">
+<h4><span class="secno">A.1.2 </span>Embedding</h4>
+<p>Both Turtle and JSON-LD allow embedding of objects, although Turtle only allows embedding of objects which
+ use unlabeled node identifiers.</p>
+</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>
+
+<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 id="lists-1" class="section">
+<h4><span class="secno">A.1.3 </span>Lists</h4>
+<p>Both JSON-LD and Turtle can represent sequential lists of values.</p>
+
+<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>
+
+<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", "jaybe" ] }
+}</pre>
+</div>
+
+</div>
+
+<div id="rdfa" class="section">
+<h3><span class="secno">A.2 </span>RDFa</h3>
+
+<p>The following example describes three people with their respective names and
+homepages.</p>
+
+<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>
+
+<p>An example JSON-LD implementation is described below, however, there are
+other ways to mark-up this information such that the <a class="tref internalDFN" title="context" href="#dfn-context">context</a> is not
+repeated.</p>
+
+<pre class="example">{
+ "@context": { "foaf": "http://xmlns.com/foaf/0.1/" },
+ "@id": [
+ {
+ "@id": "_:bnode1",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/bob/",
+ "foaf:name": "Bob"
+ },
+ {
+ "@id": "_:bnode2",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/eve/",
+ "foaf:name": "Eve"
+ },
+ {
+ "@id": "_:bnode3",
+ "@type": "foaf:Person",
+ "foaf:homepage": "http://example.com/manu/",
+ "foaf:name": "Manu"
+ }
+ ]
+}</pre>
+
+</div>
+
+<div id="microformats" class="section">
+<h3><span class="secno">A.3 </span>Microformats</h3>
+
+<p>The following example uses a simple Microformats hCard example to express
+how the Microformat is represented in JSON-LD.</p>
+
+<pre class="example"><div class="vcard">
+ <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</div></pre>
+
+<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>
+
+<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"
+ },
+ "@id": "_:bnode1",
+ "@type": "vcard",
+ "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+}</pre>
+
+</div>
+
+<div id="microdata" class="section">
+<h3><span class="secno">A.4 </span>Microdata</h3>
+
+<p>The microdata example below expresses book information as a microdata Work
+item.
+</p>
+
+<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>
+
+<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>
+
+<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>
+</div>
+
+<div class="appendix section" id="linked-data">
+
+<!-- OddPage -->
+<h2><span class="secno">B. </span>Linked Data</h2>
+<p>
+The following definition for <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> is the one that will
+be used for this specification.
+</p>
+<ol>
+ <li><dfn title="linked_data" id="dfn-linked_data">Linked Data</dfn> is a set of documents, each containing a representation of a linked data graph.</li>
+ <li>A <dfn title="linked_data_graph" id="dfn-linked_data_graph">linked data graph</dfn> is an unordered labeled directed graph, where nodes are <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a>s or <a class="tref internalDFN" title="object" href="#dfn-object">object</a>s, and edges are properties.</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" rel="biblioentry" 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>.</li>
+ <li>An object <em class="rfc2119" title="may">may</em> be a <a class="tref internalDFN" title="subject" href="#dfn-subject">subject</a> and <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 an edge of the <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 labeled with 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="object" href="#dfn-object">object</a> or <a class="tref internalDFN" title="property" href="#dfn-property">property</a>.</li>
+ <li>A <dfn title="value" id="dfn-value">value</dfn> is an <a class="tref internalDFN" title="object" href="#dfn-object">object</a> with a label that is not an <a class="tref internalDFN" title="iri" href="#dfn-iri"><abbr title="Internationalized Resource Identifier">IRI</abbr></a></li>
+</ol>
+
+<p>
