Created time-stamped Editors Draft for JSON-LD Syntax.
authorManu Sporny <msporny@digitalbazaar.com>
Sun, 22 Jan 2012 14:59:39 -0500
changeset 354 90b49f791599
parent 353 1983190e5a99
child 355 1a3d47f539cf
Created time-stamped Editors Draft for JSON-LD Syntax.
spec/ED/json-ld-syntax/20120122/diff-20120112.html
spec/ED/json-ld-syntax/20120122/index.html
spec/latest/json-ld-syntax/index.html
--- /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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[email protected] screen {
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+</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
+&quot;Web
+of
+Knowledge&quot;.
+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>
[email protected]
+</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>
[email protected]
+</code>
+keyword
+is
+described
+in
+detail
+in
+the
+section
+titled
+<a href="#the-context">
+The
+Context
+</a>.
+</dd>
+<dt>
+<code>
[email protected]
+</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>
[email protected]
+</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>
[email protected]
+</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>
[email protected]
+</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>
[email protected]
+</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/">
[email protected]
+</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>
[email protected]
+</code>
+and
+<code>
[email protected]
+</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">{
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</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>
[email protected]
+</code>,
+<code>
[email protected]
+</code>,
+or
+<code>
[email protected]
+</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">{
+  &quot;@context&quot;: 
+  {
+    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
+    &quot;depiction&quot;: 
+    {
+       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
+       &quot;@type&quot;: &quot;@id&quot;
+    },
+    &quot;homepage&quot;: 
+    {
+       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
+       &quot;@type&quot;: &quot;@id&quot;
+    },
+  }
+}
+</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">&quot;@context&quot;: &quot;http://json-ld.org/contexts/person&quot;,</span>
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</pre>
+<p>
+The
+additions
+above
+transform
+the
+previous
+JSON
+document
+into
+a
+JSON
+document
+with
+added
+semantics
+because
+the
+<code>
[email protected]
+</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">&quot;@context&quot;: 
+  {
+    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
+    &quot;depiction&quot;: 
+    {
+       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;,
+       &quot;@type&quot;: &quot;@id&quot;
+    },
+    &quot;homepage&quot;: 
+    {
+       &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;,
+       &quot;@type&quot;: &quot;@id&quot;
+    },
+  },</span>
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</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">&quot;@context&quot;: [
+    &quot;http://json-ld.org/contexts/person&quot;,
+    {
+      &quot;pic&quot;: &quot;http://xmlns.com/foaf/0.1/depiction&quot;
+    }
+  ],</span>
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  <span class="diff">&quot;pic&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;</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
+&quot;things&quot;
+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">{
+  &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;: &quot;Manu Sporny&quot;,
+  &quot;<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>&quot;: &quot;http://manu.sporny.org&quot;
+  &quot;<span class="diff">http://rdfs.org/sioc/ns#avatar</span>&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</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>
[email protected]
+</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>
[email protected]
+</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>
[email protected]
+</code>
+or
+<code>
[email protected]
+</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>
[email protected]
+</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">{
+...
+  &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot;: &quot;Manu Sporny&quot;,
+...
+}
+</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">{
+  &quot;<span class="diff">@context</span>&quot;: { &quot;<span class="diff">name</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/name</span>&quot; },
+...
+  &quot;<span class="diff">name</span>&quot;: &quot;Manu Sporny&quot;,
+...
+}
+</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">{
+  &quot;<span class="diff">@context</span>&quot;: { &quot;<span class="diff">foaf</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/</span>&quot; },
+...
+  &quot;<span class="diff">foaf:name</span>&quot;: &quot;Manu Sporny&quot;,
+...
+}
+</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>
[email protected]
+</code>
+keyword:
+</p>
+<pre class="example">{
+...
+  &quot;homepage&quot;: { &quot;<span class="diff">@id</span>&quot;: &quot;http://manu.sporny.org&quot; }
+...
