--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/spec/ED/20110507/diff-20110201.html Sat May 07 17:33:05 2011 -0400
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+
+</style><link href="http://www.w3.org/StyleSheets/TR/w3c-unofficial" rel="stylesheet" type="text/css" charset="utf-8" /><style type='text/css'>
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+</style>
+</head>
+
+
+<body style="display: inherit; ">
+<div class="head">
+<p>
+</p>
+<h1 class="title" id="title">
+JSON-LD
+-
+Linked
+Data
+Expression
+in
+JSON
+</h1>
+<h2 id="subtitle">
+A
+Context-based
+JSON
+Serialization
+for
+Linked
+Data
+</h2>
+<h2 id="unofficial-draft-07-may-2011">
+Unofficial
+Draft
+<del class="diff-old">01
+February
+</del>
+<ins class="diff-chg">07
+May
+</ins>
+2011
+</h2>
+<dl>
+<dt>
+Editor:
+</dt>
+<dd>
+<a href="http://digitalbazaar.com/">
+Manu
+Sporny
+</a>,
+<a href="http://digitalbazaar.com/">
+Digital
+Bazaar,
+Inc.
+</a>
+</dd>
+<dt>
+Authors:
+</dt>
+<dd>
+<a href="http://webbackplane.com/">
+Mark
+Birbeck
+</a>,
+<a href="http://webbackplane.com/">
+Backplane
+Ltd.
+</a>
+</dd>
+<dd>
+<a href="http://digitalbazaar.com/">
+Manu
+Sporny
+</a>,
+<a href="http://digitalbazaar.com/">
+Digital
+Bazaar,
+Inc.
+</a>
+</dd>
+</dl>
+<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>
+Developers
+that
+embed
+structured
+data
+in
+their
+Web
+pages
+can
+choose
+among
+a
+number
+of
+languages
+such
+as
+RDFa
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RDFA-CORE">
+RDFA-CORE
+</a>
+</cite>
+],
+Microformats
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-MICROFORMATS">
+MICROFORMATS
+</a>
+</cite>
+]
+and
+Microdata
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-MICRODATA">
+MICRODATA
+</a>
+</cite>
+].
+Each
+of
+these
+structured
+data
+languages,
+while
+incompatible
+at
+the
+syntax
+level,
+can
+be
+easily
+mapped
+to
+RDF.
+JSON
+has
+proven
+to
+be
+a
+highly
+useful
+object
+serialization
+and
+messaging
+format.
+In
+an
+attempt
+to
+harmonize
+the
+representation
+of
+Linked
+Data
+in
+JSON,
+this
+specification
+outlines
+a
+common
+JSON
+representation
+format
+for
+Linked
+Data
+that
+can
+be
+used
+to
+represent
+objects
+specified
+via
+RDFa,
+Microformats
+and
+Microdata.
+</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="#contributing" class="tocxref">
+<span class="secno">
+1.2
+</span>
+Contributing
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#design-goals-and-rationale" class="tocxref">
+<span class="secno">
+2.
+</span>
+Design
+Goals
+and
+Rationale
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#goals" class="tocxref">
+<span class="secno">
+2.1
+</span>
+Goals
+</a>
+</li>
+<li class="tocline">
+<a href="#map-terms-to-iris" class="tocxref">
+<span class="secno">
+2.2
+</span>
+Map
+Terms
+to
+IRIs
+</a>
+</li>
+<li class="tocline">
+<a href="#the-json-ld-context" class="tocxref">
+<span class="secno">
+2.3
+</span>
+The
+<del class="diff-old">Default
+</del>
+<ins class="diff-chg">JSON-LD
+</ins>
+Context
+</a>
+</li>
+<li class="tocline">
+<a href="#unambiguous-identifiers-for-json" class="tocxref">
+<span class="secno">
+2.4
+</span>
+<ins class="diff-new">Unambiguous
+Identifiers
+for
+JSON
+</ins></a></li><li class="tocline"><a href="#mashing-up-vocabularies" class="tocxref"><span class="secno"><ins class="diff-new">
+2.5
+</ins></span>
+Mashing
+Up
+Vocabularies
+</a>
+</li>
+<li class="tocline">
+<a href="#an-example-of-a-context" class="tocxref">
+<span class="secno">
+<del class="diff-old">2.5
+</del>
+<ins class="diff-chg">2.6
+</ins>
+</span>
+An
+Example
+of
+a
+<del class="diff-old">Default
+</del>
+Context
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#markup-examples" class="tocxref">
+<span class="secno">
+3.
+</span>
+Markup
+Examples
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#rdfa" class="tocxref">
+<span class="secno">
+3.1
+</span>
+RDFa
+</a>
+</li>
+<li class="tocline">
+<a href="#microformats" class="tocxref">
+<span class="secno">
+3.2
+</span>
+Microformats
+</a>
+</li>
+<li class="tocline">
+<a href="#microdata" class="tocxref">
+<span class="secno">
+3.3
+</span>
+Microdata
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#the-json-ld-processing-algorithm" class="tocxref">
+<span class="secno">
+4.
+</span>
+The
+JSON-LD
+Processing
+Algorithm
+</a>
+</li>
+<li class="tocline">
+<a href="#markup-of-rdf-concepts" class="tocxref">
+<span class="secno">
+5.
+</span>
+Markup
+of
+RDF
+Concepts
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#iris" class="tocxref">
+<span class="secno">
+5.1
+</span>
+IRIs
+</a>
+</li>
+<li class="tocline">
+<a href="#identifying-the-subject" class="tocxref">
+<span class="secno">
+5.2
+</span>
+Identifying
+the
+Subject
+</a>
+</li>
+<li class="tocline">
+<a href="#specifying-the-type" class="tocxref">
+<span class="secno">
+5.3
+</span>
+Specifying
+the
+Type
+</a>
+</li>
+<li class="tocline">
+<a href="#plain-literals" class="tocxref">
+<span class="secno">
+5.4
+</span>
+Plain
+Literals
+</a>
+</li>
+<li class="tocline">
+<a href="#language-specification-in-plain-literals" class="tocxref">
+<span class="secno">
+5.5
+</span>
+Language
+Specification
+in
+Plain
+Literals
+</a>
+</li>
+<li class="tocline">
+<a href="#typed-literals" class="tocxref">
+<span class="secno">
+5.6
+</span>
+Typed
+Literals
+</a>
+</li>
+<li class="tocline">
+<a href="#multiple-objects-for-a-single-property" class="tocxref">
+<span class="secno">
+5.7
+</span>
+Multiple
+Objects
+for
+a
+Single
+Property
+</a>
+</li>
+<li class="tocline">
+<a href="#multiple-typed-literals-for-a-single-property" class="tocxref">
+<span class="secno">
+5.8
+</span>
+Multiple
+Typed
+Literals
+for
+a
+Single
+Property
+</a>
+</li>
+<li class="tocline">
+<a href="#blank-nodes" class="tocxref">
+<span class="secno">
+5.9
+</span>
+Blank
+Nodes
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#advanced-features" class="tocxref">
+<span class="secno">
+6.
+</span>
+Advanced
+Features
+</a>
+<ul class="toc">
+<li class="tocline">
+<del class="diff-old">6.1
+Escape
+Character
+</del>
+<a href="#automatic-typing" class="tocxref">
+<span class="secno">
+<del class="diff-old">6.2
+</del>
+<ins class="diff-chg">6.1
+</ins>
+</span>
+Automatic
+Typing
+</a>
+</li>
+<li class="tocline">
+<a href="#type-coercion" class="tocxref">
+<span class="secno">
+<del class="diff-old">6.3
+</del>
+<ins class="diff-chg">6.2
+</ins>
+</span>
+Type
+Coercion
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#best-practices" class="tocxref">
+<span class="secno">
+7.
+</span>
+Best
+Practices
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#javascript" class="tocxref">
+<span class="secno">
+7.1
+</span>
+JavaScript
+</a>
+</li>
+<li class="tocline">
+<a href="#schema-less-databases" class="tocxref">
+<span class="secno">
+7.2
+</span>
+Schema-less
+Databases
+</a>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#advanced-concepts" class="tocxref">
+<span class="secno">
+8.
+</span>
+Advanced
+Concepts
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#vocabulary-profiles" class="tocxref">
+<span class="secno">
+8.1
+</span>
+Vocabulary
+Profiles
+</a>
+</li>
+<li class="tocline">
+<a href="#disjoint-graphs" class="tocxref">
+<span class="secno">
+8.2
+</span>
+Disjoint
+Graphs
+</a>
+</li>
+<li class="tocline">
+<a href="#the-json-ld-api" class="tocxref">
+<span class="secno">
+8.3
+</span>
+The
+JSON-LD
+API
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#methods" class="tocxref">
+<span class="secno">
+8.3.1
+</span>
+Methods
+</a>
+</li>
+<li class="tocline">
+<a href="#methods-1" class="tocxref">
+<span class="secno">
+8.3.2
+</span>
+Methods
+</a>
+</li>
+<li class="tocline">
+<a href="#methods-2" class="tocxref">
+<span class="secno">
+8.3.3
+</span>
+Methods
+</a>
+</li>
+</ul>
+</li>
+</ul>
+</li>
+<li class="tocline">
+<a href="#the-default-context" class="tocxref">
+<span class="secno">
+A.
+</span>
+<ins class="diff-new">The
+Default
+Context
+</ins></a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno"><ins class="diff-new">
+B.
+</ins></span>
+Acknowledgements
+</a>
+</li>
+<li class="tocline">
+<a href="#references" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.
+</del>
+<ins class="diff-chg">C.
+</ins>
+</span>
+References
+</a>
+<ul class="toc">
+<li class="tocline">
+<a href="#normative-references" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.1
+</del>
+<ins class="diff-chg">C.1
+</ins>
+</span>
+Normative
+references
+</a>
+</li>
+<li class="tocline">
+<a href="#informative-references" class="tocxref">
+<span class="secno">
+<del class="diff-old">B.2
+</del>
+<ins class="diff-chg">C.2
+</ins>
+</span>
+Informative
+references
+</a>
+</li>
+</ul>
+</li>
+</ul>
+</div>
+<div id="introduction" class="section">
+<h2>
+<span class="secno">
+1.
+</span>
+Introduction
+</h2>
+<del class="diff-old">Write
+the
+introduction
+once
+all
+of
+the
+technical
+details
+are
+hammered
+out.
+Explain
+why
+</del>
+JSON-LD
+is
+designed
+as
+a
+light-weight
+<del class="diff-old">mechanism
+</del>
+<ins class="diff-chg">syntax
+that
+can
+be
+used
+</ins>
+to
+express
+<del class="diff-old">RDFa,
+Microformats
+and
+Microdata.
+</del>
+<ins class="diff-chg">Linked
+Data.
+</ins>
+It
+is
+primarily
+intended
+<del class="diff-old">as
+</del>
+<ins class="diff-chg">to
+be
+</ins>
+a
+way
+to
+express
+Linked
+Data
+in
+Javascript
+<del class="diff-old">environments
+as
+well
+as
+a
+way
+to
+pass
+Linked
+Data
+to
+</del>
+and
+<del class="diff-old">from
+</del>
+<ins class="diff-chg">other
+Web-based
+programming
+environments.
+It
+is
+also
+useful
+when
+building
+interoperable
+</ins>
+Web
+<del class="diff-old">services.
+</del>
+<ins class="diff-chg">Services
+and
+when
+storing
+Linked
+Data
+in
+JSON-based
+document
+storage
+engines.
+</ins>
+It
+is
+<ins class="diff-new">practical
+and
+</ins>
+designed
+to
+be
+as
+simple
+as
+possible,
+utilizing
+the
+large
+number
+of
+JSON
+parsers
+<del class="diff-old">(and
+understanding)
+</del>
+<ins class="diff-chg">and
+existing
+code
+</ins>
+that
+is
+<del class="diff-old">out
+there
+already.
+</del>
+<ins class="diff-chg">in
+use
+today.
+</ins>
+It
+is
+designed
+to
+be
+able
+to
+express
+key-value
+pairs,
+RDF
+data,
+Microformats
+data,
+and
+<del class="diff-old">Microdata
+(that
+</del>
+<ins class="diff-chg">Microdata.
+That
+</ins>
+is,
+<ins class="diff-new">it
+supports
+</ins>
+every
+<ins class="diff-new">major
+Web-based
+structured
+</ins>
+data
+model
+<del class="diff-old">currently
+</del>
+in
+<del class="diff-old">use)
+using
+one
+unified
+format.
+</del>
+<ins class="diff-chg">use
+today.
+</ins>
+It
+does
+not
+require
+anyone
+to
+change
+their
+JSON,
+but
+easily
+add
+meaning
+by
+adding
+context
+in
+a
+way
+that
+is
+<del class="diff-old">out-of-band
+-
+it
+</del>
+<ins class="diff-chg">out-of-band.
+The
+syntax
+</ins>
+is
+designed
+to
+not
+disturb
+already
+deployed
+systems
+running
+on
+JSON,
+but
+provide
+a
+smooth
+migration
+path
+from
+JSON
+to
+JSON
+with
+added
+semantics.
+Finally,
+the
+format
+is
+intended
+to
+be
+fast
+to
+parse,
+fast
+to
+generate,
+stream-based
+and
+document-based
+processing
+compatible,
+and
+require
+a
+<del class="diff-old">tiny
+</del>
+<ins class="diff-chg">very
+small
+</ins>
+memory
+footprint
+in
+order
+to
+operate.
+<p>
+</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
+JSON
+for
+Linked
+data.
+The
+document
+is
+primarily
+intended
+for
+the
+following
+audiences:
+</p>
+<ul>
+<li>
+Web
+developers
+that
+want
+to
+understand
+the
+design
+decisions
+and
+language
+syntax
+for
+JSON-LD.
+</li>
+<li>
+Software
+developers
+that
+want
+to
+encode
+Microformats,
+RDFa,
+or
+Microdata
+in
+a
+way
+that
+is
+cross-language
+compatible
+via
+JSON.
+</li>
+<li>
+Software
+developers
+that
+want
+to
+write
+processors
+for
+JSON-LD.
+</li>
+</ul>
+<p>
+To
+understand
+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>
+]
+and
+[
+<cite>
+<a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">
+RDF-CONCEPTS
+</a>
+</cite>
+].
+</p>
+</div>
+<div id="contributing" class="section">
+<h3>
+<span class="secno">
+1.2
+</span>
+Contributing
+</h3>
+<p>
+There
+are
+a
+number
+of
+ways
+that
+one
+may
+participate
+in
+the
+development
+of
+this
+specification:
+</p>
+<ul>
+<li>
+All
+comments
+and
+discussion
+takes
+place
+on
+the
+public
+mailing
+list:
+<del class="diff-old">json-ld@googlegroups.com
+</del>
+<a href="http://lists.w3.org/Archives/Public/public-linked-json/">
+<ins class="diff-chg">public-linked-json@w3.org
+</ins>
+</a>
+</li>
+<li>
+Specification
+bugs
+and
+issues
+should
+be
+reported
+in
+the
+<a href="http://github.com/digitalbazaar/json-ld/issues">
+issue
+tracker
+</a>.
+</li>
+<li>
+<a href="http://github.com/digitalbazaar/json-ld">
+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 id="design-goals-and-rationale" class="section">
+<h2>
+<span class="secno">
+2.
+</span>
+Design
+Goals
+and
+Rationale
+</h2>
+<p>
+The
+following
+section
+outlines
+the
+design
+goals
+and
+rationale
+behind
+the
+JSON-LD
+markup
+language.
+</p>
+<div id="goals" class="section">
+<h3>
+<span class="secno">
+2.1
+</span>
+Goals
+</h3>
+<p>
+A
+number
+of
+design
+considerations
+were
+explored
+during
+the
+creation
+of
+this
+markup
+language:
+</p>
+<dl>
+<dt>
+Simplicity
+</dt>
+<dd>
+Developers
+don't
+need
+to
+know
+RDF
+in
+order
+to
+use
+the
+basic
+functionality
+provided
+by
+JSON-LD.
+</dd>
+<dt>
+Compatibility
+</dt>
+<dd>
+The
+JSON-LD
+markup
+should
+be
+100%
+compatible
+with
+JSON.
+</dd>
+<dt>
+Expressiveness
+</dt>
+<dd>
+All
+major
+RDF
+concepts
+must
+be
+expressible
+via
+the
+JSON-LD
+syntax.
+</dd>
+<dt>
+Terseness
+</dt>
+<dd>
+The
+JSON-LD
+syntax
+must
+be
+very
+terse
+and
+human
+readable.
+</dd>
+<dt>
+Zero
+<del class="diff-old">Edits
+</del>
+<ins class="diff-chg">Edits,
+most
+of
+the
+time
+</ins>
+</dt>
+<dd>
+JSON-LD
+provides
+a
+mechanism
+that
+allows
+developers
+to
+specify
+context
+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
+in
+a
+way
+that
+is
+not
+disruptive
+to
+their
+day-to-day
+operations
+and
+is
+transparent
+to
+their
+current
+customers.
+<ins class="diff-new">At
+times,
+mapping
+JSON
+to
+RDF
+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
+we
+strive
+for
+Zero
+Edits,
+it
+was
+not
+always
+possible
+without
+adding
+great
+complexity
+to
+the
+language.
+</ins>
+</dd>
+<dt>
+Streaming
+</dt>
+<dd>
+The
+format
+supports
+both
+document-based
+and
+stream-based
+processing.
+</dd>
+</dl>
+</div>
+<div id="map-terms-to-iris" class="section">
+<h3>
+<span class="secno">
+2.2
+</span>
+Map
+Terms
+to
+IRIs
+</h3>
+<p>
+Establishing
+a
+mechanism
+to
+map
+JSON
+values
+to
+IRIs
+will
+help
+in
+the
+mapping
+of
+JSON
+objects
+to
+RDF.