+Note that the definition for <a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a> above is silent on the
+topic of unlabeled nodes. Unlabeled nodes are not considered
+<a class="tref internalDFN" title="linked_data" href="#dfn-linked_data">Linked Data</a>. However, this specification allows for the expression
+of unlabled nodes, 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>
+</div>
+
+<div class="appendix informative section" id="mashing-up-vocabularies">
+
+<!-- OddPage -->
+<h2><span class="secno">C. </span>Mashing Up Vocabularies</h2><p><em>This section is non-normative.</em></p>
+
+<p>Developers benefit by being able to mash other
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a> into their
+JSON-LD markup. There are over 200
+<a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a> that are available for use
+on the Web today. Some of these <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a>
+include:
+</p>
+
+<ul>
+ <li>RDF - for describing information about objects and concepts on the Web.</li>
+ <li>RDFS - for expressing things like labels and comments.</li>
+ <li>XSD - for specifying basic types like strings, integers, dates and times.</li>
+ <li>Dublin Core - for describing creative works.</li>
+ <li>FOAF - for describing social networks.</li>
+ <li>Calendar - for specifying events.</li>
+ <li>SIOC - for describing discussions on blogs and websites.</li>
+ <li>CCrel - for describing Creative Commons and other types of licenses.</li>
+ <li>GEO - for describing geographic location.</li>
+ <li>VCard - for describing organizations and people.</li>
+ <li>DOAP - for describing projects.</li>
+</ul>
+
+<p>You can use these <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabularies</a> in
+combination, like so:</p>
+
+<pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",<span class="diff">
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#"</span>
+ },
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": "http://manu.sporny.org/",<span class="diff">
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
+ "rdfs:comment": "Likes puppies, unicorns and rainbows."</span>
+}</pre>
+
+<p>Developers can also specify their own <a class="tref internalDFN" title="vocabulary" href="#dfn-vocabulary">vocabulary</a> documents
+by modifying the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> in-line using
+the <code>@context</code> keyword, like so:</p>
+
+<pre class="example">{
+ "@context":
+ {
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
+ <span class="diff">"myvocab": "http://example.org/myvocab#"</span>
+ },
+ "@type": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": "http://manu.sporny.org/",
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny",
+ "rdfs:comment": "Likes puppies, unicorns and rainbows."
+ <span class="diff">"myvocab:personality": "friendly"</span>
+}</pre>
+
+</div>
+
+<div class="appendix informative section" id="iana-considerations">
+
+<!-- OddPage -->
+<h2><span class="secno">D. </span>IANA Considerations</h2><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 W3C Recommendation.</p>
+
+<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. Valid
+ values include; <code>compacted</code>, <code>expanded</code>,
+ and <code>normalized</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 for an HTTP client, 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/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, Dave Longley</dd>
+ <dt>Change controller:</dt>
+ <dd>W3C</dd>
+</dl>
+
+</div>
+
+<div class="appendix informative section" id="acknowledgements">
+
+<!-- OddPage -->
+<h2><span class="secno">E. </span>Acknowledgements</h2><p><em>This section is non-normative.</em></p>
+
+<p>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,
+Dave Longley, Dave Lehn and Mike Johnson who reviewed, provided feedback, and
+performed several implementations of the specification, and Ian Davis, who
+created RDF/JSON. Thanks also to Nathan Rixham, Bradley P. Allen,
+Kingsley Idehen, Glenn McDonald, Alexandre Passant, Danny Ayers, Ted
+Thibodeau Jr., Olivier Grisel, Niklas Lindström, Markus Lanthaler, and Richard
+Cyganiak for their input on the specification.