+}
+</pre>
+<p class="note">
+Specifying
+a
+<a class="tref internalDFN" title="json_object" href="#dfn-json_object">
+JSON
+Object
+</a>
+with
+an
+<code>
[email protected]
+</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>
[email protected]
+</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">
+  &quot;@context&quot;: 
+  {
+    ...
+    &quot;homepage&quot;: 
+    {
+      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;, 
+      &quot;@type&quot;: &quot;@id&quot;
+    }
+    ...
+  }</span>
+...
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+...
+}
+</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>
[email protected]
+</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">{
+...
+  &quot;<span class="diff">@id</span>&quot;: &quot;<span class="diff">http://example.org/people#joebob</span>&quot;,
+...
+}
+</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>
[email protected]
+</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>
[email protected]
+</code>
+is
+processed
+before
+they
+can
+start
+generating
+triples.
+Not
+specifying
+the
+<code>
[email protected]
+</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>
[email protected]
+</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">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;<span class="diff">@type</span>&quot;: &quot;<span class="diff">http://xmlns.com/foaf/0.1/Person</span>&quot;,
+...
+}
+</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">{
+...
+  &quot;name&quot;: &quot;<span class="diff">Mark Birbeck</span>&quot;,
+...
+}
+</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">{
+...
+  &quot;name&quot;: <span class="diff">
+  {
+    &quot;@value&quot;: &quot;花澄&quot;,
+    &quot;@language&quot;: &quot;ja&quot;
+  }</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>
[email protected]
+</code>
+keyword
+when
+defining
+a
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>
+within
+a
+<code>
[email protected]
+</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>
[email protected]
+</code>
+keyword
+to
+express
+a
+typed
+value:
+</p>
+<pre class="example">{
+  <span class="diff">&quot;@context&quot;: {
+    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
+    &quot;modified&quot;: {
+      &quot;@id&quot;: &quot;http://purl.org/dc/terms/modified&quot;,
+      &quot;@type&quot;: &quot;xsd:dateTime&quot;
+    }
+  }</span>
+...
+  &quot;modified&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
+...
+}
+</pre>
+<p>
+The
+second
+example
+uses
+the
+expanded
+form
+for
+specifying
+objects:
+</p>
+<pre class="example">{
+...
+  &quot;modified&quot;: <span class="diff">{
+    &quot;@value&quot;: &quot;2010-05-29T14:17:39+02:00&quot;,
+    &quot;@type&quot;: &quot;xsd:dateTime&quot;
+  }</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">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;age&quot;: <span class="diff">31</span>
+...
+}
+</pre>
+<p>
+The
+example
+above
+is
+really
+just
+a
+shorthand
+for
+the
+following:
+</p>
+<pre class="example">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;age&quot;: <span class="diff">{
+    &quot;@value&quot;: &quot;31&quot;,
+    &quot;@type&quot;: &quot;http://www.w3.org/2001/XMLSchema#integer&quot;
+  }</span>
+...
+}
+</pre>
+<p class="note">
+The
+<code>
[email protected]
+</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">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;nick&quot;: <span class="diff">[ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]</span>,
+...
+}
+</pre>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">&lt;http://example.org/people#joebob&gt;
+   &lt;http://xmlns.com/foaf/0.1/nick&gt;
+      &quot;joe&quot; .
+&lt;http://example.org/people#joebob&gt;
+   &lt;http://xmlns.com/foaf/0.1/nick&gt;
+      &quot;bob&quot; .
+&lt;http://example.org/people#joebob&gt;
+   &lt;http://xmlns.com/foaf/0.1/nick&gt;
+&quot;jaybee&quot;
+.
+</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">{
+  &quot;@id&quot;: &quot;http://example.org/articles/8&quot;,
+  &quot;dc:title&quot;: <span class="diff">
+  [
+    {&quot;@value&quot;: &quot;Das Kapital&quot;, &quot;@language&quot;: &quot;de&quot;},
+    {&quot;@value&quot;: &quot;Capital&quot;, &quot;@language&quot;: &quot;en&quot;}
+  ]</span>
+}
+</pre>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">&lt;http://example.org/articles/8&gt;
+   &lt;http://purl.org/dc/terms/title&gt;
+      &quot;Das Kapital&quot;@de .