+This
+does
+not
+mean
+that
+JSON-LD
+must
+be
+restrictive
+in
+declaring
+a
+set
+of
+terms,
+rather,
+experimentation
+and
+innovation
+should
+be
+supported
+as
+part
+of
+the
+core
+design
+of
+JSON-LD.
+There
+are,
+however,
+a
+number
+of
+very
+small
+design
+<del class="diff-old">criterial
+</del>
+<ins class="diff-chg">criteria
+</ins>
+that
+can
+ensure
+that
+developers
+will
+generate
+good
+RDF
+data
+that
+will
+create
+value
+for
+the
+greater
+semantic
+web
+community
+and
+JSON/REST-based
+Web
+Services
+community.
+</p>
+<p>
+We
+will
+be
+using
+the
+following
+JSON
+object
+as
+the
+example
+for
+this
+section:
+</p>
+<pre class="example">
+{
+ "a": "Person",
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+<ins class="diff-new"> "avatar": "http://twitter.com/account/profile_image/manusporny"
+</ins>
+}
+</pre>
+</div>
+<div id="the-json-ld-context" class="section">
+<h3>
+<span class="secno">
+2.3
+</span>
+The
+<del class="diff-old">Default
+</del>
+<ins class="diff-chg">JSON-LD
+</ins>
+Context
+</h3>
+<p>
+A
+<del class="diff-old">default
+</del>
+context
+is
+used
+in
+RDFa
+to
+allow
+developers
+to
+use
+<del class="diff-old">keywords
+as
+</del>
+aliases
+for
+IRIs.
+<del class="diff-old">So,
+for
+instance,
+the
+keyword
+name
+above
+could
+refer
+to
+the
+IRI
+http://xmlns.com/foaf/0.1/name
+.
+</del>
+The
+semantic
+web,
+just
+like
+the
+document-based
+web,
+uses
+IRIs
+for
+unambiguous
+identification.
+The
+idea
+is
+that
+these
+terms
+mean
+something,
+which
+you
+will
+eventually
+want
+to
+query.
+The
+semantic
+web
+specifies
+this
+via
+<em>
+Vocabulary
+Documents
+</em>.
+The
+IRI
+<em>
+http://xmlns.com/foaf/0.1/
+</em>
+specifies
+a
+Vocabulary
+Document,
+and
+<strong>
+name
+</strong>
+is
+a
+term
+in
+that
+vocabulary.
+<del class="diff-old">Paste
+</del>
+<ins class="diff-chg">Join
+</ins>
+the
+two
+items
+together
+and
+you
+have
+an
+unambiguous
+identifier
+for
+a
+<ins class="diff-new">vocabulary
+</ins>
+term.
+<ins class="diff-new">The
+Compact
+URI
+Expression,
+or
+short-form,
+is
+</ins><code><ins class="diff-new">
+foaf:name
+</ins></code><ins class="diff-new">
+and
+the
+expanded-form
+is
+</ins><code><ins class="diff-new">
+http://xmlns.com/foaf/0.1/name
+</ins></code>.<ins class="diff-new">
+This
+vocabulary
+term
+identifies
+the
+given
+name
+for
+something,
+for
+example
+-
+a
+person's
+name.
+</ins>
+</p>
+<p>
+Developers,
+and
+machines,
+would
+be
+able
+to
+use
+this
+IRI
+(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
+WordNet
+today
+to
+see
+the
+<a href="http://wordnetweb.princeton.edu/perl/webwn?s=definition">
+definition
+</a>
+of
+words
+in
+the
+English
+language.
+Machines
+need
+the
+same
+sort
+of
+dictionary
+of
+terms,
+and
+URIs
+provide
+a
+way
+to
+ensure
+that
+these
+terms
+are
+unambiguous.
+</p>
+<p>
+<del class="diff-old">Non-prefixed
+terms
+should
+have
+term
+mappings
+declared
+in
+the
+default
+</del>
+<ins class="diff-chg">The
+</ins>
+context
+<del class="diff-old">so
+</del>
+<ins class="diff-chg">provides
+a
+collection
+of
+vocabulary
+terms
+</ins>
+that
+<del class="diff-old">they
+may
+</del>
+<ins class="diff-chg">can
+</ins>
+be
+<del class="diff-old">expanded
+later.
+</del>
+<ins class="diff-chg">used
+for
+a
+JSON
+object.
+</ins>
+</p>
+</div>
+<div id="unambiguous-identifiers-for-json" class="section">
+<h3>
+<span class="secno">
+<ins class="diff-new">2.4
+</ins></span><ins class="diff-new">
+Unambiguous
+Identifiers
+for
+JSON
+</ins></h3>
+<p>
+If
+a
+set
+of
+terms,
+like
+<strong>
+Person
+</strong>,
+<strong>
+name
+</strong>,
+and
+<strong>
+homepage
+</strong>,
+are
+<del class="diff-old">pre-defined
+</del>
+<ins class="diff-chg">defined
+</ins>
+in
+<del class="diff-old">the
+default
+</del>
+<ins class="diff-chg">a
+</ins>
+context,
+and
+that
+context
+is
+used
+to
+resolve
+the
+names
+in
+JSON
+objects,
+machines
+could
+automatically
+expand
+the
+terms
+to
+something
+meaningful
+and
+unambiguous,
+like
+this:
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "",
+</del>
+<ins class="diff-chg"> "<span class="diff">http://www.w3.org/1999/02/22-rdf-syntax-ns#type</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+</ins>
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+<del class="diff-old"> ""
+</del>
+<ins class="diff-chg"> "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>": "http://manu.sporny.org"
+ "<span class="diff">http://rdfs.org/sioc/ns#avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+</ins>
+}
+</pre>
+<del class="diff-old">In
+order
+to
+differentiate
+between
+plain
+text
+and
+IRIs,
+the
+<
+>
+are
+used
+around
+IRIs.
+</del>
+<p>
+Doing
+this
+would
+mean
+that
+JSON
+would
+start
+to
+become
+unambiguously
+machine-readable,
+play
+well
+with
+the
+semantic
+web,
+and
+basic
+markup
+wouldn't
+be
+that
+much
+more
+complex
+than
+basic
+JSON
+markup.
+A
+win,
+all
+around.
+</p>
+</div>
+<div id="mashing-up-vocabularies" class="section">
+<h3>
+<span class="secno">
+<del class="diff-old">2.4
+</del>
+<ins class="diff-chg">2.5
+</ins>
+</span>
+Mashing
+Up
+Vocabularies
+</h3>
+<p>
+Developers
+would
+also
+benefit
+by
+allowing
+other
+vocabularies
+to
+be
+used
+automatically
+with
+their
+JSON
+API.
+There
+are
+over
+200
+Vocabulary
+Documents
+that
+are
+available
+for
+use
+on
+the
+Web
+today.
+Some
+of
+these
+vocabularies
+are:
+</p>
+<ul>
+<li>
+<ins class="diff-new">RDF
+-
+for
+describing
+information
+about
+objects
+on
+the
+semantic
+web.
+</ins></li><li><ins class="diff-new">
+RDFS
+-
+for
+expressing
+things
+like
+labels
+and
+comments.
+</ins></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>
+<del class="diff-old">A
+JSON-LD
+Web
+Service
+could
+define
+</del>
+<ins class="diff-chg">Since
+</ins>
+these
+<del class="diff-old">as
+prefix
+es
+</del>
+<ins class="diff-chg">vocabularies
+are
+very
+popular,
+they
+are
+pre-defined
+</ins>
+in
+<del class="diff-old">their
+</del>
+<ins class="diff-chg">something
+called
+the
+</ins><a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">
+default
+context
+<del class="diff-old">beside
+the
+terms
+</del>
+</a>,
+<ins class="diff-chg">which
+is
+a
+set
+of
+vocabulary
+prefixes
+</ins>
+that
+are
+<del class="diff-old">already
+defined.
+Using
+</del>
+<ins class="diff-chg">pre-loaded
+in
+all
+JSON-LD
+processors.
+The
+contents
+of
+the
+</ins><a class="tref internalDFN" title="default_context" href="#dfn-default_context-1"><ins class="diff-chg">
+default
+context
+</ins></a><ins class="diff-chg">
+are
+provided
+later
+in
+</ins>
+this
+<del class="diff-old">feature,
+</del>
+<ins class="diff-chg">document.
+Using
+the
+</ins><a class="tref internalDFN" title="default_context" href="#dfn-default_context-1"><ins class="diff-chg">
+default
+context
+</ins></a><ins class="diff-chg">
+allows
+</ins>
+developers
+<del class="diff-old">could
+also
+</del>
+<ins class="diff-chg">to
+</ins>
+express
+<del class="diff-old">markup
+</del>
+<ins class="diff-chg">data
+unambiguously,
+</ins>
+like
+<del class="diff-old">this:
+</del>
+<ins class="diff-chg">so:
+</ins>
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "",
+</del>
+<ins class="diff-chg"> "<span class="diff">rdf:type</span>": "<span class="diff">foaf:Person</span>",
+</ins>
+ "<span class="diff">foaf:name</span>": "Manu Sporny",
+<del class="diff-old"> ",
+ "sioc:avatar": "<http://twitter.com/account/profile_image/manusporny>"
+</del>
+<ins class="diff-chg"> "<span class="diff">foaf:homepage</span>": "http://manu.sporny.org/",
+ "<span class="diff">sioc:avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+</ins>
+}
+</pre>
+<p>
+Developers
+can
+also
+specify
+their
+own
+Vocabulary
+documents
+by
+modifying
+the
+default
+context
+in-line
+using
+the
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">character,
+</del>
+<ins class="diff-chg">keyword,
+</ins>
+like
+so:
+</p>
+<pre class="example">
+{
+<del class="diff-old"> ,
+ "a": "<foaf:Person>",
+</del>
+ <span class="diff">"@context": { "myvocab": "http://example.org/myvocab#" }</span>,
+<ins class="diff-chg"> "a": "foaf:Person",
+</ins>
+ "foaf:name": "Manu Sporny",
+<del class="diff-old"> "foaf:homepage": "<http://manu.sporny.org/>",
+ "sioc:avatar": "<http://twitter.com/account/profile_image/manusporny>",
+ "myvocab:credits": 500
+</del>
+<ins class="diff-chg"> "foaf:homepage": "http://manu.sporny.org/",
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny"<span class="diff">,
+ "myvocab:personality": "friendly"</span>
+</ins>
+}
+</pre>
+<p>
+<del class="diff-old">Think
+of
+the
+</del>
+<ins class="diff-chg">The
+</ins>
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">character
+as
+a
+"
+hash
+table",
+which
+maps
+</del>
+<ins class="diff-chg">keyword
+is
+used
+to
+change
+how
+the
+JSON-LD
+processor
+evaluates
+key-value
+pairs.
+In
+this
+case,
+it
+was
+used
+to
+map
+</ins>
+one
+string
+<ins class="diff-new">('myvocab')
+</ins>
+to
+another
+<del class="diff-old">string.
+</del>
+<ins class="diff-chg">string,
+which
+is
+interpreted
+as
+a
+IRI.
+</ins>
+In
+the
+example
+above,
+the
+<code>
+myvocab
+</code>
+string
+is
+replaced
+with
+"
+<code>
+http://example.org/myvocab#
+</code>
+"
+when
+it
+is
+<del class="diff-old">detected
+above.
+</del>
+<ins class="diff-chg">detected.
+</ins>
+In
+the
+example
+above,
+"
+<code>
+<del class="diff-old">myvocab:credits
+</del>
+<ins class="diff-chg">myvocab:personality
+</ins>
+</code>
+"
+would
+expand
+to
+"
+<code>
+<del class="diff-old">http://example.org/myvocab#credits
+</del>
+<ins class="diff-chg">http://example.org/myvocab#personality
+</ins>
+</code>
+".
+</p>
+<p>
+This
+mechanism
+is
+a
+short-hand
+for
+RDF,
+<ins class="diff-new">called
+a
+CURIE,
+</ins>
+and
+<del class="diff-old">if
+defined,
+will
+give
+</del>
+<ins class="diff-chg">provides
+</ins>
+developers
+an
+unambiguous
+way
+to
+map
+any
+JSON
+value
+to
+RDF.
+</p>
+<p>
+</p>
+</div>
+<div id="an-example-of-a-context" class="section">
+<h3>
+<span class="secno">
+<del class="diff-old">2.5
+</del>
+<ins class="diff-chg">2.6
+</ins>
+</span>
+An
+Example
+of
+a
+<del class="diff-old">Default
+</del>
+Context
+</h3>
+<p>
+JSON-LD
+strives
+to
+ensure
+that
+developers
+don't
+have
+to
+change
+the
+JSON
+that
+is
+going
+into
+and
+being
+returned
+from
+their
+Web
+applications.
+A
+JSON-LD
+aware
+Web
+Service
+<em class="rfc2119" title="may">
+may
+</em>
+define
+a
+<del class="diff-old">default
+</del>
+<ins class="diff-chg">known
+</ins>
+context.
+For
+example,
+the
+following
+default
+context
+could
+apply
+to
+all
+incoming
+Web
+Service
+calls
+previously
+accepting
+only
+JSON
+data:
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "#":
+</del>
+<ins class="diff-chg"> "@context":
+</ins>
+ {
+<del class="diff-old"> "#vocab": "http://example.org/default-vocab#",
+ "#base": "http://example.org/baseurl/",
+</del>
+<ins class="diff-chg"> "@vocab": "http://example.org/default-vocab#",
+ "@base": "http://example.org/baseurl/",
+</ins>
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "dc": "http://purl.org/dc/terms/",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "cc": "http://creativecommons.org/ns#",
+ "geo": "http://www.w3.org/2003/01/geo/wgs84_pos#",
+ "vcard": "http://www.w3.org/2006/vcard/ns#",
+ "cal": "http://www.w3.org/2002/12/cal/ical#",
+ "doap": "http://usefulinc.com/ns/doap#",
+ "Person": "http://xmlns.com/foaf/0.1/Person",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage"
+<ins class="diff-new"> "@coerce":
+ {
+ "xsd:anyURI": ["foaf:homepage", "foaf:member"],
+ "xsd:integer": "foaf:age"
+ }
+</ins>
+ }
+}
+</pre>
+<p>
+The
+<code>
+<del class="diff-old">#vocab
+</del>
+<ins class="diff-chg">@vocab
+</ins>
+</code>
+string
+is
+a
+special
+keyword
+that
+states
+that
+any
+term
+that
+doesn't
+resolve
+to
+a
+term
+or
+a
+prefix
+should
+be
+appended
+to
+the
+<code>
+<del class="diff-old">#vocab
+</del>
+<ins class="diff-chg">@vocab
+</ins>
+</code>
+IRI.
+This
+is
+done
+to
+ensure
+that
+terms
+can
+be
+transformed
+to
+an
+IRI
+at
+all
+times.
+</p>
+<p>
+The
+<code>
+<del class="diff-old">#base
+</del>
+<ins class="diff-chg">@base
+</ins>
+</code>
+string
+is
+a
+special
+keyword
+that
+states
+that
+any
+relative
+IRI
+<em class="rfc2119" title="must">
+must
+</em>
+be
+appended
+to
+the
+string
+specified
+by
+<code>
+<del class="diff-old">#base
+</del>
+<ins class="diff-chg">@base
+</ins></code>.</p><p><ins class="diff-chg">
+The
+</ins><code><ins class="diff-chg">
+@coerce
+</ins></code><ins class="diff-chg">
+keyword
+is
+used
+to
+specify
+type
+coersion
+rules
+for
+the
+data.
+For
+each
+key
+in
+the
+map,
+the
+key
+is
+the
+type
+to
+be
+coerced
+to
+and
+the
+value
+is
+the
+vocabulary
+term
+to
+be
+coerced.
+Type
+coersion
+for
+the
+key
+</ins><code><ins class="diff-chg">
+xsd:anyURI
+</ins></code><ins class="diff-chg">
+asserts
+that
+all
+vocabulary
+terms
+listed
+should
+undergo
+coercion
+to
+an
+IRI,
+including
+</ins><code><ins class="diff-chg">
+@base
+</ins></code><ins class="diff-chg">
+processing
+for
+relative
+IRIs
+and
+CURIE
+processing
+for
+compact
+URI
+Expressions
+like
+</ins><code><ins class="diff-chg">
+foaf:homepage
+</ins>
+</code>.
+</p>
+</div>
+</div>
+<div id="markup-examples" class="section">
+<h2>
+<span class="secno">
+3.
+</span>
+Markup
+Examples
+</h2>
+<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
+RDFa,
+Microformats,
+and
+Microdata.
+These
+sections
+are
+merely
+provided
+as
+proof
+that
+JSON-LD
+is
+very
+flexible
+in
+what
+it
+can
+express
+across
+different
+Linked
+Data
+approaches.
+</p>
+<div id="rdfa" class="section">
+<h3>
+<span class="secno">
+3.1
+</span>
+RDFa
+</h3>
+<p>
+The
+following
+example
+describes
+three
+people
+with
+their
+respective
+names
+and
+homepages.
+</p>
+<pre class="example">
+<div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>>
+ <ul>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name" </span>>Bob</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name" </span>>Eve</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name" </span>>Manu</a>
+ </li>
+ </ul>
+</div>
+</pre>
+<p>
+An
+example
+JSON-LD
+implementation
+is
+described
+below,
+however,
+there
+are
+other
+ways
+to
+mark-up
+this
+information
+such
+that
+the
+context
+is
+not
+repeated.