+</p>
+</div>
+
+
+
+<div id="references" class="appendix section">
+<!-- OddPage -->
+<h2><span class="secno">F. </span>References</h2><div id="normative-references" class="section"><h3><span class="secno">F.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/rfc/bcp/bcp47.txt"><cite>Tags for Identifying Languages</cite></a> September 2009. IETF Best Current Practice. URL: <a href="http://tools.ietf.org/rfc/bcp/bcp47.txt">http://tools.ietf.org/rfc/bcp/bcp47.txt</a>
+</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-WEBIDL">[WEBIDL]</dt><dd>Cameron McCormack. <a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/"><cite>Web IDL.</cite></a> 27 September 2011. W3C Working Draft. (Work in progress.) URL: <a href="http://www.w3.org/TR/2011/WD-WebIDL-20110927/">http://www.w3.org/TR/2011/WD-WebIDL-20110927/</a>
+</dd></dl></div><div id="informative-references" class="section"><h3><span class="secno">F.2 </span>Informative references</h3><dl class="bibliography"><dt id="bib-ECMA-262">[ECMA-262]</dt><dd><a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm"><cite>ECMAScript Language Specification.</cite></a> December 1999. URL: <a href="http://www.ecma-international.org/publications/standards/Ecma-262.htm">http://www.ecma-international.org/publications/standards/Ecma-262.htm</a>
+</dd><dt id="bib-HTML-RDFA">[HTML-RDFA]</dt><dd>Manu Sporny; et al. <a href="http://www.w3.org/TR/rdfa-in-html/"><cite>HTML+RDFa</cite></a> 04 March 2010. W3C Working Draft. URL: <a href="http://www.w3.org/TR/rdfa-in-html/">http://www.w3.org/TR/rdfa-in-html/</a>
+</dd><dt id="bib-JSON-LD-API">[JSON-LD-API]</dt><dd>Manu Sporny, Gregg Kellogg, Dave Longley, Eds. <cite><a href="http://json-ld.org/spec/latest/json-ld-api/">JSON-LD API</a></cite> Latest. W3C Editor's Draft. URL: <a href="http://json-ld.org/spec/latest/json-ld-api/">http://json-ld.org/spec/latest/json-ld-api/</a>
+</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-RDFA-CORE">[RDFA-CORE]</dt><dd>Shane McCarron; et al. <a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215"><cite>RDFa Core 1.1: Syntax and processing rules for embedding RDF through attributes.</cite></a> 15 December 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-rdfa-core-20111215">http://www.w3.org/TR/2011/WD-rdfa-core-20111215</a>
+</dd><dt id="bib-TURTLE">[TURTLE]</dt><dd>David Beckett, Tim Berners-Lee. <a href="http://www.w3.org/TeamSubmission/turtle/"><cite>Turtle: Terse RDF Triple Language.</cite></a> January 2008. W3C Team Submission. URL: <a href="http://www.w3.org/TeamSubmission/turtle/">http://www.w3.org/TeamSubmission/turtle/</a>
+</dd><dt id="bib-XML-NAMES">[XML-NAMES]</dt><dd>Richard Tobin; et al. <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/"><cite>Namespaces in XML 1.0 (Third Edition).</cite></a> 8 December 2009. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2009/REC-xml-names-20091208/">http://www.w3.org/TR/2009/REC-xml-names-20091208/</a>
+</dd></dl></div></div></body></html>
--- a/spec/latest/json-ld-syntax/index.html Sun Jan 22 14:28:55 2012 -0500
+++ b/spec/latest/json-ld-syntax/index.html Sun Jan 22 14:59:39 2012 -0500
@@ -221,7 +221,7 @@
wgPatentURI: "",
maxTocLevel: 4,
preProcess: [ preProc ],
- alternateFormats: [ {uri: "diff-20111023.html", label: "diff to previous version"} ],
+ alternateFormats: [ {uri: "diff-20120112.html", label: "diff to previous version"} ],
};
function updateExample(doc, content) {
@@ -295,7 +295,7 @@
</p> -->
</section>
-<section>
+<section class="informative">
<h1>Introduction</h1>
<p>
@@ -461,7 +461,7 @@
</section>
-<section>
+<section class="informative">
<h1>Design</h1>
<p>The following section outlines the design goals and rationale behind the
@@ -1905,7 +1905,7 @@
</section>
-<section class="appendix">
+<section class="appendix informative">
<h2>Markup Examples</h2>
<p>JSON-LD is a specification for representing <tref>Linked Data</tref> in JSON. A common
@@ -2230,7 +2230,7 @@
</p>
</section>
-<section class="appendix">
+<section class="appendix informative">
<h3>Mashing Up Vocabularies</h3>
<p>Developers benefit by being able to mash other
@@ -2303,7 +2303,7 @@
</section>
-<section class="appendix">
+<section class="appendix informative">
<h1>IANA Considerations</h1>
<p>This section is included merely for standards community review and will be
@@ -2372,7 +2372,7 @@
</section>
-<section class="appendix">
+<section class="appendix informative">
<h1>Acknowledgements</h1>
<p>The editors would like to thank Mark Birbeck, who provided a great deal of