+&lt;http://example.org/articles/8&gt;
+   &lt;http://purl.org/dc/terms/title&gt;
+&quot;Capital&quot;@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">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;nick&quot;: <span class="diff">[ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]</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>
[email protected]
+</code>
+keyword
+as
+follows:
+</p>
+  <pre class="example">{
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;foaf:nick&quot;: <span class="diff">{ &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ] }</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>
[email protected]
+</code>
+<a class="tref internalDFN" title="coercion" href="#dfn-coercion">
+coercion
+</a>:
+</p>
+  <pre class="example">{
+  <span class="diff">&quot;@context&quot;: {
+    ...
+    &quot;nick&quot;: {
+      &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/nick&quot;,
+      &quot;@list&quot;: true
+    }
+}</span>,
+...
+  &quot;@id&quot;: &quot;http://example.org/people#joebob&quot;,
+  &quot;nick&quot;: <span class="diff">[ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybee&quot; ]</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>
[email protected]
+</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>
[email protected]
+</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">{
+  &quot;@context&quot;: {
+    <span class="diff">&quot;dc&quot;: &quot;http://purl.org/dc/elements/1.1/&quot;,</span>
+    <span class="diff">&quot;ex&quot;: &quot;http://example.org/vocab#&quot;</span>
+  },
+  &quot;@id&quot;: &quot;http://example.org/library&quot;,
+  &quot;@type&quot;: <span class="diff">&quot;ex:Library&quot;</span>,
+  <span class="diff">&quot;ex:contains&quot;</span>: {
+    &quot;@id&quot;: &quot;http://example.org/library/the-republic&quot;,
+    &quot;@type&quot;: <span class="diff">&quot;ex:Book&quot;</span>,
+    <span class="diff">&quot;dc:creator&quot;</span>: &quot;Plato&quot;,
+    <span class="diff">&quot;dc:title&quot;</span>: &quot;The Republic&quot;,
+    <span class="diff">&quot;ex:contains&quot;</span>: {
+      &quot;@id&quot;: &quot;http://example.org/library/the-republic#introduction&quot;,
+      &quot;@type&quot;: <span class="diff">&quot;ex:Chapter&quot;</span>,
+      <span class="diff">&quot;dc:description&quot;</span>: &quot;An introductory chapter on The Republic.&quot;,
+      <span class="diff">&quot;dc:title&quot;</span>: &quot;The Introduction&quot;
+    }
+  }
+}
+</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
+&quot;CURIE
+Syntax
+Definition&quot;
+</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>
[email protected]
+</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">&quot;@context&quot;: &quot;http://json-ld.org/contexts/person&quot;</span>,
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</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">&quot;@context&quot;:
+  [
+    &quot;http://json-ld.org/contexts/person&quot;,
+    { &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot; },
+    &quot;http://json-ld.org/contexts/event&quot;,
+  ]</span>
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+  <span class="diff">&quot;celebrates&quot;:
+  {
+    &quot;@type&quot;: &quot;Event&quot;,
+    &quot;description&quot;: &quot;International Talk Like a Pirate Day&quot;,
+    &quot;date&quot;: &quot;R/2011-09-19&quot;
+  }</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">&quot;@context&quot;:
+  {
+    &quot;name&quot;: &quot;http://example.com/person#name&quot;,
+    &quot;details&quot;: &quot;http://example.com/person#details&quot;
+  },</span>
+  &quot;<span class="diff">name</span>&quot;: &quot;Markus&quot;,
+  ...
+  &quot;details&quot;:
+  {
+    <span class="diff">&quot;@context&quot;: { &quot;name&quot;: &quot;http://example.com/organization#name&quot; },</span>
+    &quot;<span class="diff">name</span>&quot;: &quot;Acme, Ltd.&quot;
+  }
+}
+</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>
[email protected]
+</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>
[email protected]
+</code>
+value
+from
+an
+external
+JSON-LD
+context
+document,
+any
+extra
+information
+contained
+outside
+of
+the
+<code>
[email protected]
+</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">{
+...