+</p>
+<pre class="example">
+[
+ {
+<del class="diff-old"> "#": { "foaf": "http://xmlns.com/foaf/0.1/" },
+</del>
+ "@": "_:bnode1",
+ "a": "foaf:Person",
+<del class="diff-old"> "foaf:homepage": "<http://example.com/bob/>",
+</del>
+<ins class="diff-chg"> "foaf:homepage": "http://example.com/bob/",
+</ins>
+ "foaf:name": "Bob"
+ },
+ {
+<del class="diff-old"> "#": { "foaf": "http://xmlns.com/foaf/0.1/" },
+</del>
+ "@": "_:bnode2",
+ "a": "foaf:Person",
+<del class="diff-old"> "foaf:homepage": "<http://example.com/eve/>",
+</del>
+<ins class="diff-chg"> "foaf:homepage": "http://example.com/eve/",
+</ins>
+ "foaf:name": "Eve"
+ },
+ {
+<del class="diff-old"> "#": { "foaf": "http://xmlns.com/foaf/0.1/" },
+</del>
+ "@": "_:bnode3",
+ "a": "foaf:Person",
+<del class="diff-old"> "foaf:homepage": "<http://example.com/manu/>",
+</del>
+<ins class="diff-chg"> "foaf:homepage": "http://example.com/manu/",
+</ins>
+ "foaf:name": "Manu"
+ }
+]
+</pre>
+</div>
+<div id="microformats" class="section">
+<h3>
+<span class="secno">
+3.2
+</span>
+Microformats
+</h3>
+<p>
+The
+following
+example
+uses
+a
+simple
+Microformats
+hCard
+example
+to
+express
+how
+the
+Microformat
+is
+represented
+in
+JSON-LD.
+</p>
+<pre class="example">
+<div class="vcard">
+<del class="diff-old"> <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</del>
+<ins class="diff-chg"> <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</ins>
+</div>
+</pre>
+<p>
+The
+representation
+of
+the
+hCard
+expresses
+the
+Microformat
+terms
+in
+the
+context
+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">
+{
+<del class="diff-old"> "#":
+</del>
+<ins class="diff-chg"> "@context":
+</ins>
+ {
+<del class="diff-old"> "vcard": "http://microformats.org/profile/hcard#vcard"
+ "url": "http://microformats.org/profile/hcard#url"
+ "fn": "http://microformats.org/profile/hcard#fn"
+</del>
+<ins class="diff-chg"> "vcard": "http://microformats.org/profile/hcard#vcard",
+ "url": "http://microformats.org/profile/hcard#url",
+ "fn": "http://microformats.org/profile/hcard#fn",
+ "@coerce": { "xsd:anyURI": "url" }
+</ins>
+ },
+ "@": "_:bnode1",
+ "a": "vcard",
+<del class="diff-old"> "url": "<http://tantek.com/>",
+ "fn": "Tantek Çelik"
+</del>
+<ins class="diff-chg"> "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+</ins>
+}
+</pre>
+</div>
+<div id="microdata" class="section">
+<h3>
+<span class="secno">
+3.3
+</span>
+Microdata
+</h3>
+<p>
+The
+Microdata
+example
+below
+expresses
+book
+information
+as
+a
+Microdata
+Work
+item.
+</p>
+<pre class="example">
+<dl itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Work"
+ itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N">
+ <dt>Title</dt>
+ <dd><cite itemprop="http://purl.org/dc/terms/title">Just a Geek</cite></dd>
+ <dt>By</dt>
+ <dd><span itemprop="http://purl.org/dc/terms/creator">Wil Wheaton</span></dd>
+ <dt>Format</dt>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596007683.BOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK">
+ Print
+ </dd>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596802189.EBOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK">
+ Ebook
+ </dd>
+</dl>
+</pre>
+<p>
+Note
+that
+the
+JSON-LD
+representation
+of
+the
+Microdata
+information
+stays
+true
+to
+the
+desires
+of
+the
+Microdata
+community
+to
+avoid
+contexts
+and
+instead
+refer
+to
+items
+by
+their
+full
+IRI.
+</p>
+<pre class="example">
+[
+ {
+<del class="diff-old"> "@": "<http://purl.oreilly.com/works/45U8QJGZSQKDH8N>",
+</del>
+<ins class="diff-chg"> "@": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
+</ins>
+ "a": "http://purl.org/vocab/frbr/core#Work",
+ "http://purl.org/dc/terms/title": "Just a Geek",
+ "http://purl.org/dc/terms/creator": "Whil Wheaton",
+ "http://purl.org/vocab/frbr/core#realization":
+<del class="diff-old"> ["<http://purl.oreilly.com/products/9780596007683.BOOK>", "<http://purl.oreilly.com/products/9780596802189.EBOOK>"]
+</del>
+<ins class="diff-chg"> ["http://purl.oreilly.com/products/9780596007683.BOOK", "http://purl.oreilly.com/products/9780596802189.EBOOK"]
+</ins>
+ },
+ {
+<del class="diff-old"> "@": "<http://purl.oreilly.com/products/9780596007683.BOOK>",
+ "a": "<http://purl.org/vocab/frbr/core#Expression>",
+ "http://purl.org/dc/terms/type": "<http://purl.oreilly.com/product-types/BOOK>"
+</del>
+<ins class="diff-chg"> "@": "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "a": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
+</ins>
+ },
+ {
+<del class="diff-old"> "@": "<http://purl.oreilly.com/products/9780596802189.EBOOK>",
+</del>
+<ins class="diff-chg"> "@": "http://purl.oreilly.com/products/9780596802189.EBOOK",
+</ins>
+ "a": "http://purl.org/vocab/frbr/core#Expression",
+<del class="diff-old"> "http://purl.org/dc/terms/type": "<http://purl.oreilly.com/product-types/EBOOK>"
+</del>
+<ins class="diff-chg"> "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
+</ins>
+ }
+]
+</pre>
+</div>
+</div>
+<div id="the-json-ld-processing-algorithm" class="section">
+<h2>
+<span class="secno">
+4.
+</span>
+The
+JSON-LD
+Processing
+Algorithm
+</h2>
+<p>
+The
+processing
+algorithm
+described
+in
+this
+section
+is
+provided
+in
+order
+to
+demonstrate
+how
+one
+might
+implement
+a
+JSON-LD
+processor.
+Conformant
+implementations
+are
+only
+required
+to
+produce
+the
+same
+type
+and
+number
+of
+triples
+during
+the
+output
+process
+and
+are
+not
+required
+to
+implement
+the
+algorithm
+exactly
+as
+described.
+</p>
+<p class="issue">
+The
+Processing
+Algorithm
+is
+a
+work
+in
+progress,
+there
+are
+still
+major
+bugs
+in
+the
+algorithm
+and
+it's
+difficult
+to
+follow.
+It's
+provided
+only
+to
+very
+early
+implementers
+to
+give
+them
+an
+idea
+of
+how
+to
+implement
+a
+processor.
+</p>
+<h4 id="processing-algorithm-terms">
+Processing
+Algorithm
+Terms
+</h4>
+<ul>
+<li>
+<dfn title="default_context" id="dfn-default_context">
+default
+context
+</dfn>
+-
+a
+context
+that
+is
+specified
+to
+the
+JSON-LD
+processing
+algorithm
+before
+processing
+begins.
+</li>
+<li>
+<dfn title="default_graph" id="dfn-default_graph">
+default
+graph
+</dfn>
+-
+the
+destination
+graph
+for
+all
+triples
+generated
+by
+JSON-LD
+markup.
+</li>
+<li>
+<dfn title="active_subject" id="dfn-active_subject">
+active
+subject
+</dfn>
+-
+the
+currently
+active
+subject
+that
+the
+processor
+should
+use
+when
+generating
+triples.
+</li>
+<li>
+<dfn title="inherited_subject" id="dfn-inherited_subject">
+inherited
+subject
+</dfn>
+-
+a
+subject
+that
+was
+detected
+at
+a
+higher
+level
+of
+processing
+to
+be
+used
+to
+generate
+a
+triple
+once
+a
+<a class="tref" title="current_subject">
+current
+subject
+</a>
+is
+discovered
+or
+generated.
+</li>
+<li>
+<dfn title="active_property" id="dfn-active_property">
+active
+property
+</dfn>
+-
+the
+currently
+active
+property
+that
+the
+processor
+should
+use
+when
+generating
+triples.
+</li>
+<li>
+<dfn title="inherited_property" id="dfn-inherited_property">
+inherited
+property
+</dfn>
+-
+a
+property
+that
+was
+detected
+at
+a
+higher
+level
+of
+processing
+to
+be
+used
+to
+generate
+a
+triple
+once
+a
+<a class="tref" title="current_subject">
+current
+subject
+</a>
+is
+discovered
+or
+generated.
+</li>
+<li>
+<dfn title="active_object" id="dfn-active_object">
+active
+object
+</dfn>
+-
+the
+currently
+active
+object
+that
+the
+processor
+should
+use
+when
+generating
+triples.
+</li>
+<li>
+<dfn title="active_context" id="dfn-active_context">
+active
+context
+</dfn>
+-
+a
+context
+that
+is
+used
+to
+resolve
+CURIEs
+while
+the
+processing
+algorithm
+is
+running.
+The
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+is
+the
+top-most
+item
+on
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+stack.
+</li>
+<li>
+<dfn title="local_context" id="dfn-local_context">
+local
+context
+</dfn>
+-
+a
+context
+that
+is
+specified
+at
+the
+JSON
+associative-array
+level,
+specified
+via
+the
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">key.
+</del>
+<ins class="diff-chg">keyword.
+</ins>
+</li>
+<li>
+<dfn title="list_of_incomplete_triples" id="dfn-list_of_incomplete_triples">
+list
+of
+incomplete
+triples
+</dfn>
+-
+A
+list
+of
+triples
+that
+have
+yet
+to
+have
+their
+subject
+set.
+</li>
+<li>
+<dfn title="list_of_unprocessed_items" id="dfn-list_of_unprocessed_items">
+list
+of
+unprocessed
+items
+</dfn>
+-
+A
+list
+of
+objects
+that
+cannot
+be
+processed
+until
+a
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+is
+detected
+or
+the
+end
+of
+the
+current
+associative-array
+is
+detected.
+</li>
+<li>
+<dfn title="processor_state" id="dfn-processor_state">
+processor
+state
+</dfn>
+-
+the
+processor
+state,
+which
+includes
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+stack,
+<a class="tref" title="current_subject">
+current
+subject
+</a>,
+<a class="tref" title="current_property">
+current
+property
+</a>,
+<a class="tref internalDFN" title="list_of_incomplete_triples" href="#dfn-list_of_incomplete_triples">
+list
+of
+incomplete
+triples
+</a>,
+and
+the
+<a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">
+list
+of
+unprocessed
+items
+</a>.
+</li>
+</ul>
+<h4 id="processing-tokens-and-keywords">
+Processing
+Tokens
+and
+Keywords
+</h4>
+<ul>
+<li>
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+-
+Used
+to
+set
+the
+active
+context.
+</li>
+<li>
+<code>
+<del class="diff-old">#base
+</del>
+<ins class="diff-chg">@base
+</ins>
+</code>
+-
+Used
+to
+set
+the
+base
+IRI
+for
+all
+object
+IRIs
+affected
+by
+the
+active
+context.
+</li>
+<li>
+<code>
+<del class="diff-old">#vocab
+</del>
+<ins class="diff-chg">@vocab
+</ins>
+</code>
+-
+Used
+to
+set
+the
+base
+IRI
+for
+all
+property
+IRIs
+affected
+by
+the
+active
+context.
+</li>
+<li>
+<code>
+<del class="diff-old">#types
+</del>
+<ins class="diff-chg">@coerce
+</ins>
+</code>
+-
+Used
+to
+specify
+type
+<del class="diff-old">coercion.
+</del>
+<ins class="diff-chg">coercion
+rules.
+</ins>
+</li>
+<li>
+<code>
+<ins class="diff-new">@literal
+</ins></code><ins class="diff-new">
+-
+Used
+to
+specify
+a
+literal
+value.
+</ins></li><li>
+<del class="diff-old"><
+>
+</del>
+<code>
+<ins class="diff-chg">@iri
+</ins></code><ins class="diff-chg">
+-
+Used
+to
+specify
+an
+IRI
+value.
+</ins></li><li>
+<code>
+<ins class="diff-new">@language
+</ins>
+</code>
+-
+Used
+to
+<del class="diff-old">express
+IRIs
+in
+JSON
+values.
+</del>
+<ins class="diff-chg">specify
+the
+language
+for
+a
+literal.
+</ins></li><li><code><ins class="diff-chg">
+@datatype
+</ins></code><ins class="diff-chg">
+-
+Used
+to
+specify
+the
+datatype
+for
+a
+literal.
+</ins>
+</li>
+<li>
+<code>:
+</code>
+-
+The
+separator
+for
+CURIEs
+when
+used
+in
+JSON
+keys
+or
+JSON
+values.
+</li>
+<li>
+<code>
+@
+</code>
+-
+Sets
+the
+active
+subjects.
+</li>
+<li>
+<code>
+a
+</code>
+-
+Used
+to
+set
+the
+rdf:type
+of
+the
+active
+subjects.
+</li>
+<del class="diff-old">\
+-
+Used
+as
+an
+escape
+character
+to
+escape
+all
+the
+special
+tokens
+and
+keywords.
+^^
+-
+Used
+to
+express
+the
+data
+type
+for
+Typed
+Literals.
+</del>
+</ul>
+<p>
+The
+algorithm
+below
+is
+designed
+for
+streaming
+(SAX-based)
+implementations.
+Implementers
+will
+find
+that
+non-streaming
+(document-based)
+implementations
+will
+be
+much
+easier
+to
+implement
+as
+full
+access
+to
+the
+JSON
+object
+model
+eliminates
+some
+of
+the
+steps
+that
+are
+necessary
+for
+streaming
+implementations.
+A
+conforming
+JSON-LD
+processor
+<em class="rfc2119" title="must">
+must
+</em>
+implement
+a
+processing
+algorithm
+that
+results
+in
+the
+same
+<a class="tref internalDFN" title="default_graph" href="#dfn-default_graph">
+default
+graph
+</a>
+that
+the
+following
+algorithm
+generates:
+</p>
+<ol class="algorithm">
+<li id="processing-step-default-context">
+<del class="diff-old">If
+a
+</del>
+<ins class="diff-chg">Push
+the
+</ins><a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">
+default
+context
+</a>
+<del class="diff-old">is
+supplied
+to
+the
+processing
+algorithm,
+push
+it
+</del>
+onto
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+stack.
+</li>
+<li id="processing-step-associative">
+If
+an
+associative
+array
+is
+detected,
+create
+a
+new
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>.
+Copy
+the
+<a class="tref" title="current_context">
+current
+context
+</a>
+stack
+to
+the
+newly
+created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>.
+Push
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+onto
+the
+newly
+created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>
+'s
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+stack.
+For
+each
+key-value
+pair
+in
+the
+associative
+array,
+using
+the
+newly
+created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>
+do
+the
+following:
+<ol class="algorithm">
+<li>
+If
+a
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">key
+</del>
+<ins class="diff-chg">keyword
+</ins>
+is
+found,
+the
+processor
+merges
+each
+key-value
+pair
+in
+the
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+into
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>,
+overwriting
+any
+duplicate
+values
+in
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>.
+<ins class="diff-new">If
+the
+</ins><code><ins class="diff-new">
+@coerce
+</ins></code><ins class="diff-new">
+key
+is
+found,
+the
+processor
+merges
+each
+key-value
+pair
+in
+the
+</ins><a class="tref internalDFN" title="local_context" href="#dfn-local_context"><ins class="diff-new">
+local
+context
+</ins></a><ins class="diff-new">
+'s
+</ins><code><ins class="diff-new">
+@coerce
+</ins></code><ins class="diff-new">
+mapping
+into
+the
+</ins><a class="tref internalDFN" title="active_context" href="#dfn-active_context"><ins class="diff-new">
+active
+context
+</ins></a><ins class="diff-new">
+'s
+</ins><code><ins class="diff-new">
+@coerce
+</ins></code><ins class="diff-new">
+mapping,
+overwriting
+any
+duplicate
+values
+in
+the
+</ins><a class="tref internalDFN" title="active_context" href="#dfn-active_context"><ins class="diff-new">
+active
+context
+</ins></a><ins class="diff-new">
+'s
+</ins><code><ins class="diff-new">
+@coerce
+</ins></code><ins class="diff-new">
+mapping.
+</ins>
+Process
+each
+object
+in
+the
+<a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">
+list
+of
+unprocessed
+items
+</a>,
+starting
+at
+<a href="#processing-subject">
+Step
+2.2
+</a>.
+</li>
+<li id="processing-associative">
+If
+the
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+has
+not
+been
+detected,
+the
+current
+key-value
+pair
+is
+placed
+into
+the
+<a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">
+list
+of
+unprocessed
+items
+</a>
+and
+processing
+proceeds
+to
+the
+next
+key-value
+pair.
+Otherwise,
+if
+the
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+is
+known
+perform
+the
+following
+steps:
+</li>
+<ol class="algorithm">
+<li id="processing-subject">
+If
+a
+<code>
+@
+</code>
+key
+is
+found,
+the
+processor
+sets
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+to
+the
+value
+after
+<a href="#markup-of-rdf-concepts">
+Object
+Processing
+</a>
+has
+been
+performed.
+<ol class="algorithm">
+<li>
+If
+the
+<a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">
+inherited
+subject
+</a>
+and
+<a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">
+inherited
+property
+</a>
+values
+are
+specified,
+generate
+a
+triple
+using
+the
+<a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">
+inherited
+subject
+</a>
+for
+the
+subject,
+the
+<a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">
+inherited
+property
+</a>
+for
+the
+property,
+and
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+for
+the
+object.