+  &quot;name&quot;:
+  {
+    &quot;@value&quot;: &quot;花澄&quot;,
+    &quot;@language&quot;: &quot;ja&quot;
+  }
+...
+}
+</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>
[email protected]
+</code>
+key
+in
+the
+<code>
[email protected]
+</code>:
+</p>
+<pre class="example">{
+  <span class="diff">&quot;@context:&quot;
+  {
+    &quot;@language&quot;: &quot;ja&quot;
+  },</span>
+...
+  &quot;name&quot;: <span class="diff">&quot;花澄&quot;</span>
+  &quot;occupation&quot;: <span class="diff">&quot;科学者&quot;</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">{
+  &quot;@context:&quot;
+  {
+     &quot;@language&quot;: &quot;ja&quot;
+  },
+...
+  &quot;name&quot;: &quot;花澄&quot;
+  &quot;occupation&quot;: <span class="diff">
+  {
+    &quot;@value&quot;: &quot;Scientist&quot;,
+    &quot;@language&quot;: &quot;en&quot;
+  }</span>
+...
+}
+</pre>
+<p>
+It
+is
+also
+possible
+to
+override
+the
+default
+language
+and
+specify
+a
+plain
+value
+by
+omitting
+the
+<code>
[email protected]
+</code>
+tag
+when
+expressing
+the
+expanded
+value:
+</p>
+<pre class="example">{
+  &quot;@context:&quot;
+  {
+     &quot;@language&quot;: &quot;ja&quot;
+  },
+...
+  &quot;name&quot;: &quot;花澄&quot;
+  &quot;occupation&quot;: <span class="diff">
+  {
+    &quot;@value&quot;: &quot;Ninja&quot;
+  }</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>
[email protected]
+</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>
[email protected]
+</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>
[email protected]
+</code>
+key.
+The
+value
+of
+the
+<code>
[email protected]
+</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">{
+  &quot;@context&quot;: {
+    &quot;foaf&quot;: <span class="diff">{&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;}</span>,
+    &quot;name&quot;: <span class="diff">{&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;}</span>,
+    &quot;homepage&quot;: <span class="diff">{ &quot;@id&quot;: &quot;foaf:homepage&quot; }</span>,
+    &quot;depiction&quot;: <span class="diff">{ &quot;@id&quot;: &quot;foaf:depiction&quot; }</span>
+  },
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}
+</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.
+  &quot;measure:cups&quot;: <span class="diff">5.3</span>,
+  &quot;measure:cups&quot;: <span class="diff">5.3e0</span>,
+  // The following value is automatically converted to a type of xsd:double as well
+  &quot;space:astronomicUnits&quot;: <span class="diff">6.5e73</span>,
+  // The following value is never converted to a language-native type
+  &quot;measure:stones&quot;: <span class="diff">{ &quot;@value&quot;: &quot;4.8&quot;, &quot;@type&quot;: &quot;xsd:decimal&quot; }</span>,
+  // This value is automatically converted to having a type of xsd:integer
+  &quot;chem:protons&quot;: <span class="diff">12</span>,
+  // This value is automatically converted to having a type of xsd:boolean
+  &quot;sensor:active&quot;: <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>
[email protected]
+</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>
[email protected]
+</code>.
+Specifying
+<code>
[email protected]
+</code>
+indicates
+that
+within
+the
+body
+of
+a
+JSON-LD
+document,
+string
+values
+of
+keys
+coerced
+as
+<code>
[email protected]
+</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>
[email protected]
+</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">{
+  &quot;@context&quot;:
+  {
+     &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
+     &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
+     &quot;age&quot;: <span class="diff">{ &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/age&quot;, &quot;@type&quot;: &quot;xsd:integer&quot; }</span>,
+     &quot;homepage&quot;: <span class="diff">{ &quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;, &quot;@type&quot;: &quot;@id&quot;, &quot;@list&quot;: true }</span>
+  },
+  &quot;name&quot;: &quot;John Smith&quot;,
+  &quot;age&quot;: <span class="diff">&quot;41&quot;</span>,
+  &quot;homepage&quot;: <span class="diff">[ &quot;http://personal.example.org/&quot;, &quot;http://work.example.com/jsmith/&quot; ]</span>
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+Turtle:
+</p>
+<pre class="example">@prefix xsd: &lt;http://www.w3.org/2001/XMLSchema#&gt; .
+[ foaf:name &quot;John Smith&quot;;
+  foaf:age  &quot;41&quot;^^xsd:integer;
+  foaf:homepage ( &lt;http://personal.example.org/&gt; &lt;http://work.example.com/jsmith/&gt; )
+]
+.
+</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">{
+  &quot;@context&quot;: {
+    <span class="diff">&quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;</span>,
+    &quot;name&quot;: &quot;http://xmlns.com/foaf/0.1/name&quot;,
+    &quot;age&quot;: {&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/age&quot;, &quot;@type&quot;: <span class="diff">&quot;xsd:integer&quot;</span>},
+    &quot;homepage&quot;: {&quot;@id&quot;: &quot;http://xmlns.com/foaf/0.1/homepage&quot;, &quot;@type&quot;: &quot;@id&quot;}
+  },
+  ...
+}
+</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>
[email protected]
+</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">{
+  &quot;@context&quot;:
+  {
+    <span class="diff">&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;</span>,
+    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
+    &quot;name&quot;: <span class="diff">&quot;foaf:name&quot;</span>,
+    &quot;age&quot;: {&quot;@id&quot;: <span class="diff">&quot;foaf:age&quot;</span>, &quot;@type&quot;: xsd:integer&quot;},
+    &quot;homepage&quot;: {&quot;@id&quot;: <span class="diff">&quot;foaf:homepage&quot;</span>, &quot;@type&quot;: &quot;@id&quot;}
+  },
+  ...
+}
+</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">{
+  &quot;@context&quot;:
+  {
+    <span class="diff">&quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;</span>,
+    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
+    &quot;name&quot;: &quot;foaf:name&quot;,
+    &quot;<span class="diff">foaf:age</span>&quot;: {&quot;@id&quot;: &quot;foaf:age&quot;, &quot;@type&quot;: xsd:integer&quot;},
+    &quot;<span class="diff">foaf:homepage</span>&quot;: <span class="diff">{ &quot;@type&quot;: &quot;@id&quot; }</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>
[email protected]
+</code>
+associated
+with
+the
+<a class="tref internalDFN" title="term" href="#dfn-term">
+term
+</a>.
+The
+second
+way,
+only
+declares
+the
+<code>
[email protected]
+</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">{
+  &quot;@context&quot;:
+  {
+    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
+    &quot;xsd&quot;: &quot;http://www.w3.org/2001/XMLSchema#&quot;,
+    &quot;name&quot;: &quot;foaf:name&quot;,
+    &quot;foaf:age&quot;: {&quot;@id&quot;: &quot;foaf:age&quot;, &quot;@type&quot;: xsd:integer&quot;},
+    &quot;<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>&quot;: { &quot;@type&quot;: &quot;@id&quot; }
+  },
+  ...
+}
+</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>
+{
+&quot;@type&quot;:
+&quot;@id&quot;
+}
+</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">{
+  &quot;@context&quot;:
+  {
+    <span class="diff">&quot;term1&quot;: {&quot;@id&quot;: &quot;term2:foo&quot;},
+    &quot;term2&quot;: {&quot;@id&quot;: &quot;term1:bar&quot;}</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">{
+...
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;<span class="diff">knows</span>&quot;: {
+    &quot;<span class="diff">@type</span>&quot;: &quot;<span class="diff">Person</span>&quot;,
+    &quot;<span class="diff">name</span>&quot;: &quot;<span class="diff">Gregg Kellogg</span>&quot;,
+  }
+...