+</li>
+<li>
+If
+there
+are
+any
+triples
+in
+the
+<a class="tref internalDFN" title="list_of_incomplete_triples" href="#dfn-list_of_incomplete_triples">
+list
+of
+incomplete
+triples
+</a>,
+complete
+each
+triple
+using
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+as
+the
+subject
+for
+each
+triple.
+</li>
+</ol>
+</li>
+<li>
+If
+an
+<code>
+a
+</code>
+key
+is
+found,
+set
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+to
+<code>
+http://www.w3.org/1999/02/22-rdf-syntax-ns#type
+</code>.
+</li>
+<li>
+If
+a
+key
+that
+is
+not
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>,
+<code>
+@
+</code>,
+or
+<code>
+a
+<del class="diff-old">is
+found,
+</del>
+</code>,
+set
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+by
+performing
+<a href="#markup-of-rdf-concepts">
+Property
+Processing
+</a>
+on
+the
+key.
+</li>
+<li>
+If
+the
+value
+is
+not
+an
+array,
+set
+the
+<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
+active
+object
+</a>
+by
+performing
+<a href="#markup-of-rdf-concepts">
+Object
+Processing
+</a>
+on
+the
+value.
+Generate
+a
+triple
+representing
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>,
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+and
+the
+<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
+active
+object
+</a>.
+</li>
+<li>
+If
+the
+value
+is
+an
+associative
+array,
+then
+process
+the
+value
+starting
+at
+<a href="#processing-step-associative">
+Step
+2
+</a>.
+</li>
+<li>
+If
+the
+value
+is
+a
+regular
+array,
+then
+process
+the
+value
+starting
+at
+<a href="#processing-step-array">
+Step
+3
+</a>
+ensuring
+that
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+and
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+are
+copied
+to
+a
+newly
+created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>.
+</li>
+<li>
+If
+the
+end
+of
+the
+associative
+array
+is
+detected,
+and
+a
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+was
+not
+discovered,
+then:
+<ol class="algorithm">
+<li>
+Generate
+a
+<a class="tref" title="blank_node_identifier">
+blank
+node
+identifier
+</a>
+and
+set
+it
+as
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>.
+</li>
+<li>
+Complete
+any
+previously
+incomplete
+triples
+by
+running
+all
+substeps
+of
+<a href="#processing-subject">
+Step
+2.2.1
+</a>.
+</li>
+</ol>
+</li>
+<li>
+If
+the
+end
+of
+the
+associative
+array
+is
+detected,
+and
+a
+<a class="tref internalDFN" title="local_context" href="#dfn-local_context">
+local
+context
+</a>
+was
+not
+discovered,
+then
+assume
+that
+the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">
+active
+context
+</a>
+is
+unmodified
+and
+run
+all
+substeps
+of
+<a href="#processing-associative">
+Step
+2.2
+</a>
+on
+the
+<a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">
+list
+of
+unprocessed
+items
+</a>.
+</li>
+</ol>
+</ol>
+</li>
+<li id="processing-step-array">
+If
+a
+regular
+array
+is
+detected,
+process
+each
+value
+in
+the
+array
+by
+doing
+the
+following:
+<ol class="algorithm">
+<li>
+If
+the
+value
+is
+an
+associative
+array,
+processes
+per
+<a href="#processing-step-associative">
+Step
+2
+</a>,
+ensuring
+to
+set
+the
+<a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">
+inherited
+subject
+</a>
+to
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>
+and
+the
+<a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">
+inherited
+property
+</a>
+to
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+in
+the
+newly
+created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">
+processor
+state
+</a>.
+</li>
+<li>
+If
+the
+value
+is
+not
+an
+array,
+set
+the
+<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
+active
+object
+</a>
+by
+performing
+<a href="#markup-of-rdf-concepts">
+Object
+Processing
+</a>
+on
+the
+value.
+Generate
+a
+triple
+representing
+the
+<a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">
+active
+subject
+</a>,
+the
+<a class="tref internalDFN" title="active_property" href="#dfn-active_property">
+active
+property
+</a>
+and
+the
+<a class="tref internalDFN" title="active_object" href="#dfn-active_object">
+active
+object
+</a>
+and
+place
+it
+into
+the
+<a class="tref internalDFN" title="default_graph" href="#dfn-default_graph">
+default
+graph
+</a>.
+</li>
+<li>
+If
+the
+value
+is
+a
+regular
+array,
+should
+we
+support
+RDF
+List/Sequence
+Processing?
+<div class="issue">
+If
+the
+value
+is
+a
+regular
+array,
+should
+we
+support
+RDF
+List/Sequence
+generation
+of
+triples?
+For
+example,
+would
+implementing
+this
+be
+worth
+the
+more
+complex
+processing
+rules:
+"ex:orderedItems"
+:
+[["one",
+"two",
+"three"]]
+</div>
+</li>
+</ol>
+</li>
+</ol>
+</div>
+<div id="markup-of-rdf-concepts" class="section">
+<h2>
+<span class="secno">
+5.
+</span>
+Markup
+of
+RDF
+Concepts
+</h2>
+<p>
+JSON-LD
+is
+designed
+to
+ensure
+that
+most
+Linked
+Data
+concepts
+can
+be
+marked
+up
+in
+a
+way
+that
+is
+simple
+to
+understand
+and
+author
+by
+Web
+developers.
+In
+many
+cases,
+Javascript
+objects
+can
+become
+Linked
+Data
+with
+the
+simple
+addition
+of
+a
+context.
+Since
+RDF
+is
+also
+an
+important
+sub-community
+of
+the
+Linked
+Data
+movement,
+it
+is
+important
+that
+all
+RDF
+concepts
+are
+well-represented
+in
+this
+specification.
+This
+section
+details
+how
+each
+RDF
+concept
+can
+be
+expressed
+in
+JSON-LD.
+</p>
+<del class="diff-old">The
+current
+specification
+relies
+on
+microsyntaxes
+to
+express
+things
+like
+IRIs,
+typed
+literals
+and
+CURIEs.
+There
+is
+a
+small
+amount
+of
+debate
+on
+whether
+or
+not
+to
+use
+full-blown
+JSON
+objects
+containing
+things
+like
+"value"
+and
+"datatype".
+The
+original
+authors
+of
+the
+JSON-LD
+specification
+feel
+that
+microsyntaxes
+allow
+a
+much
+simpler,
+less
+error-prone
+structure
+in
+the
+JSON-LD
+objects.
+Proponents
+of
+the
+verbose
+mechanism
+assert
+that
+there
+would
+be
+less
+chance
+of
+data
+markup
+issues
+concerning
+proper
+escaping
+and
+that
+the
+objects,
+while
+more
+verbose,
+would
+be
+easier
+to
+work
+with
+within
+JavaScript
+environments.
+Feedback
+on
+this
+issue
+would
+be
+appreciated.
+</del>
+<div id="iris" class="section">
+<h3>
+<span class="secno">
+5.1
+</span>
+IRIs
+</h3>
+<p>
+Expressing
+IRIs
+are
+fundamental
+to
+Linked
+Data
+as
+that
+is
+how
+most
+subjects
+and
+many
+objects
+are
+identified.
+IRIs
+can
+be
+expressed
+<del class="diff-old">by
+wrapping
+</del>
+<ins class="diff-chg">in
+</ins>
+a
+<del class="diff-old">text
+string
+with
+the
+<
+>
+characters.
+</del>
+<ins class="diff-chg">variety
+of
+different
+ways
+in
+JSON-LD.
+</ins>
+</p>
+<del class="diff-old">{
+...
+ "foaf:homepage": "",
+...
+}
+The
+example
+above
+would
+set
+the
+object
+to
+</del>
+<ol>
+<li>
+<ins class="diff-chg">In
+general,
+</ins>
+an
+IRI
+<del class="diff-old">with
+</del>
+<ins class="diff-chg">is
+generated
+if
+it
+is
+in
+</ins>
+the
+<del class="diff-old">value
+of
+http://manu.sporny.org
+.
+As
+a
+general
+rule,
+all
+CURIEs
+and
+IRIs
+may
+be
+wrapped
+</del>
+<ins class="diff-chg">key
+position
+in
+an
+associative
+array.
+There
+are
+special
+rules
+for
+processing
+keys
+</ins>
+in
+<code>
+<del class="diff-old"><
+>
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">characters.
+This
+is
+to
+ensure
+that
+there
+is
+a
+simple,
+consistent
+rule
+that
+can
+be
+followed
+</del>
+<ins class="diff-chg">and
+</ins>
+when
+<del class="diff-old">authoring
+JSON-LD
+data.
+There
+are,
+however,
+several
+instances
+where
+angle
+brackets
+may
+be
+omitted,
+without
+introducing
+ambiguity,
+to
+ease
+authoring
+burden.
+These
+instances
+are:
+When
+specifying
+</del>
+<ins class="diff-chg">dealing
+with
+keys
+that
+start
+with
+</ins>
+the
+<del class="diff-old">subject
+</del>
+<code>
+<ins class="diff-chg">@
+</ins></code><ins class="diff-chg">
+character.
+</ins></li><li><ins class="diff-chg">
+An
+</ins>
+IRI
+<ins class="diff-new">is
+generated
+for
+the
+value
+specified
+</ins>
+using
+<code>
+@
+<del class="diff-old">.
+</del>
+</code>,
+<ins class="diff-chg">if
+it
+is
+a
+string.
+</ins>
+</li>
+<li>
+<del class="diff-old">When
+specifying
+the
+RDF
+type
+</del>
+<ins class="diff-chg">An
+</ins>
+IRI
+<ins class="diff-new">is
+generated
+for
+the
+value
+specified
+</ins>
+using
+<code>
+a
+</code>.
+</li>
+<li>
+<del class="diff-old">Any
+CURIE
+in
+</del>
+<ins class="diff-chg">An
+IRI
+is
+generated
+for
+</ins>
+the
+<del class="diff-old">key
+portion
+of
+a
+JSON
+associative
+array.
+Wrapping
+IRIs
+with
+</del>
+<ins class="diff-chg">value
+specified
+using
+</ins>
+the
+<code>
+<del class="diff-old"><
+>
+</del>
+<ins class="diff-chg">@iri
+</ins>
+</code>
+<del class="diff-old">characters
+are
+only
+mandatory
+</del>
+<ins class="diff-chg">keyword.
+</ins></li><li><ins class="diff-chg">
+An
+IRI
+is
+generated
+</ins>
+when
+<del class="diff-old">IRIs
+</del>
+<ins class="diff-chg">there
+</ins>
+are
+<del class="diff-old">specified
+as
+values
+</del>
+<code>
+<ins class="diff-chg">@coerce
+</ins></code><ins class="diff-chg">
+rules
+</ins>
+in
+<del class="diff-old">the
+JSON
+key-value
+pairs.
+</del>
+<ins class="diff-chg">effect
+for
+</ins><code><ins class="diff-chg">
+xsd:anyURI
+</ins></code><ins class="diff-chg">
+for
+a
+particular
+vocabulary
+term.
+</ins></li></ol>
+<p>
+<ins class="diff-chg">An
+example
+of
+IRI
+generation
+for
+a
+key
+outside
+of
+a
+</ins><code><ins class="diff-chg">
+@context
+</ins></code>:
+</p>
+<pre class="example">
+<ins class="diff-new">{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}
+</ins></pre>
+<p>
+<del class="diff-old">To
+further
+illustrate,
+</del>
+<ins class="diff-chg">In
+</ins>
+the
+<del class="diff-old">following
+</del>
+example
+<del class="diff-old">omissions
+of
+</del>
+<ins class="diff-chg">above,
+</ins>
+the
+<ins class="diff-new">key
+</ins>
+<code>
+<del class="diff-old"><
+>
+</del>
+<ins class="diff-chg">http://xmlns.com/foaf/0.1/name
+</ins>
+</code>
+<del class="diff-old">characters
+are
+allowed:
+</del>
+<ins class="diff-chg">is
+interpreted
+as
+an
+IRI,
+as
+opposed
+to
+being
+interpreted
+as
+a
+string..
+</ins></p><p><ins class="diff-chg">
+CURIE
+expansion
+also
+occurs
+for
+keys
+in
+JSON-LD:
+</ins>
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "@": "",
+ // CURIE/IRI when specifying the subject can be minimized.
+ "@": "http://manu.sporny.org/about#manu",
+</del>
+<ins class="diff-chg"> "<span class="diff">foaf:name</span>": "Manu Sporny",
+</ins>
+...
+<del class="diff-old"> "a": "",
+ // CURIE/IRI when specifying the type of an object can be minimized.
+ "a": "foaf:Person",
+</del>
+<ins class="diff-chg">}
+</ins></pre><p><code><ins class="diff-chg">
+foaf:name
+</ins></code><ins class="diff-chg">
+above
+will
+automatically
+expand
+out
+to
+the
+IRI
+</ins><code><ins class="diff-chg">
+http://xmlns.com/foaf/0.1/name
+</ins></code>.</p><p><ins class="diff-chg">
+An
+IRI
+is
+generated
+when
+a
+value
+is
+associated
+with
+a
+key
+using
+the
+</ins><code><ins class="diff-chg">
+@iri
+</ins></code><ins class="diff-chg">
+keyword:
+</ins></p><pre class="example"><ins class="diff-chg">
+{
+</ins>
+...
+<del class="diff-old"> "": "<http://manu.sporny.org>",
+ // CURIE/IRI when specifying a property can be minimized.
+ "foaf:homepage": "<http://manu.sporny.org>",
+</del>
+<ins class="diff-chg"> "foaf:homepage": { "<span class="diff">@iri</span>": "http://manu.sporny.org" }
+</ins>
+...
+}
+</pre>
+<p>
+<del class="diff-old">At
+all
+other
+times,
+CURIEs
+and
+IRIs
+must
+be
+wrapped
+with
+</del>
+<ins class="diff-chg">If
+type
+coercion
+rules
+are
+specified
+in
+</ins>
+the
+<code>
+<del class="diff-old"><
+>
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+<del class="diff-old">characters.
+</del>
+<ins class="diff-chg">for
+a
+particular
+vocabulary
+term,
+an
+IRI
+is
+generated:
+</ins>
+</p>
+<pre class="example">
+<ins class="diff-new">{<span class="diff">
+ "@context":
+ {
+ "@coerce":
+ {
+ "xsd:anyURI": "foaf:homepage"
+ }
+ }</span>
+...
+ "foaf:homepage": "http://manu.sporny.org",
+...
+}
+</ins></pre>
+</div>
+<div id="identifying-the-subject" class="section">
+<h3>
+<span class="secno">
+5.2
+</span>
+Identifying
+the
+Subject
+</h3>
+<p>
+A
+subject
+is
+declared
+using
+the
+<code>
+@
+</code>
+key.
+The
+subject
+is
+the
+first
+piece
+of
+information
+needed
+by
+the
+JSON-LD
+processor
+in
+order
+to
+create
+the
+(subject,
+<del class="diff-old">predicate,
+</del>
+<ins class="diff-chg">property,
+</ins>
+object)
+tuple,
+also
+known
+as
+a
+triple.
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "",
+</del>
+<ins class="diff-chg"> "<span class="diff">@</span>": "<span class="diff">http://example.org/people#joebob</span>",
+</ins>
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+set
+the
+subject
+to
+the
+IRI
+<code>
+http://example.org/people#joebob
+</code>.
+</p>
+<del class="diff-old">Note
+that
+subject
+do
+not
+need
+to
+be
+wrapped
+in
+angle
+brackets.
+The
+following
+example
+is
+valid
+JSON-LD
+markup:
+{
+...
+ "@": "http://example.org/people#joebob",
+...
+}
+</del>
+</div>
+<div id="specifying-the-type" class="section">
+<h3>
+<span class="secno">
+5.3
+</span>
+Specifying
+the
+Type
+</h3>
+<p>
+The
+type
+of
+a
+particular
+subject
+can
+be
+specified
+using
+the
+<code>
+a
+</code>
+key.
+Specifying
+the
+type
+in
+this
+way
+will
+generate
+a
+triple
+of
+the
+form
+(subject,
+type,
+type-url).
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "@": "<http://example.org/people#joebob>",
+ "",
+</del>
+<ins class="diff-chg"> "@": "http://example.org/people#joebob",
+ "<span class="diff">a</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+</ins>
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+triple
+(in
+N-Triples
+notation):
+</p>
+<pre class="example">
+<http://example.org/people#joebob>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+<http://xmlns.com/foaf/0.1/Person>
+.
+</pre>
+<del class="diff-old">Note
+that
+the
+type
+IRI
+does
+not
+need
+to
+be
+wrapped
+in
+angle
+brackets.
+The
+following
+example
+is
+valid
+JSON-LD
+markup:
+{
+...
+ "@": "http://example.org/people#joebob",
+ "a": "http://xmlns.com/foaf/0.1/Person",
+...
+}
+</del>
+</div>
+<div id="plain-literals" class="section">
+<h3>
+<span class="secno">
+5.4
+</span>
+Plain
+Literals
+</h3>
+<p>
+Regular
+text
+strings
+are
+called
+"plain
+literals"
+in
+RDF
+and
+are
+easily
+expressed
+using
+regular
+JSON
+strings.
+</p>
+<pre class="example">
+{
+...
+ "foaf:name": "<span class="diff">Mark Birbeck</span>",
+...
+}
+</pre>
+</div>
+<div id="language-specification-in-plain-literals" class="section">
+<h3>
+<span class="secno">
+5.5
+</span>
+Language
+Specification
+in
+Plain
+Literals
+</h3>
+<p>
+JSON-LD
+<del class="diff-old">attempts
+to
+make
+sure
+that
+it
+is
+easy
+to
+express
+triples
+in
+other
+languages
+while
+simultaneously
+ensuring
+</del>
+<ins class="diff-chg">makes
+an
+assumption
+</ins>
+that
+<del class="diff-old">hefty
+data
+structures
+aren't
+required
+to
+accomplish
+simple
+</del>
+<ins class="diff-chg">plain
+literals
+with
+associated
+</ins>
+language
+<del class="diff-old">markup.