+}
+</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>
[email protected]
+</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">{
+...
+  &quot;@id&quot;: &quot;<span class="diff">_:foo</span>&quot;,
+...
+}
+</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>
[email protected]
+</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">{
+  &quot;@context&quot;:
+  {
+     <span class="diff">&quot;url&quot;: &quot;@id&quot;</span>,
+     <span class="diff">&quot;a&quot;: &quot;@type&quot;</span>,
+     &quot;name&quot;: &quot;http://schema.org/name&quot;
+  },
+  &quot;url&quot;: &quot;http://example.com/about#gregg&quot;,
+  &quot;a&quot;: &quot;http://schema.org/Person&quot;,
+  &quot;name&quot;: &quot;Gregg Kellogg&quot;
+}
+</pre>
+<p>
+In
+the
+example
+above,
+the
+<code>
[email protected]
+</code>
+and
+<code>
[email protected]
+</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>
[email protected]
+</code>
+and
+<code>
[email protected]
+</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>
[email protected]
+</code>
+declaration:
+</p>
+<pre class="example">@prefix foaf: &lt;http://xmlns.com/foaf/0.1/&gt; .
+&lt;http://manu.sporny.org/i/public&gt; a foaf:Person;
+  foaf:name &quot;Manu Sporny&quot;;
+foaf:homepage
+&lt;http://manu.sporny.org/&gt;
+.
+</pre>
+<pre class="example">{
+  &quot;@context&quot;: {
+    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
+  },
+  &quot;@id&quot;:            &quot;http://manu.sporny.org/i/public&quot;,
+  &quot;@type&quot;:          &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
+  &quot;foaf:homepage&quot;:  { &quot;@id&quot;: &quot;http://manu.sporny.org/&quot; }
+}
+</pre>
+<div class="note">
+<p>
+JSON-LD
+has
+no
+equivalent
+for
+the
+Turtle
+<code>
[email protected]
+</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>
[email protected]
+</code>:
+</p>
+<pre class="example">{
+  &quot;@context&quot;: {
+    <span class="diff">&quot;&quot;:       &quot;http://manu.sporny.org/&quot;,</span>
+    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
+  },
+  &quot;@id&quot;:            <span class="diff">&quot;:i/public&quot;</span>,
+  &quot;@type&quot;:          &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
+  &quot;foaf:homepage&quot;:  { &quot;@id&quot;: <span class="diff">&quot;:&quot; </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: &lt;http://xmlns.com/foaf/0.1/&gt; .
+&lt;http://manu.sporny.org/i/public&gt; 
+  a foaf:Person;
+  foaf:name &quot;Manu Sporny&quot;;
+foaf:knows
+[
+a
+foaf:Person;
+foaf:name
+&quot;Gregg
+Kellogg&quot;
+]
+.
+</pre>
+<pre class="example">{
+  &quot;@context&quot;: {
+    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
+  },
+  &quot;@id&quot;:            &quot;http://manu.sporny.org/i/public&quot;,
+  &quot;@type&quot;:          &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;:      &quot;Manu Sporny&quot;,
+  &quot;foaf:knows&quot;: {
+    &quot;@type&quot;:        &quot;foaf:Person&quot;,
+    &quot;foaf:name&quot;:    &quot;Gregg Kellogg&quot;
+  }
+}
+</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: &lt;http://xmlns.com/foaf/0.1/&gt; .
+&lt;http://example.org/people#joebob&gt; a foaf:Person;
+  foaf:name &quot;Joe Bob&quot;;
+foaf:nick
+(
+&quot;joe&quot;
+&quot;bob&quot;
+&quot;jaybee&quot;)
+.
+</pre>
+<pre class="example">{
+  &quot;@context&quot;: {
+    &quot;foaf&quot;:   &quot;http://xmlns.com/foaf/0.1/&quot;
+  },
+  &quot;@id&quot;:        &quot;http://example.org/people#joebob&quot;,
+  &quot;@type&quot;:      &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;:  &quot;Joe Bob&quot;,
+  &quot;foaf:nick&quot;:  { &quot;@list&quot;: [ &quot;joe&quot;, &quot;bob&quot;, &quot;jaybe&quot; ] }
+}
+</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">&lt;div <span class="diff">prefix=&quot;foaf: http://xmlns.com/foaf/0.1/&quot;</span>&gt;
+   &lt;ul&gt;
+      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
+        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/bob/&quot; property=&quot;foaf:name&quot; </span>&gt;Bob&lt;/a&gt;
+      &lt;/li&gt;
+      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
+        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/eve/&quot; property=&quot;foaf:name&quot; </span>&gt;Eve&lt;/a&gt;
+      &lt;/li&gt;
+      &lt;li <span class="diff">typeof=&quot;foaf:Person&quot;</span>&gt;
+        &lt;a <span class="diff">rel=&quot;foaf:homepage&quot; href=&quot;http://example.com/manu/&quot; property=&quot;foaf:name&quot; </span>&gt;Manu&lt;/a&gt;
+      &lt;/li&gt;
+   &lt;/ul&gt;
+&lt;/div&gt;
+</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">{
+  &quot;@context&quot;: { &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot; },
+  &quot;@id&quot;: [
+    {
+      &quot;@id&quot;: &quot;_:bnode1&quot;,
+      &quot;@type&quot;: &quot;foaf:Person&quot;,
+      &quot;foaf:homepage&quot;: &quot;http://example.com/bob/&quot;,
+      &quot;foaf:name&quot;: &quot;Bob&quot;
+    },
+    {
+      &quot;@id&quot;: &quot;_:bnode2&quot;,
+      &quot;@type&quot;: &quot;foaf:Person&quot;,
+      &quot;foaf:homepage&quot;: &quot;http://example.com/eve/&quot;,
+      &quot;foaf:name&quot;: &quot;Eve&quot;
+    },
+    {
+      &quot;@id&quot;: &quot;_:bnode3&quot;,
+      &quot;@type&quot;: &quot;foaf:Person&quot;,
+      &quot;foaf:homepage&quot;: &quot;http://example.com/manu/&quot;,
+      &quot;foaf:name&quot;: &quot;Manu&quot;
+    }
+  ]
+}
+</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">&lt;div class=&quot;vcard&quot;&gt;
+ &lt;a class=&quot;url fn&quot; href=&quot;http://tantek.com/&quot;&gt;Tantek Çelik&lt;/a&gt;
+&lt;/div&gt;
+</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">{
+  &quot;@context&quot;:
+  {
+    &quot;vcard&quot;: &quot;http://microformats.org/profile/hcard#vcard&quot;,
+    &quot;url&quot;: {&quot;@id&quot;: &quot;http://microformats.org/profile/hcard#url&quot;, &quot;@type&quot;: &quot;@id&quot;},
+    &quot;fn&quot;: &quot;http://microformats.org/profile/hcard#fn&quot;
+  },
+  &quot;@id&quot;: &quot;_:bnode1&quot;,
+  &quot;@type&quot;: &quot;vcard&quot;,
+  &quot;url&quot;: &quot;http://tantek.com/&quot;,
+  &quot;fn&quot;: &quot;Tantek Çelik&quot;
+}
+</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">&lt;dl itemscope
+    itemtype=&quot;http://purl.org/vocab/frbr/core#Work&quot;
+    itemid=&quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;&gt;
+ &lt;dt&gt;Title&lt;/dt&gt;
+ &lt;dd&gt;&lt;cite itemprop=&quot;http://purl.org/dc/terms/title&quot;&gt;Just a Geek&lt;/cite&gt;&lt;/dd&gt;
+ &lt;dt&gt;By&lt;/dt&gt;
+ &lt;dd&gt;&lt;span itemprop=&quot;http://purl.org/dc/terms/creator&quot;&gt;Wil Wheaton&lt;/span&gt;&lt;/dd&gt;
+ &lt;dt&gt;Format&lt;/dt&gt;
+ &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
+     itemscope
+     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
+     itemid=&quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;&gt;
+  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/BOOK&quot;&gt;
+  Print
+ &lt;/dd&gt;
+ &lt;dd itemprop=&quot;http://purl.org/vocab/frbr/core#realization&quot;