+When
+the
+@
+symbol
+</del>
+<ins class="diff-chg">encoding
+information
+</ins>
+is
+<ins class="diff-new">not
+very
+common
+when
+</ins>
+used
+in
+<ins class="diff-new">JavaScript
+and
+Web
+Services.
+Thus,
+it
+takes
+</ins>
+a
+<del class="diff-old">literal,
+the
+JSON-LD
+processor
+tags
+the
+literal
+text
+with
+the
+language
+tag
+that
+follows
+the
+@
+symbol.
+</del>
+<ins class="diff-chg">little
+more
+effort
+to
+express
+plain
+literals
+in
+a
+specified
+language.
+</ins>
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "foaf:name": "",
+</del>
+<ins class="diff-chg"> "foaf:name": <span class="diff">
+ {
+ "@literal": "花澄",
+ "@language": "ja"
+ }</span>
+</ins>
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+a
+plain
+literal
+for
+<em>
+<del class="diff-old">??
+</del>
+<ins class="diff-chg">花澄
+</ins>
+</em>
+and
+associate
+the
+<code>
+ja
+</code>
+language
+tag
+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-literals" class="section">
+<h3>
+<span class="secno">
+5.6
+</span>
+Typed
+Literals
+</h3>
+<p>
+Literals
+may
+also
+be
+typed
+in
+JSON-LD
+<del class="diff-old">by
+using
+</del>
+<ins class="diff-chg">in
+two
+ways:
+</ins></p><ol><li><ins class="diff-chg">
+By
+utilizing
+</ins>
+the
+<code>
+<del class="diff-old">^^
+</del>
+<ins class="diff-chg">@coerce
+</ins>
+</code>
+<del class="diff-old">sequence
+at
+</del>
+<ins class="diff-chg">keyword.
+</ins></li><li><ins class="diff-chg">
+By
+utilizing
+</ins>
+the
+<del class="diff-old">end
+of
+</del>
+<ins class="diff-chg">expanded
+form
+for
+specifying
+objects.
+</ins></li></ol><p><ins class="diff-chg">
+The
+first
+example
+uses
+</ins>
+the
+<del class="diff-old">text
+string.
+</del>
+<code>
+<ins class="diff-chg">@coerce
+</ins></code><ins class="diff-chg">
+keyword
+to
+express
+a
+typed
+literal:
+</ins>
+</p>
+<pre class="example">
+<del class="diff-old">{
+</del>
+<ins class="diff-chg">{<span class="diff">
+ "@context":
+ {
+ "@coerce":
+ {
+ "xsd:dateTime": "dc:modified"
+ }
+ }</span>
+</ins>
+...
+<del class="diff-old"> "dc:modified": "",
+</del>
+<ins class="diff-chg"> "dc:modified": "2010-05-29T14:17:39+02:00",
+</ins>
+...
+}
+</pre>
+<p>
+The
+<ins class="diff-new">second
+</ins>
+example
+<ins class="diff-new">uses
+the
+expanded
+form
+for
+specifying
+objects:
+</ins></p><pre class="example"><ins class="diff-new">
+{
+...
+ "dc:modified": <span class="diff">
+ {
+ "@literal": "2010-05-29T14:17:39+02:00",
+ "@datatype": "xsd:dateTime"
+ }</span>
+...
+}
+</ins></pre><p><ins class="diff-new">
+Both
+examples
+</ins>
+above
+would
+generate
+an
+object
+with
+the
+<ins class="diff-new">literal
+</ins>
+value
+of
+<code>
+2010-05-29T14:17:39+02:00
+</code>
+and
+the
+datatype
+of
+<code>
+http://www.w3.org/2001/XMLSchema#dateTime
+</code>.
+</p>
+</div>
+<div id="multiple-objects-for-a-single-property" class="section">
+<h3>
+<span class="secno">
+5.7
+</span>
+Multiple
+Objects
+for
+a
+Single
+Property
+</h3>
+<p>
+A
+JSON-LD
+author
+can
+express
+multiple
+triples
+in
+a
+compact
+way
+by
+using
+arrays.
+If
+a
+subject
+has
+multiple
+values
+for
+the
+same
+property,
+the
+author
+<em class="rfc2119" title="may">
+may
+</em>
+express
+each
+property
+as
+an
+array.
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "@": "<http://example.org/people#joebob>",
+ "foaf:nick": ,
+</del>
+<ins class="diff-chg"> "@": "http://example.org/people#joebob",
+ "foaf:nick": <span class="diff">["joe", "bob", "jaybee"]</span>,
+</ins>
+...
+}
+</pre>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+<del class="diff-old"> "stu" .
+</del>
+<ins class="diff-chg"> "joe" .
+</ins>
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+<del class="diff-old"> "groknar" .
+</del>
+<ins class="diff-chg"> "bob" .
+</ins>
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+<del class="diff-old">"radface"
+</del>
+<ins class="diff-chg">"jaybee"
+</ins>
+.
+</pre>
+</div>
+<div id="multiple-typed-literals-for-a-single-property" class="section">
+<h3>
+<span class="secno">
+5.8
+</span>
+Multiple
+Typed
+Literals
+for
+a
+Single
+Property
+</h3>
+<p>
+Multiple
+typed
+literals
+<del class="diff-old">are
+</del>
+<ins class="diff-chg">may
+also
+be
+</ins>
+expressed
+<del class="diff-old">very
+much
+in
+</del>
+<ins class="diff-chg">using
+</ins>
+the
+<del class="diff-old">same
+way
+as
+multiple
+properties:
+</del>
+<ins class="diff-chg">expanded
+form
+for
+objects:
+</ins>
+</p>
+<pre class="example">
+{
+...
+<del class="diff-old"> "@": "<http://example.org/articles/8>",
+ "dcterms:modified": ],
+</del>
+<ins class="diff-chg"> "@": "http://example.org/articles/8",
+ "dcterms:modified": <span class="diff">
+ [
+ {
+ "@literal": "2010-05-29T14:17:39+02:00",
+ "@datatype": "xsd:dateTime"
+ },
+ {
+ "@literal": "2010-05-30T09:21:28-04:00",
+ "@datatype": "xsd:dateTime"
+ }
+ ]</span>
+</ins>
+...
+}
+</pre>
+<p>
+The
+markup
+shown
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">
+<http://example.org/articles/8>
+ <http://purl.org/dc/terms/modified>
+ "2010-05-29T14:17:39+02:00"^^http://www.w3.org/2001/XMLSchema#dateTime .
+<http://example.org/articles/8>
+ <http://purl.org/dc/terms/modified>
+"2010-05-30T09:21:28-04:00"^^http://www.w3.org/2001/XMLSchema#dateTime
+.
+</pre>
+</div>
+<div id="blank-nodes" class="section">
+<h3>
+<span class="secno">
+5.9
+</span>
+Blank
+Nodes
+</h3>
+<p>
+At
+times,
+it
+becomes
+necessary
+to
+be
+able
+to
+express
+information
+without
+being
+able
+to
+specify
+the
+subject.
+Typically,
+this
+is
+where
+blank
+nodes
+come
+into
+play.
+In
+JSON-LD,
+blank
+node
+identifiers
+are
+automatically
+created
+if
+a
+subject
+is
+not
+specified
+using
+the
+<code>
+@
+</code>
+<del class="diff-old">key.
+</del>
+<ins class="diff-chg">keyword.
+</ins>
+However,
+authors
+may
+name
+blank
+nodes
+by
+using
+the
+special
+<code>
+_
+</code>
+CURIE
+prefix.
+</p>
+<pre class="example">
+{
+...
+ "@": "<span class="diff">_:foo</span>",
+...
+}
+</pre>
+<p>
+The
+example
+above
+would
+set
+the
+subject
+to
+<code>
+_:foo
+</code>,
+which
+can
+then
+be
+used
+later
+on
+in
+the
+JSON-LD
+markup
+to
+refer
+back
+to
+the
+named
+blank
+node.
+</p>
+</div>
+</div>
+<div id="advanced-features" class="section">
+<h2>
+<span class="secno">
+6.
+</span>
+Advanced
+Features
+</h2>
+<p>
+JSON-LD
+has
+a
+number
+of
+features
+that
+provide
+functionality
+above
+and
+beyond
+the
+core
+functionality
+provided
+by
+RDF.
+The
+following
+sections
+outline
+the
+features
+that
+are
+specific
+to
+JSON-LD.
+</p>
+<del class="diff-old">6.1
+Escape
+Character
+Special
+characters
+in
+property
+values
+must
+be
+escaped
+in
+order
+to
+not
+be
+interpreted
+as
+CURIEs,
+IRIs,
+language
+tags,
+or
+TypedLiterals.
+The
+special
+characters
+that
+need
+to
+be
+escaped
+in
+property
+values
+are:
+<
+>
+(at
+the
+end
+of
+a
+string),
+@
+,
+and
+^
+.
+{
+...
+ "example:code": ,
+...
+}
+</del>
+<div id="automatic-typing" class="section">
+<h3>
+<span class="secno">
+<del class="diff-old">6.2
+</del>
+<ins class="diff-chg">6.1
+</ins>
+</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 href="#typed-literals">
+Typed
+Literals
+</a>:
+</p>
+<pre class="example">
+{
+...
+ // The following two values are automatically converted to a type of xsd:double
+ // and both values are equivalent to each other.
+ "measure:cups": <span class="diff">5.3</span>,
+ "measure:cups": <span class="diff">5.3e0</span>,
+ // The following value is automatically converted to a type of xsd:double as well
+ "space:astronomicUnits": <span class="diff">6.5e73</span>,
+ // The following value should never be converted to a language-native type
+<del class="diff-old"> "measure:stones": ,
+</del>
+<ins class="diff-chg"> "measure:stones": <span class="diff">{ "@literal": "4.8", "@datatype": "xsd:decimal" }</span>,
+</ins>
+ // This value is automatically converted to having a type of xsd:integer
+ "chem:protons": <span class="diff">12</span>,
+ // This value is automatically converted to having a type of xsd:boolean
+ "sensor:active": <span class="diff">true</span>,
+...
+}
+</pre>
+<p class="note">
+When
+dealing
+with
+a
+number
+of
+modern
+programming
+languages,
+including
+JavaScript
+ECMA-262,
+there
+is
+no
+distinction
+between
+<strong>
+xsd:decimal
+</strong>
+and
+<strong>
+xsd:double
+</strong>
+values.
+That
+is,
+the
+number
+<code>
+5.3
+</code>
+and
+the
+number
+<code>
+5.3e0
+</code>
+are
+treated
+as
+if
+they
+were
+the
+same.
+When
+converting
+from
+JSON-LD
+to
+a
+language-native
+format
+and
+back,
+datatype
+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
+datatype
+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
+datatype
+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">
+<del class="diff-old">6.3
+</del>
+<ins class="diff-chg">6.2
+</ins>
+</span>
+Type
+Coercion
+</h3>
+<p>
+JSON-LD
+supports
+the
+coercion
+of
+types
+to
+ensure
+that
+the
+zero-edit
+goal
+of
+JSON-LD
+can
+be
+accomplished.
+Type
+coercion
+allows
+someone
+deploying
+JSON-LD
+to
+coerce
+and
+incoming
+or
+outgoing
+types
+to
+the
+proper
+RDF
+type
+based
+on
+a
+mapping
+of
+type
+IRIs
+to
+RDF
+types.
+Using
+type
+conversion,
+one
+may
+convert
+simple
+JSON
+data
+to
+properly
+typed
+RDF
+data.
+</p>
+<p>
+The
+example
+below
+demonstrates
+how
+a
+JSON-LD
+author
+can
+coerce
+values
+to
+plain
+literals,
+typed
+literals
+and
+IRIs.
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "#":
+</del>
+<ins class="diff-chg"> "@context":
+</ins>
+ {
+ "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age": "http://xmlns.com/foaf/0.1/age",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage",
+<del class="diff-old"> "#types":
+</del>
+<span class="diff"> "@type":
+ {
+<del class="diff-old"> "name": "rdf:PlainLiteral",
+ "age": "xsd:integer",
+ "homepage": "xsd:anyURI",
+</del>
+<ins class="diff-chg"> "xsd:integer": "age",
+ "xsd:anyURI": "homepage",
+</ins>
+ }</span>
+ },
+<del class="diff-old"> "name": ,
+</del>
+<ins class="diff-chg"> "name": "John Smith",
+</ins>
+ "age": <span class="diff">"41"</span>,
+ "homepage": <span class="diff">"http://example.org/home/"</span>
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">
+_:bnode1
+ <http://xmlns.com/foaf/0.1/name>
+<del class="diff-old"> "<John Smith>" .
+</del>
+<ins class="diff-chg"> "John Smith" .
+</ins>
+_:bnode1
+ <http://xmlns.com/foaf/0.1/age>
+ "41"^^http://www.w3.org/2001/XMLSchema#integer .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/homepage>
+<http://example.org/home/>
+.
+</pre>
+</div>
+</div>
+<div id="best-practices" class="section">
+<h2>
+<span class="secno">
+7.
+</span>
+Best
+Practices
+</h2>
+<p>
+The
+nature
+of
+Web
+programming
+allows
+one
+to
+use
+basic
+technologies,
+such
+as
+JSON-LD,
+across
+a
+variety
+of
+systems
+and
+environments.
+This
+section
+attempts
+to
+describe
+some
+of
+those
+environments
+and
+the
+way
+in
+which
+JSON-LD
+can
+be
+integrated
+in
+order
+to
+help
+alleviate
+certain
+development
+headaches.
+</p>
+<div id="javascript" class="section">
+<h3>
+<span class="secno">
+7.1
+</span>
+JavaScript
+</h3>
+<p class="issue">
+It
+is
+expected
+that
+JSON-LD
+will
+be
+used
+quite
+a
+bit
+in
+JavaScript
+environments,
+however,
+features
+like
+<del class="diff-old">IRIs
+requiring
+angled
+brackets
+in
+JSON-LD
+means
+</del>
+<ins class="diff-chg">the
+expanded
+form
+for
+object
+values
+mean
+</ins>
+that
+using
+JSON-LD
+directly
+in
+JavaScript
+<del class="diff-old">is
+going
+to
+</del>
+<ins class="diff-chg">may
+</ins>
+be
+annoying
+without
+a
+middleware
+layer
+such
+as
+a
+simple
+library
+that
+<del class="diff-old">strips
+</del>
+<ins class="diff-chg">converts
+</ins>
+JSON-LD
+markup
+before
+JavaScript
+uses
+it.
+One
+could
+say
+that
+JSON-LD
+is
+a
+good
+fit
+for
+the
+<del class="diff-old">RDFa
+</del>
+<ins class="diff-chg">RDF
+</ins>
+API,
+which
+<del class="diff-old">would
+enable
+</del>
+<ins class="diff-chg">enables
+</ins>
+a
+<del class="diff-old">triple-store
+in
+the
+browser,
+</del>
+<ins class="diff-chg">variety
+of
+RDF-based
+Web
+Applications,
+</ins>
+but
+some
+don't
+want
+to
+require
+that
+level
+of
+functionality
+just
+to
+use
+JSON-LD.
+The
+group
+is
+still
+discussing
+the
+best
+way
+to
+proceed,
+so
+input
+on
+how
+JSON-LD
+could
+more
+easily
+be
+utilized
+in
+JavaScript
+environments
+would
+be
+very
+much
+appreciated.
+</p>
+</div>
+<div id="schema-less-databases" class="section">
+<h3>
+<span class="secno">
+7.2
+</span>
+Schema-less
+Databases
+</h3>
+<p class="issue">
+Databases
+such
+as
+CouchDB
+and
+MongoDB
+allow
+the
+creation
+of
+schema-less
+data
+stores.
+RDF
+is
+a
+type
+of
+schema-less
+data
+model
+and
+thus
+lends
+itself
+to
+databases
+such
+as
+CouchDB
+and
+MongoDB.
+Both
+of
+these
+databases
+can
+use
+JSON-LD
+as
+their
+storage
+format.
+The
+group
+needs
+feedback
+from
+CouchDB
+and
+MongoDB
+experts
+regarding
+the
+usefulness
+of
+JSON-LD
+in
+those
+environments.
+</p>
+</div>
+</div>
+<div id="advanced-concepts" class="section">
+<h2>
+<span class="secno">
+8.
+</span>
+Advanced
+Concepts
+</h2>
+<p class="issue">
+There
+are
+a
+few
+advanced
+concepts
+where
+it
+is
+not
+clear
+whether
+or
+not
+the
+JSON-LD
+specification
+is
+going
+to
+support
+the
+complexity
+necessary
+to
+support
+each
+concept.
+The
+entire
+section
+on
+Advanced
+Concepts
+should
+be
+<del class="diff-old">taken
+with
+a
+grain
+of
+salt;
+</del>
+<ins class="diff-chg">considered
+as
+discussion
+points;
+</ins>
+it
+is
+merely
+a
+list
+of
+possibilities
+where
+all
+of
+the
+benefits
+and
+drawbacks
+have
+not
+been
+explored.
+</p>
+<div id="vocabulary-profiles" class="section">
+<h3>
+<span class="secno">
+8.1
+</span>
+Vocabulary
+Profiles
+</h3>
+<p>
+One
+of
+the
+more
+powerful
+features
+of
+RDFa
+1.1
+Core
+is
+the
+ability
+to
+specify
+a
+collection
+of
+prefixes
+and
+terms
+that
+can
+be
+re-used
+by
+a
+processor
+to
+simplfy
+markup.
+JSON-LD
+provides
+a
+similar
+mechanism
+called
+Vocabulary
+Profiles,
+which
+is
+the
+inclusion
+of
+a
+context
+external
+to
+the
+JSON-LD
+document.