+     itemscope
+     itemtype=&quot;http://purl.org/vocab/frbr/core#Expression&quot;
+     itemid=&quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;&gt;
+  &lt;link itemprop=&quot;http://purl.org/dc/terms/type&quot; href=&quot;http://purl.oreilly.com/product-types/EBOOK&quot;&gt;
+  Ebook
+ &lt;/dd&gt;
+&lt;/dl&gt;
+</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">[
+  {
+    &quot;@id&quot;: &quot;http://purl.oreilly.com/works/45U8QJGZSQKDH8N&quot;,
+    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Work&quot;,
+    &quot;http://purl.org/dc/terms/title&quot;: &quot;Just a Geek&quot;,
+    &quot;http://purl.org/dc/terms/creator&quot;: &quot;Whil Wheaton&quot;,
+    &quot;http://purl.org/vocab/frbr/core#realization&quot;:
+      [ &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;, &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot; ]
+  },
+  {
+    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596007683.BOOK&quot;,
+    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
+    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/BOOK&quot;
+  },
+  {
+    &quot;@id&quot;: &quot;http://purl.oreilly.com/products/9780596802189.EBOOK&quot;,
+    &quot;@type&quot;: &quot;http://purl.org/vocab/frbr/core#Expression&quot;,
+    &quot;http://purl.org/dc/terms/type&quot;: &quot;http://purl.oreilly.com/product-types/EBOOK&quot;
+  }
+]
+</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">{
+  &quot;@context&quot;:
+  {
+    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,<span class="diff">
+    &quot;sioc&quot;: &quot;http://rdfs.org/sioc/ns#&quot;,
+    &quot;rdfs&quot;: &quot;http://www.w3.org/2000/01/rdf-schema#&quot;</span>
+  },
+  &quot;@type&quot;: &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
+  &quot;foaf:homepage&quot;: &quot;http://manu.sporny.org/&quot;,<span class="diff">
+  &quot;sioc:avatar&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;,
+  &quot;rdfs:comment&quot;: &quot;Likes puppies, unicorns and rainbows.&quot;</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>
[email protected]
+</code>
+keyword,
+like
+so:
+</p>
+<pre class="example">{
+  &quot;@context&quot;:
+  {
+    &quot;foaf&quot;: &quot;http://xmlns.com/foaf/0.1/&quot;,
+    &quot;sioc&quot;: &quot;http://rdfs.org/sioc/ns#&quot;,
+    &quot;rdfs&quot;: &quot;http://www.w3.org/2000/01/rdf-schema#&quot;,
+    <span class="diff">&quot;myvocab&quot;: &quot;http://example.org/myvocab#&quot;</span>
+  },
+  &quot;@type&quot;: &quot;foaf:Person&quot;,
+  &quot;foaf:name&quot;: &quot;Manu Sporny&quot;,
+  &quot;foaf:homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;sioc:avatar&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;,
+  &quot;rdfs:comment&quot;: &quot;Likes puppies, unicorns and rainbows.&quot;
+  <span class="diff">&quot;myvocab:personality&quot;: &quot;friendly&quot;</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
+&amp;
+email
+address
+to
+contact
+for
+further
+information:
+</dt>
+<dd>
+Manu
+Sporny
+&lt;[email protected]&gt;
+</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 @@
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[email protected] screen {
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+        margin: 1.5em 0.5em -1em 1em;
+    }
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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 &quot;Web of Knowledge&quot;. 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/">[email protected]</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">{
+  &quot;name&quot;: &quot;Manu Sporny&quot;,
+  &quot;homepage&quot;: &quot;http://manu.sporny.org/&quot;,
+  &quot;depiction&quot;: &quot;http://twitter.com/account/profile_image/manusporny&quot;
+}</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> i