+</p>
+<p>
+The
+example
+below
+demonstrates
+how
+one
+may
+specify
+an
+external
+Vocabulary
+Profile.
+Assume
+the
+following
+profile
+exists
+at
+this
+imaginary
+URL:
+<code>
+http://example.org/profiles/contacts
+</code>.
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "#":
+</del>
+<ins class="diff-chg"> "@context":
+</ins>
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age": "http://xmlns.com/foaf/0.1/age",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage",
+ "#types":
+ {
+ "age": "xsd:integer",
+ "homepage": "xsd:anyURI",
+ }
+ }
+}
+</pre>
+<p>
+The
+profile
+listed
+above
+can
+be
+used
+in
+the
+following
+way:
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "#": { "#profile": "http://example.org/profiles/contacts" },
+</del>
+<ins class="diff-chg"> "@profile": "http://example.org/profiles/contacts",
+</ins>
+ "name": "John Smith",
+ "age": "41",
+ "homepage": "http://example.org/home/"
+}
+</pre>
+<p>
+The
+example
+above
+would
+generate
+the
+following
+triples:
+</p>
+<pre class="example">
+_:bnode1
+ <http://xmlns.com/foaf/0.1/name>
+ "John Smith" .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/age>
+ "41"^^http://www.w3.org/2001/XMLSchema#integer .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/homepage>
+<http://example.org/home/>
+.
+</pre>
+</div>
+<div id="disjoint-graphs" class="section">
+<h3>
+<span class="secno">
+8.2
+</span>
+Disjoint
+Graphs
+</h3>
+<p>
+When
+serializing
+an
+RDF
+graph
+that
+contains
+two
+or
+more
+sections
+of
+the
+graph
+which
+are
+entirely
+disjoint,
+one
+must
+use
+an
+array
+to
+express
+the
+graph
+as
+two
+graphs.
+This
+may
+not
+be
+acceptable
+to
+some
+authors,
+who
+would
+rather
+express
+the
+information
+as
+one
+graph.
+Since,
+by
+definition,
+disjoint
+graphs
+require
+there
+to
+be
+two
+top-level
+objects,
+JSON-LD
+utilizes
+a
+mechanism
+that
+allows
+disjoint
+graphs
+to
+be
+expressed
+using
+a
+single
+graph.
+</p>
+<p>
+Assume
+the
+following
+RDF
+graph:
+</p>
+<pre class="example">
+<http://example.org/people#john>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+ <http://xmlns.com/foaf/0.1/Person> .
+<http://example.org/people#jane>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+<http://xmlns.com/foaf/0.1/Person>
+.
+</pre>
+<p>
+Since
+the
+two
+subjects
+are
+entirely
+disjoint
+with
+one
+another,
+it
+is
+impossible
+to
+express
+the
+RDF
+graph
+above
+using
+a
+single
+JSON-LD
+associative
+array.
+</p>
+<p>
+In
+JSON-LD,
+one
+can
+use
+the
+subject
+to
+express
+disjoint
+graphs
+as
+a
+single
+graph:
+</p>
+<pre class="example">
+{
+<del class="diff-old"> "#": { "foaf": "http://xmlns.com/foaf/0.1/" },
+</del>
+ "@":
+ [
+ {
+<del class="diff-old"> "@": "<http://example.org/people#john>",
+</del>
+<ins class="diff-chg"> "@": "http://example.org/people#john",
+</ins>
+ "a": "foaf:Person"
+ },
+ {
+<del class="diff-old"> "@": "<http://example.org/people#jane>",
+</del>
+<ins class="diff-chg"> "@": "http://example.org/people#jane",
+</ins>
+ "a": "foaf:Person"
+ }
+ ]
+}
+</pre>
+<p>
+<ins class="diff-new">A
+disjoint
+graph
+could
+also
+be
+expressed
+like
+so:
+</ins></p><pre class="example"><ins class="diff-new">
+[
+ {
+ "@": "http://example.org/people#john",
+ "a": "foaf:Person"
+ },
+ {
+ "@": "http://example.org/people#jane",
+ "a": "foaf:Person"
+ }
+]
+</ins></pre>
+</div>
+<div id="the-json-ld-api" class="section">
+<h3>
+<span class="secno">
+8.3
+</span>
+The
+JSON-LD
+API
+</h3>
+<p>
+This
+API
+provides
+a
+clean
+mechanism
+that
+enables
+developers
+to
+convert
+JSON-LD
+data
+into
+a
+format
+that
+is
+easier
+to
+work
+with
+in
+various
+programming
+languages.
+</p>
+<pre class="idl">
+<del class="diff-old">]
+interface {
+</del>
+<span class="idlInterface" id="idl-def-JSONLDProcessor">[<span class="extAttr">NoInterfaceObject</span>]
+<ins class="diff-chg">interface <span class="idlInterfaceID">JSONLDProcessor</span> {
+</ins><span class="idlMethod"> <span class="idlMethType"><a>object</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessor-toProjection-object-DOMString-jsonld-object-template-DOMString-subject-JSONLDParserCallback-callback">toProjection</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">jsonld</span></span>, <span class="idlParam">in <span class="idlParamType"><a>object</a>?</span> <span class="idlParamName">template</span></span>, <span class="idlParam">in <span class="idlParamType"><a>DOMString</a>?</span> <span class="idlParamName">subject</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a>JSONLDParserCallback</a>?</span> <span class="idlParamName">callback</span></span>);</span><span class="idlMethod"> <span class="idlMethType"><a>Graph</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessor-toGraph-Graph-DOMString-jsonld-JSONLDParserCallback-callback">toGraph</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">jsonld</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a>JSONLDParserCallback</a>?</span> <span class="idlParamName">callback</span></span>);</span>
+};</span>
+</pre>
+<div id="methods" class="section">
+<h4>
+<span class="secno">
+8.3.1
+</span>
+Methods
+</h4>
+<dl class="methods">
+<dt id="widl-JSONLDProcessor-toGraph-Graph-DOMString-jsonld-JSONLDParserCallback-callback">
+<code>
+<del class="diff-old">toObject
+</del>
+<ins class="diff-chg">toGraph
+</ins>
+</code>
+</dt>
+<dd>
+Parses
+JSON-LD
+<del class="diff-old">text
+</del>
+<ins class="diff-chg">and
+transforms
+the
+data
+</ins>
+into
+an
+<del class="diff-old">object
+that
+allows
+at
+least
+attribute-based
+or
+key-based
+access
+to
+the
+data.
+If
+</del>
+<ins class="diff-chg">Graph,
+which
+is
+compatible
+with
+</ins>
+the
+<del class="diff-old">contents
+are
+a
+disjoint
+graph,
+an
+array
+of
+objects
+are
+returned.
+If
+</del>
+<ins class="diff-chg">RDF
+Interfaces
+API
+specification
+[
+</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-INTERFACES"><ins class="diff-chg">
+RDF-INTERFACES
+</ins></a></cite><ins class="diff-chg">
+].
+This
+method
+will
+return
+</ins><code><ins class="diff-chg">
+null
+</ins></code><ins class="diff-chg">
+if
+</ins>
+there
+are
+any
+errors,
+<del class="diff-old">null
+</del>
+<ins class="diff-chg">or
+if
+the
+RDF
+Interfaces
+API
+</ins>
+is
+<del class="diff-old">returned.
+</del>
+<ins class="diff-chg">not
+available
+for
+use.
+</ins>
+<table class="parameters">
+<tr>
+<th>
+Parameter
+</th>
+<th>
+Type
+</th>
+<th>
+Nullable
+</th>
+<th>
+Optional
+</th>
+<th>
+Description
+</th>
+</tr>
+<tr>
+<td class="prmName">
+jsonld
+</td>
+<td class="prmType">
+<code>
+<a>
+DOMString
+</a>
+</code>
+</td>
+<td class="prmNullFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmOptFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmDesc">
+The
+JSON-LD
+string
+to
+parse
+into
+the
+<del class="diff-old">return
+object.
+map
+object
+?
+?
+The
+map
+from
+IRIs
+to
+attribute
+names
+for
+the
+resulting
+object.
+Any
+term
+mapping
+that
+is
+not
+mentioned
+in
+the
+map
+will
+not
+be
+available
+in
+the
+resulting
+object.
+You
+may
+map
+rdf:type
+using
+the
+a
+key
+or
+the
+rdf:type
+IRI.
+You
+may
+map
+the
+subject
+by
+using
+the
+@
+key.
+options
+object
+?
+?
+An
+associative-array
+of
+processing
+options
+to
+enable
+or
+disable
+when
+processing
+the
+JSON-LD
+string.
+A
+conforming
+JSON-LD
+processor
+must
+support
+the
+following
+options:
+indexBySubject
+If
+set
+to
+true,
+the
+returned
+object
+will
+be
+indexed
+by
+subject.
+preserveDatatypes
+If
+set
+to
+true,
+preserves
+the
+datatype
+for
+object
+literals.
+preserveLanguage
+If
+set
+to
+true,
+preserves
+the
+languages
+for
+object
+literals.
+</del>
+<ins class="diff-chg">RDFGraph.
+</ins>
+</td>
+</tr>
+<tr>
+<td class="prmName">
+callback
+</td>
+<td class="prmType">
+<code>
+<a>
+JSONLDParserCallback
+</a>
+</code>
+</td>
+<td class="prmNullTrue">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✔
+</ins>
+</td>
+<td class="prmOptTrue">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✔
+</ins>
+</td>
+<td class="prmDesc">
+A
+callback
+that
+is
+called
+whenever
+a
+processing
+error
+occurs
+on
+the
+given
+JSON-LD
+string.
+</td>
+</tr>
+</table>
+<div>
+<em>
+No
+exceptions.
+</em>
+</div>
+<div>
+<em>
+Return
+type:
+</em>
+<code>
+<a>
+<del class="diff-old">object
+</del>
+<ins class="diff-chg">Graph
+</ins>
+</a>
+</code>
+</div>
+</dd>
+<dt id="widl-JSONLDProcessor-toProjection-object-DOMString-jsonld-object-template-DOMString-subject-JSONLDParserCallback-callback">
+<code>
+<del class="diff-old">toRDFGraph
+</del>
+<ins class="diff-chg">toProjection
+</ins>
+</code>
+</dt>
+<dd>
+Parses
+JSON-LD
+<del class="diff-old">and
+transforms
+the
+data
+</del>
+<ins class="diff-chg">text
+</ins>
+into
+an
+<del class="diff-old">RDFGraph,
+which
+is
+compatible
+with
+</del>
+<ins class="diff-chg">RDF
+API
+Projection
+object
+as
+specified
+by
+</ins>
+the
+<del class="diff-old">RDFa
+</del>
+<ins class="diff-chg">RDF
+</ins>
+API
+<del class="diff-old">specification.
+This
+method
+will
+return
+null
+if
+</del>
+<ins class="diff-chg">specification
+[
+</ins><cite><a class="bibref" rel="biblioentry" href="#bib-RDF-API"><ins class="diff-chg">
+RDF-API
+</ins></a></cite><ins class="diff-chg">
+].
+If
+</ins>
+there
+are
+any
+errors,
+<del class="diff-old">or
+if
+the
+RDFa
+API
+</del>
+<code>
+<ins class="diff-chg">null
+</ins></code>
+is
+<del class="diff-old">not
+available
+for
+use.
+</del>
+<ins class="diff-chg">returned.
+</ins>
+<table class="parameters">
+<tr>
+<th>
+Parameter
+</th>
+<th>
+Type
+</th>
+<th>
+Nullable
+</th>
+<th>
+Optional
+</th>
+<th>
+Description
+</th>
+</tr>
+<tr>
+<td class="prmName">
+jsonld
+</td>
+<td class="prmType">
+<code>
+<a>
+DOMString
+</a>
+</code>
+</td>
+<td class="prmNullFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmOptFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmDesc">
+The
+JSON-LD
+string
+to
+parse
+into
+the
+<del class="diff-old">RDFGraph.
+</del>
+<ins class="diff-chg">Projection.
+</ins>
+</td>
+</tr>
+<tr>
+<td class="prmName">
+<del class="diff-old">callback
+</del>
+<ins class="diff-chg">template
+</ins>
+</td>
+<td class="prmType">
+<code>
+<a>
+<ins class="diff-chg">object
+</ins></a></code></td><td class="prmNullTrue"><ins class="diff-chg">
+✔
+</ins></td><td class="prmOptFalse"><ins class="diff-chg">
+✘
+</ins></td><td class="prmDesc"><ins class="diff-chg">
+The
+Projection
+template
+to
+use
+when
+building
+the
+Projection.
+</ins></td></tr><tr><td class="prmName"><ins class="diff-chg">
+subject
+</ins></td><td class="prmType">
+<code>
+<del class="diff-old">JSONLDParserCallback
+</del>
+<a>
+<ins class="diff-chg">DOMString
+</ins></a>
+</code>
+</td>
+<td class="prmNullTrue">
+<ins class="diff-new">✔
+</ins></td><td class="prmOptFalse"><ins class="diff-new">
+✘
+</ins></td><td class="prmDesc"><ins class="diff-new">
+The
+subject
+to
+use
+when
+building
+the
+Projection.
+</ins></td></tr><tr><td class="prmName"><ins class="diff-new">
+callback
+</ins></td><td class="prmType"><code><a><ins class="diff-new">
+JSONLDParserCallback
+</ins>
+</a>
+</code>
+</td>
+<td class="prmNullTrue">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✔
+</ins>
+</td>
+<td class="prmOptTrue">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✔
+</ins>
+</td>
+<td class="prmDesc">
+A
+callback
+that
+is
+called
+whenever
+a
+processing
+error
+occurs
+on
+the
+given
+JSON-LD
+string.
+</td>
+</tr>
+</table>
+<div>
+<em>
+No
+exceptions.
+</em>
+</div>
+<div>
+<em>
+Return
+type:
+</em>
+<code>
+<a>
+<del class="diff-old">RDFGraph
+</del>
+<ins class="diff-chg">object
+</ins>
+</a>
+</code>
+</div>
+</dd>
+</dl>
+</div>
+<p>
+The
+JSONLDParserCallback
+is
+called
+whenever
+a
+processing
+error
+occurs
+on
+input
+data.
+</p>
+<pre class="idl">
+<del class="diff-old">]
+interface {
+</del>
+<span class="idlInterface" id="idl-def-JSONLDProcessorCallback">[<span class="extAttr">NoInterfaceObject Callback</span>]
+<ins class="diff-chg">interface <span class="idlInterfaceID">JSONLDProcessorCallback</span> {
+</ins><span class="idlMethod"> <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessorCallback-error-void-DOMString-error">error</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">error</span></span>);</span>
+};</span>
+</pre>
+<div id="methods-1" class="section">
+<h4>
+<span class="secno">
+8.3.2
+</span>
+Methods
+</h4>
+<dl class="methods">
+<dt id="widl-JSONLDProcessorCallback-error-void-DOMString-error">
+<code>
+error
+</code>
+</dt>
+<dd>
+This
+callback
+is
+invoked
+whenever
+an
+error
+occurs
+during
+processing.
+<table class="parameters">
+<tr>
+<th>
+Parameter
+</th>
+<th>
+Type
+</th>
+<th>
+Nullable
+</th>
+<th>
+Optional
+</th>
+<th>
+Description
+</th>
+</tr>
+<tr>
+<td class="prmName">
+error
+</td>
+<td class="prmType">
+<code>
+<a>
+DOMString
+</a>
+</code>
+</td>
+<td class="prmNullFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmOptFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmDesc">
+A
+descriptive
+error
+string
+returned
+by
+the
+processor.
+</td>
+</tr>
+</table>
+<div>
+<em>
+No
+exceptions.
+</em>
+</div>
+<div>
+<em>
+Return
+type:
+</em>
+<code>
+<a>
+void
+</a>
+</code>
+</div>
+</dd>
+</dl>
+</div>
+<p>
+The
+following
+example
+demonstrates
+how
+to
+convert
+JSON-LD
+to
+a
+<del class="diff-old">JSON
+object
+</del>
+<ins class="diff-chg">projection
+</ins>
+that
+is
+directly
+usable
+in
+a
+programming
+environment:
+</p>
+<pre class="example">
+// retrieve JSON-LD from a Web Service
+var jsonldString = fetchPerson();
+// This map, usually defined once per script, defines how to map incoming
+// JSON-LD to JavaScript objects
+<del class="diff-old">var myMap = { "http://xmlns.com/foaf/0.1/name" : "name",
+ "http://xmlns.com/foaf/0.1/age" : "age",
+ "http://xmlns.com/foaf/0.1/homepage" : "homepage" };
+</del>
+<ins class="diff-chg">var myTemplate = { "http://xmlns.com/foaf/0.1/name" : "name",
+ "http://xmlns.com/foaf/0.1/age" : "age",
+ "http://xmlns.com/foaf/0.1/homepage" : "homepage" };
+</ins>
+// Map the JSON-LD to a language-native object
+<del class="diff-old">var person = jsonld.toObject(jsonldString, myMap);
+</del>
+<ins class="diff-chg">var person = jsonld.toProjection(jsonldString, myTemplate);
+</ins>
+// Use the language-native object
+alert(person.name + " is " + person.age + " years old. " +
+"Their
+homepage
+is:
+"
++
+person.homepage);
+</pre>
+<p>
+A
+JSON-LD
+Serializer
+is
+also
+available
+to
+map
+a
+language-native
+object
+to
+JSON-LD.
+</p><pre class="idl">
+<span class="idlInterface" id="idl-def-JSONLDSerializer">[<span class="extAttr">NoInterfaceObject</span>]
+interface <span class="idlInterfaceID">JSONLDSerializer</span> {
+<span class="idlMethod"> <span class="idlMethType"><a>DOMString</a></span> <span class="idlMethName"><a href="#widl-JSONLDSerializer-normalize-DOMString-object-obj">normalize</a></span> (<span class="idlParam">in <span class="idlParamType"><a>object</a></span> <span class="idlParamName">obj</span></span>);</span>
+};</span>
+</pre>
+<div id="methods-2" class="section">
+<h4>
+<span class="secno">
+8.3.3
+</span>
+Methods
+</h4>
+<dl class="methods">
+<dt id="widl-JSONLDSerializer-normalize-DOMString-object-obj">
+<code>
+normalize
+</code>
+</dt>
+<dd>
+Serializes
+a
+language-native
+object
+into
+a
+normalized
+JSON-LD
+string.
+Normalization
+is
+important
+when
+performing
+things
+like
+equality
+comparison
+and
+digital
+signature
+creation
+and
+verification.
+<table class="parameters">
+<tr>
+<th>
+Parameter
+</th>
+<th>
+Type
+</th>
+<th>
+Nullable
+</th>
+<th>
+Optional
+</th>
+<th>
+Description
+</th>
+</tr>
+<tr>
+<td class="prmName">
+obj
+</td>
+<td class="prmType">
+<code>
+<a>
+object
+</a>
+</code>
+</td>
+<td class="prmNullFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmOptFalse">
+<del class="diff-old">?
+</del>
+<ins class="diff-chg">✘
+</ins>
+</td>
+<td class="prmDesc">
+An
+associative
+array
+of
+key-value
+pairs
+that
+should
+be
+converted
+to
+a
+JSON-LD
+string.
+It
+is
+assumed
+that
+a
+map
+already
+exists
+for
+the
+data.
+</td>
+</tr>
+</table>
+<div>
+<em>
+No
+exceptions.
+</em>
+</div>
+<div>
+<em>
+Return
+type:
+</em>
+<code>
+<a>
+DOMString
+</a>
+</code>
+</div>
+</dd>
+</dl>
+</div>
+<h3 id="the-normalization-algorithm">
+The
+Normalization
+Algorithm
+</h3>
+<p class="issue">
+This
+algorithm
+is
+very
+rough,
+untested,
+and
+probably
+contains
+many
+bugs.
+Use
+at
+your
+own
+risk.
+It
+will
+change
+in
+the
+coming
+months.
+</p>
+<p>
+The
+JSON-LD
+normalization
+algorithm
+is
+as
+follows:
+</p>
+<ol class="algorithm">
+<li>
+Remove
+the
+<code>
+<del class="diff-old">#
+</del>
+<ins class="diff-chg">@context
+</ins>
+</code>
+key
+and
+preserve
+it
+as
+the
+<dfn title="transformation_map" id="dfn-transformation_map">
+transformation
+map
+</dfn>
+while
+running
+this
+algorithm.
+</li>
+<li>
+For
+each
+key
+<ol class="algorithm">
+<li>
+If
+the
+key
+is
+a
+CURIE,
+expand
+the
+CURIE
+to
+an
+IRI
+using
+the
+<a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">
+transformation
+map
+</a>.
+</li>
+<del class="diff-old">If
+the
+transformed
+key
+is
+an
+IRI,
+ensure
+that
+it
+is
+surrounded
+by
+angle
+brackets.
+</del>
+</ol>
+</li>
+<li>
+For
+each
+value
+<ol class="algorithm">
+<li>
+If
+the
+value
+should
+be
+type
+coerced
+per
+the
+<a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">
+transformation
+map
+</a>,
+ensure
+that
+it
+is
+transformed
+to
+the
+new
+value.
+</li>
+<li>
+If
+the
+value
+is
+a
+CURIE,
+expand
+the
+CURIE
+to
+an
+IRI
+using
+the
+<a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">
+transformation
+map
+</a>.
+</li>
+<li>
+If
+the
+value
+is
+a
+Typed
+Literal
+and
+the
+type
+is
+a
+CURIE,
+expand
+it
+to
+an
+IRI
+using
+the
+<a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">
+transformation
+map
+</a>.
+</li>
+<li>
+<del class="diff-old">If
+</del>
+<ins class="diff-chg">When
+generating
+</ins>
+the
+final
+<ins class="diff-new">value,
+use
+expanded
+object
+</ins>
+value
+<del class="diff-old">is
+an
+IRI,
+ensure
+that
+it
+is
+surrounded
+by
+angle
+brackets.
+</del>
+<ins class="diff-chg">form
+to
+store
+all
+IRIs,
+typed
+literals
+and
+plain
+literals
+with
+language
+information.
+</ins>
+</li>
+</ol>
+</li>
+<li>
+Output
+each
+sorted
+key-value
+pair
+without
+any
+extraneous
+whitespace.
+If
+the
+value
+is
+an
+associative
+array,
+perform
+this
+algorithm,
+starting
+at
+step
+#1,
+recursively
+on
+the
+sub-tree.
+<ins class="diff-new">There
+should
+be
+no
+nesting
+in
+the
+outputted
+JSON
+data.
+That
+is,
+the
+top-most
+element
+should
+be
+an
+array.
+Each
+item
+in
+the
+array
+contains
+a
+single
+subject
+with
+a
+corresponding
+array
+of
+properties
+in
+UTF-8
+sort
+order.
+Any
+related
+objects
+that
+are
+complex
+objects
+themselves
+should
+be
+given
+a
+top-level
+object
+in
+the
+top-level
+array.
+</ins>
+</li>
+</ol>
+<p class="issue">
+<ins class="diff-chg">Note
+that
+normalizing
+named
+blank
+nodes
+is
+impossible
+at
+present
+since
+one
+would
+have
+to
+specify
+a
+blank
+node
+naming
+algorithm.
+For
+the
+time
+being,
+you
+cannot
+normalize
+graphs
+that
+contain
+named
+blank
+nodes.
+However,
+normalizing
+graphs
+that
+contain
+non-named
+blank
+nodes
+is
+supported.
+</ins>
+</p>
+<pre class="example">
+<del class="diff-old">var myObj = { "#" : {
+</del>
+<ins class="diff-chg">var myObj = { "@context" : {
+</ins>
+ "xsd" : "http://www.w3.org/2001/XMLSchema#",
+ "name" : "http://xmlns.com/foaf/0.1/name",
+ "age" : "http://xmlns.com/foaf/0.1/age",
+ "homepage" : "http://xmlns.com/foaf/0.1/homepage",
+<del class="diff-old"> "#types": {
+ "age" : "xsd:nonNegativeInteger",
+ "homepage" : "xsd:anyURI"
+</del>
+<ins class="diff-chg"> "@type": {
+ "xsd:nonNegativeInteger": "age",
+ "xsd:anyURI": "homepage"
+</ins>
+ }
+ },
+ "name" : "Joe Jackson",
+ "age" : 42,
+ "homepage" : "http://example.org/people/joe" };
+// Map the language-native object to JSON-LD
+var
+jsonldText
+=
+jsonld.normalize(myObj);
+</pre>
+<p>
+After
+the
+code
+in
+the
+example
+above
+has
+executed,
+the
+<strong>
+jsonldText
+</strong>
+value
+will
+be
+(line-breaks
+added
+for
+readability):
+</p>
+<pre class="example">
+<del class="diff-old">{"<http://xmlns.com/foaf/0.1/age>":"42^^<http://www.w3.org/2001/XMLSchema#nonNegativeInteger>",
+"<http://xmlns.com/foaf/0.1/homepage>":"<http://example.org/people/joe>",
+"<http://xmlns.com/foaf/0.1/name>":"Joe
+Jackson"}
+</del>
+<ins class="diff-chg">[{"http://xmlns.com/foaf/0.1/age":{"@datatype":"http://www.w3.org/2001/XMLSchema#nonNegativeInteger","@literal":"42"},
+"http://xmlns.com/foaf/0.1/homepage":{"@iri":"http://example.org/people/joe"},
+"http://xmlns.com/foaf/0.1/name":"Joe
+Jackson"}]
+</ins>
+</pre>
+<p>
+When
+normalizing
+<strong>
+xsd:double
+</strong>
+values,
+implementers
+<em class="rfc2119" title="must">
+must
+</em>
+ensure
+that
+the
+normalized
+value
+is
+a
+string.
+In
+order
+to
+generate
+the
+string
+from
+a
+<strong>
+double
+</strong>
+value,
+output
+equivalent
+to
+the
+<code>
+printf("%1.6e",
+value)
+</code>
+function
+in
+C
+<em class="rfc2119" title="must">
+must
+</em>
+be
+used
+where
+<strong>
+"%1.6e"
+</strong>
+is
+the
+string
+formatter
+and
+<strong>
+value
+</strong>
+is
+the
+value
+to
+be
+converted.
+</p>
+<p>
+To
+convert
+the
+a
+double
+value
+in
+JavaScript,
+implementers
+can
+use
+the
+following
+snippet
+of
+code:
+</p>
+<pre class="example">
+// the variable 'value' below is the JavaScript native double value that is to be converted
+(value).toExponential(6).replace(/(e(?:\+|-))([0-9])$/,
+'$10$2')
+</pre>
+<p class="note">
+When
+data
+needs
+to
+be
+normalized,
+JSON-LD
+authors
+should
+not
+use
+values
+that
+are
+going
+to
+undergo
+automatic
+conversion.
+This
+is
+due
+to
+the
+lossy
+nature
+of
+<strong>
+xsd:double
+</strong>
+values.
+</p>
+</div>
+</div>
+<div class="appendix section" id="the-default-context">
+<h2>
+<span class="secno">
+A.
+</span>
+<ins class="diff-new">The
+Default
+Context
+</ins></h2><p><ins class="diff-new">
+The
+</ins><dfn title="default_context" id="dfn-default_context-1"><ins class="diff-new">
+default
+context
+</ins></dfn><ins class="diff-new">
+is
+provided
+to
+ensure
+that
+there
+are
+a
+reasonable
+set
+of
+prefixes
+and
+terms
+available
+to
+all
+JSON-LD
+developers.
+Mappings
+specified
+by
+the
+default
+context
+</ins><em class="rfc2119" title="should not"><ins class="diff-new">
+should
+not
+</ins></em><ins class="diff-new">
+be
+overwritten
+by
+JSON-LD
+authors.
+All
+JSON-LD
+processors
+</ins><em class="rfc2119" title="must"><ins class="diff-new">
+must
+</ins></em><ins class="diff-new">
+load
+the
+following
+context
+in
+as
+the
+intial
+context
+before
+processing
+JSON-LD
+text.
+</ins></p><pre><ins class="diff-new">
+{
+ "@context":
+ {
+ "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
+ "owl": "http://www.w3.org/2002/07/owl#",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "dcterms": "http://purl.org/dc/terms/",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "cal": "http://www.w3.org/2002/12/cal/ical#",
+ "vcard": "http://www.w3.org/2006/vcard/ns# ",
+ "geo": "http://www.w3.org/2003/01/geo/wgs84_pos#",
+ "cc": "http://creativecommons.org/ns#",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "doap": "http://usefulinc.com/ns/doap#",
+ "com": "http://purl.org/commerce#",
+ "ps": "http://purl.org/payswarm#",
+ "gr": "http://purl.org/goodrelations/v1#",
+ "sig": "http://purl.org/signature#",
+ "ccard": "http://purl.org/commerce/creditcard#"
+ "@coerce":
+ {
+ "xsd:anyURI": ["foaf:homepage", "foaf:member"],
+ "xsd:integer": "foaf:age"
+ }
+ }
+}
+</ins></pre></div><div class="appendix section" id="acknowledgements"><h2><span class="secno"><ins class="diff-new">
+B.
+</ins></span>
+Acknowledgements
+</h2>
+<p>
+The
+editor
+would
+like
+to
+thank
+Mark
+Birbeck,
+who
+provided
+a
+great
+deal
+of
+the
+rationale
+and
+reasoning
+behind
+the
+JSON-LD
+work
+via
+his
+work
+on
+RDFj,
+Dave
+Longley
+who
+<del class="diff-old">reviewed
+and
+</del>
+<ins class="diff-chg">reviewed,
+</ins>
+provided
+<del class="diff-old">feedback
+</del>
+<ins class="diff-chg">feedback,
+and
+performed
+several
+implementation
+</ins>
+on
+the
+<del class="diff-old">overall
+specification
+and
+contexts,
+</del>
+<ins class="diff-chg">specification,
+</ins>
+and
+Ian
+Davis,
+who
+created
+RDF/JSON.
+Thanks
+also
+to
+<ins class="diff-new">Nathan
+Rixham,
+</ins>
+Bradley
+P.
+Allen
+and
+Richard
+Cyganiak
+for
+their
+input
+on
+the
+specification.
+</p>
+</div>
+<div id="references" class="appendix section">
+<h2>
+<span class="secno">
+<del class="diff-old">B.
+</del>
+<ins class="diff-chg">C.
+</ins>
+</span>
+References
+</h2>
+<div id="normative-references" class="section">
+<h3>
+<span class="secno">
+<del class="diff-old">B.1
+</del>
+<ins class="diff-chg">C.1
+</ins>
+</span>
+Normative
+references
+</h3>
+<dl class="bibliography">
+<dt id="bib-BCP47">
+[BCP47]
+</dt>
+<dd>
+A.
+Phillips,
+M.
+Davis.
+<a href="http://tools.ietf.org/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-RDF-API">
+<ins class="diff-new">[RDF-API]
+</ins></dt><dd><ins class="diff-new">
+Manu
+Sporny,
+Benjamin
+Adrian,
+Nathan
+Rixham;
+et
+al.
+</ins><a href="http://www.w3.org/2010/02/rdfa/sources/rdf-api/"><cite><ins class="diff-new">
+RDF
+API
+</ins></cite></a><ins class="diff-new">
+Latest.
+W3C
+Editor's
+Draft.
+URL:
+</ins><a href="http://www.w3.org/2010/02/rdfa/sources/rdf-api/"><ins class="diff-new">
+http://www.w3.org/2010/02/rdfa/sources/rdf-api/
+</ins></a></dd>
+<dt id="bib-RDF-CONCEPTS">
+[RDF-CONCEPTS]
+</dt>
+<dd>
+Graham
+Klyne;
+Jeremy
+J.
+Carroll.
+<a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210">
+<cite>
+Resource
+Description
+Framework
+(RDF):
+Concepts
+and
+Abstract
+Syntax.
+</cite>
+</a>
+10
+February
+2004.
+W3C
+Recommendation.
+URL:
+<a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210">
+http://www.w3.org/TR/2004/REC-rdf-concepts-20040210
+</a>
+</dd>
+<dt id="bib-RDF-INTERFACES">
+<ins class="diff-new">[RDF-INTERFACES]
+</ins></dt><dd><ins class="diff-new">
+Nathan
+Rixham,
+Manu
+Sporny,
+Benjamin
+Adrian;
+et
+al.
+</ins><a href="http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/"><cite><ins class="diff-new">
+RDF
+Interfaces
+</ins></cite></a><ins class="diff-new">
+Latest.
+W3C
+Editor's
+Draft.
+URL:
+</ins><a href="http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/"><ins class="diff-new">
+http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/
+</ins></a></dd>
+<dt id="bib-RFC4627">
+[RFC4627]
+</dt>
+<dd>
+D.
+<del class="diff-old">Crockford
+</del>
+<ins class="diff-chg">Crockford.
+</ins>
+<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>
+</dl>
+</div>
+<div id="informative-references" class="section">
+<h3>
+<span class="secno">
+<del class="diff-old">B.2
+</del>
+<ins class="diff-chg">C.2
+</ins>
+</span>
+Informative
+references
+</h3>
+<dl class="bibliography">
+<dt id="bib-MICRODATA">
+[MICRODATA]
+</dt>
+<dd>
+Ian
+Hickson;
+et
+al.
+<a href="http://www.w3.org/TR/microdata/">
+<cite>
+Microdata
+</cite>
+</a>
+04
+March
+2010.
+W3C
+Working
+Draft.
+URL:
+<a href="http://www.w3.org/TR/microdata/">
+http://www.w3.org/TR/microdata/
+</a>
+</dd>
+<dt id="bib-MICROFORMATS">
+[MICROFORMATS]
+</dt>
+<dd>
+<a href="http://microformats.org">
+<cite>
+Microformats
+</cite>
+</a>.
+URL:
+<a href="http://microformats.org">
+http://microformats.org
+</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-20110331">
+<cite>
+RDFa
+Core
+1.1:
+Syntax
+and
+processing
+rules
+for
+embedding
+RDF
+through
+attributes.
+</cite>
+</a>
+<del class="diff-old">26
+October
+2010.
+</del>
+<ins class="diff-chg">31
+March
+2011.
+</ins>
+W3C
+Working
+Draft.
+URL:
+<del class="diff-old">http://www.w3.org/TR/2010/WD-rdfa-core-20101026
+</del>
+<a href="http://www.w3.org/TR/2011/WD-rdfa-core-20110331">
+<ins class="diff-chg">http://www.w3.org/TR/2011/WD-rdfa-core-20110331
+</ins>
+</a>
+</dd>
+</dl>
+</div>
+</div>
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+
+<body style="display: inherit; "><div class="head"><p></p><h1 class="title" id="title">JSON-LD - Linked Data Expression in JSON</h1><h2 id="subtitle">A Context-based JSON Serialization for Linked Data</h2><h2 id="unofficial-draft-07-may-2011">Unofficial Draft 07 May 2011</h2><dl><dt>Editor:</dt><dd><a href="http://digitalbazaar.com/">Manu Sporny</a>, <a href="http://digitalbazaar.com/">Digital Bazaar, Inc.</a></dd>
+<dt>Authors:</dt><dd><a href="http://webbackplane.com/">Mark Birbeck</a>, <a href="http://webbackplane.com/">Backplane Ltd.</a></dd>
+<dd><a href="http://digitalbazaar.com/">Manu Sporny</a>, <a href="http://digitalbazaar.com/">Digital Bazaar, Inc.</a></dd>
+</dl><p>This document is also available in this non-normative format: <a href="diff-20110201.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>
+Developers that embed structured data in their Web pages can choose among
+a number of languages such as RDFa [<cite><a class="bibref" rel="biblioentry" href="#bib-RDFA-CORE">RDFA-CORE</a></cite>], Microformats [<cite><a class="bibref" rel="biblioentry" href="#bib-MICROFORMATS">MICROFORMATS</a></cite>]
+and Microdata [<cite><a class="bibref" rel="biblioentry" href="#bib-MICRODATA">MICRODATA</a></cite>]. Each of these structured data languages, while
+incompatible at the syntax level, can be easily mapped to RDF. JSON has
+proven to be a highly useful object serialization and messaging format.
+In an attempt to harmonize the representation of Linked Data in JSON,
+this specification outlines a common JSON representation format for
+Linked Data that can be used to represent objects specified via RDFa,
+Microformats and Microdata.
+</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="#contributing" class="tocxref"><span class="secno">1.2 </span>Contributing</a></li></ul></li><li class="tocline"><a href="#design-goals-and-rationale" class="tocxref"><span class="secno">2. </span>Design Goals and Rationale</a><ul class="toc"><li class="tocline"><a href="#goals" class="tocxref"><span class="secno">2.1 </span>Goals</a></li><li class="tocline"><a href="#map-terms-to-iris" class="tocxref"><span class="secno">2.2 </span>Map Terms to IRIs</a></li><li class="tocline"><a href="#the-json-ld-context" class="tocxref"><span class="secno">2.3 </span>The JSON-LD Context</a></li><li class="tocline"><a href="#unambiguous-identifiers-for-json" class="tocxref"><span class="secno">2.4 </span>Unambiguous Identifiers for JSON</a></li><li class="tocline"><a href="#mashing-up-vocabularies" class="tocxref"><span class="secno">2.5 </span>Mashing Up Vocabularies</a></li><li class="tocline"><a href="#an-example-of-a-context" class="tocxref"><span class="secno">2.6 </span>An Example of a Context</a></li></ul></li><li class="tocline"><a href="#markup-examples" class="tocxref"><span class="secno">3. </span>Markup Examples</a><ul class="toc"><li class="tocline"><a href="#rdfa" class="tocxref"><span class="secno">3.1 </span>RDFa</a></li><li class="tocline"><a href="#microformats" class="tocxref"><span class="secno">3.2 </span>Microformats</a></li><li class="tocline"><a href="#microdata" class="tocxref"><span class="secno">3.3 </span>Microdata</a></li></ul></li><li class="tocline"><a href="#the-json-ld-processing-algorithm" class="tocxref"><span class="secno">4. </span>The JSON-LD Processing Algorithm</a></li><li class="tocline"><a href="#markup-of-rdf-concepts" class="tocxref"><span class="secno">5. </span>Markup of RDF Concepts</a><ul class="toc"><li class="tocline"><a href="#iris" class="tocxref"><span class="secno">5.1 </span>IRIs</a></li><li class="tocline"><a href="#identifying-the-subject" class="tocxref"><span class="secno">5.2 </span>Identifying the Subject</a></li><li class="tocline"><a href="#specifying-the-type" class="tocxref"><span class="secno">5.3 </span>Specifying the Type</a></li><li class="tocline"><a href="#plain-literals" class="tocxref"><span class="secno">5.4 </span>Plain Literals</a></li><li class="tocline"><a href="#language-specification-in-plain-literals" class="tocxref"><span class="secno">5.5 </span>Language Specification in Plain Literals</a></li><li class="tocline"><a href="#typed-literals" class="tocxref"><span class="secno">5.6 </span>Typed Literals</a></li><li class="tocline"><a href="#multiple-objects-for-a-single-property" class="tocxref"><span class="secno">5.7 </span>Multiple Objects for a Single Property</a></li><li class="tocline"><a href="#multiple-typed-literals-for-a-single-property" class="tocxref"><span class="secno">5.8 </span>Multiple Typed Literals for a Single Property</a></li><li class="tocline"><a href="#blank-nodes" class="tocxref"><span class="secno">5.9 </span>Blank Nodes</a></li></ul></li><li class="tocline"><a href="#advanced-features" class="tocxref"><span class="secno">6. </span>Advanced Features</a><ul class="toc"><li class="tocline"><a href="#automatic-typing" class="tocxref"><span class="secno">6.1 </span>Automatic Typing</a></li><li class="tocline"><a href="#type-coercion" class="tocxref"><span class="secno">6.2 </span>Type Coercion</a></li></ul></li><li class="tocline"><a href="#best-practices" class="tocxref"><span class="secno">7. </span>Best Practices</a><ul class="toc"><li class="tocline"><a href="#javascript" class="tocxref"><span class="secno">7.1 </span>JavaScript</a></li><li class="tocline"><a href="#schema-less-databases" class="tocxref"><span class="secno">7.2 </span>Schema-less Databases</a></li></ul></li><li class="tocline"><a href="#advanced-concepts" class="tocxref"><span class="secno">8. </span>Advanced Concepts</a><ul class="toc"><li class="tocline"><a href="#vocabulary-profiles" class="tocxref"><span class="secno">8.1 </span>Vocabulary Profiles</a></li><li class="tocline"><a href="#disjoint-graphs" class="tocxref"><span class="secno">8.2 </span>Disjoint Graphs</a></li><li class="tocline"><a href="#the-json-ld-api" class="tocxref"><span class="secno">8.3 </span>The JSON-LD API</a><ul class="toc"><li class="tocline"><a href="#methods" class="tocxref"><span class="secno">8.3.1 </span>Methods</a></li><li class="tocline"><a href="#methods-1" class="tocxref"><span class="secno">8.3.2 </span>Methods</a></li><li class="tocline"><a href="#methods-2" class="tocxref"><span class="secno">8.3.3 </span>Methods</a></li></ul></li></ul></li><li class="tocline"><a href="#the-default-context" class="tocxref"><span class="secno">A. </span>The Default Context</a></li><li class="tocline"><a href="#acknowledgements" class="tocxref"><span class="secno">B. </span>Acknowledgements</a></li><li class="tocline"><a href="#references" class="tocxref"><span class="secno">C. </span>References</a><ul class="toc"><li class="tocline"><a href="#normative-references" class="tocxref"><span class="secno">C.1 </span>Normative references</a></li><li class="tocline"><a href="#informative-references" class="tocxref"><span class="secno">C.2 </span>Informative references</a></li></ul></li></ul></div>
+
+
+
+<div id="introduction" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">1. </span>Introduction</h2>
+
+JSON-LD is designed as a light-weight syntax that can be used to express
+Linked Data. It is primarily intended to be a way to express 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 existing code that is in use today. It is designed to be able to
+express key-value pairs, RDF data, Microformats data, and Microdata.
+That is, it supports every major Web-based structured data model in use
+today. It does not require anyone to change their JSON, but easily add
+meaning by adding context in a way that is out-of-band. The syntax is
+designed to not disturb already deployed systems running on JSON, but
+provide a smooth migration path from JSON to JSON with added
+semantics. Finally, the format is intended to be fast to parse, fast to
+generate, stream-based and document-based processing compatible, and require
+a very small memory footprint in order to operate.
+<p></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 JSON for Linked
+data. The document is primarily intended for the following audiences:
+</p>
+
+<ul>
+ <li>Web developers that want to understand the design decisions and
+ language syntax for JSON-LD.</li>
+ <li>Software developers that want to encode Microformats, RDFa, or Microdata
+ in a way that is cross-language compatible via JSON.</li>
+ <li>Software developers that want to write processors for JSON-LD.</li>
+</ul>
+
+<p>
+To understand 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>] and [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-CONCEPTS">RDF-CONCEPTS</a></cite>].</p>
+</div>
+
+<div id="contributing" class="section">
+<h3><span class="secno">1.2 </span>Contributing</h3>
+
+<p>There are a number of ways that one may participate in the development of
+this specification:</p>
+
+<ul>
+<li>All comments and discussion takes place on the public mailing list:
+<a href="http://lists.w3.org/Archives/Public/public-linked-json/">public-linked-json@w3.org</a>
+</li>
+
+<li>Specification bugs and issues should be reported in the
+<a href="http://github.com/digitalbazaar/json-ld/issues">issue tracker</a>.</li>
+
+<li><a href="http://github.com/digitalbazaar/json-ld">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 id="design-goals-and-rationale" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">2. </span>Design Goals and Rationale</h2>
+
+<p>The following section outlines the design goals and rationale behind the
+JSON-LD markup language.
+</p>
+
+<div id="goals" class="section">
+<h3><span class="secno">2.1 </span>Goals</h3>
+
+<p>
+A number of design considerations were explored during the creation of this
+markup language:
+</p>
+
+<dl>
+ <dt>Simplicity</dt>
+ <dd>Developers don't need to know RDF in order to use the basic functionality
+ provided by JSON-LD.</dd>
+ <dt>Compatibility</dt>
+ <dd>The JSON-LD markup should be 100% compatible with JSON.</dd>
+ <dt>Expressiveness</dt>
+ <dd>All major RDF concepts must be expressible via the JSON-LD syntax.</dd>
+ <dt>Terseness</dt>
+ <dd>The JSON-LD syntax must be very terse and human readable.</dd>
+ <dt>Zero Edits, most of the time</dt>
+ <dd>JSON-LD provides a mechanism that allows developers to specify
+ context 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 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
+ RDF 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 we strive for Zero Edits,
+ it was not always possible without adding great complexity to the language.
+ </dd>
+ <dt>Streaming</dt>
+ <dd>The format supports both document-based and stream-based processing.</dd>
+</dl>
+</div>
+
+<div id="map-terms-to-iris" class="section">
+<h3><span class="secno">2.2 </span>Map Terms to IRIs</h3>
+
+<p>Establishing a mechanism to map JSON values to IRIs will
+help in the mapping of JSON objects to RDF. This does not mean that JSON-LD must
+be restrictive in declaring a set of terms, rather, experimentation and
+innovation should be supported as part of the core design of JSON-LD. There are,
+however, a number of very small design criteria that can ensure that developers
+will generate good RDF data that will create value for the greater
+semantic web community and JSON/REST-based Web Services community.
+</p>
+
+<p>We will be using the following JSON object as the example for this section:
+</p>
+
+<pre class="example">
+{
+ "a": "Person",
+ "name": "Manu Sporny",
+ "homepage": "http://manu.sporny.org/"
+ "avatar": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+</div>
+
+<div id="the-json-ld-context" class="section">
+<h3><span class="secno">2.3 </span>The JSON-LD Context</h3>
+
+<p>A context is used in RDFa to allow developers to use aliases for
+IRIs. The semantic web, just like the document-based web, uses IRIs for
+unambiguous identification. The idea is that these terms mean something,
+which you will eventually want to query. The semantic web specifies this via
+<em>Vocabulary Documents</em>. The IRI <em>http://xmlns.com/foaf/0.1/</em>
+specifies a Vocabulary Document, and <strong>name</strong> is a term in
+that vocabulary. Join the two items together and you have an unambiguous
+identifier for a vocabulary term. The Compact URI Expression, 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 identifies
+the given name for something, for example - a person's name.
+</p>
+
+<p>Developers, and machines, would be able to use this IRI (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 WordNet today to
+see the
+<a href="http://wordnetweb.princeton.edu/perl/webwn?s=definition">definition</a>
+of words in the English language. Machines need the same sort of
+dictionary of terms, and URIs provide a way to ensure that these terms
+are unambiguous.
+</p>
+
+<p>The context provides a collection of vocabulary terms that can be used
+for a JSON object.</p>
+</div>
+
+<div id="unambiguous-identifiers-for-json" class="section">
+<h3><span class="secno">2.4 </span>Unambiguous Identifiers for JSON</h3>
+
+<p>If a set of terms, like <strong>Person</strong>,
+<strong>name</strong>, and <strong>homepage</strong>,
+are defined in a context, and that context is used to resolve the
+names in JSON objects, machines could automatically expand the terms to
+something meaningful and unambiguous, like this:</p>
+
+<pre class="example">
+{
+ "<span class="diff">http://www.w3.org/1999/02/22-rdf-syntax-ns#type</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+ "<span class="diff">http://xmlns.com/foaf/0.1/homepage</span>": "http://manu.sporny.org"
+ "<span class="diff">http://rdfs.org/sioc/ns#avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<p>Doing this would mean that JSON would start to become unambiguously
+machine-readable, play well with the semantic web, and basic markup wouldn't
+be that much more complex than basic JSON markup. A win, all around.</p>
+</div>
+
+<div id="mashing-up-vocabularies" class="section">
+<h3><span class="secno">2.5 </span>Mashing Up Vocabularies</h3>
+
+<p>Developers would also benefit by allowing other vocabularies to be used
+automatically with their JSON API. There are over 200
+Vocabulary Documents that are available for use on the Web today. Some
+of these vocabularies are:
+</p>
+
+<ul>
+ <li>RDF - for describing information about objects on the semantic 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>Since these vocabularies are very popular, they are pre-defined in
+something called the <a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">default context</a>, which is a set of
+vocabulary prefixes that are pre-loaded in all JSON-LD processors. The
+contents of the <a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">default context</a> are provided later in this
+document. Using the <a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">default context</a> allows developers to
+express data unambiguously, like so:</p>
+
+<pre class="example">
+{
+ "<span class="diff">rdf:type</span>": "<span class="diff">foaf:Person</span>",
+ "<span class="diff">foaf:name</span>": "Manu Sporny",
+ "<span class="diff">foaf:homepage</span>": "http://manu.sporny.org/",
+ "<span class="diff">sioc:avatar</span>": "http://twitter.com/account/profile_image/manusporny"
+}</pre>
+
+<p>Developers can also specify their own Vocabulary documents by modifying the
+default context in-line using the <code>@context</code> keyword, like so:</p>
+
+<pre class="example">
+{
+ <span class="diff">"@context": { "myvocab": "http://example.org/myvocab#" }</span>,
+ "a": "foaf:Person",
+ "foaf:name": "Manu Sporny",
+ "foaf:homepage": "http://manu.sporny.org/",
+ "sioc:avatar": "http://twitter.com/account/profile_image/manusporny"<span class="diff">,
+ "myvocab:personality": "friendly"</span>
+}</pre>
+
+<p>The <code>@context</code> keyword is used to change how the JSON-LD
+processor evaluates key-value pairs. In this case, it was used to
+map one string ('myvocab') to another string, which is interpreted as
+a IRI. In the example above, the <code>myvocab</code> string is replaced
+with "<code>http://example.org/myvocab#</code>" when it
+is detected. In the example above, "<code>myvocab:personality</code>" would
+expand to "<code>http://example.org/myvocab#personality</code>".</p>
+
+<p>This mechanism is a short-hand for RDF, called a CURIE, and provides
+developers an unambiguous way to map any JSON value to RDF.</p><p>
+
+</p></div>
+
+<div id="an-example-of-a-context" class="section">
+<h3><span class="secno">2.6 </span>An Example of a Context</h3>
+
+<p>JSON-LD strives to ensure that developers don't have to change the JSON
+that is going into and being returned from their Web applications. A JSON-LD
+aware Web Service <em class="rfc2119" title="may">may</em> define a known context. For example, the
+following default context could apply to all incoming Web Service calls
+previously accepting only JSON data:</p>
+
+<pre class="example">
+{
+ "@context":
+ {
+ "@vocab": "http://example.org/default-vocab#",
+ "@base": "http://example.org/baseurl/",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "dc": "http://purl.org/dc/terms/",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "cc": "http://creativecommons.org/ns#",
+ "geo": "http://www.w3.org/2003/01/geo/wgs84_pos#",
+ "vcard": "http://www.w3.org/2006/vcard/ns#",
+ "cal": "http://www.w3.org/2002/12/cal/ical#",
+ "doap": "http://usefulinc.com/ns/doap#",
+ "Person": "http://xmlns.com/foaf/0.1/Person",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage"
+ "@coerce":
+ {
+ "xsd:anyURI": ["foaf:homepage", "foaf:member"],
+ "xsd:integer": "foaf:age"
+ }
+ }
+}</pre>
+
+<p>The <code>@vocab</code> string is a special keyword that states
+that any term that doesn't resolve to a term or a prefix should be
+appended to the <code>@vocab</code> IRI. This is done to ensure that
+terms can be transformed to an IRI at all times.
+</p>
+
+<p>The <code>@base</code> string is a special keyword that states
+that any relative IRI <em class="rfc2119" title="must">must</em> be appended to the string specified by
+<code>@base</code>.
+</p>
+
+<p>The <code>@coerce</code> keyword is used to specify type coersion
+rules for the data. For each key in the map, the key is the type to
+be coerced to and the value is the vocabulary term to be coerced.
+Type coersion for the key <code>xsd:anyURI</code> asserts that all
+vocabulary terms listed should undergo coercion to an IRI, including
+<code>@base</code> processing for relative IRIs and CURIE processing
+for compact URI Expressions like <code>foaf:homepage</code>.
+</p>
+
+</div>
+</div>
+
+<div id="markup-examples" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">3. </span>Markup Examples</h2>
+
+<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 RDFa, Microformats,
+and Microdata. These sections are merely provided as proof that JSON-LD is
+very flexible in what it can express across different Linked Data approaches.
+</p>
+
+<div id="rdfa" class="section">
+<h3><span class="secno">3.1 </span>RDFa</h3>
+
+<p>The following example describes three people with their respective names and
+homepages.</p>
+
+<pre class="example">
+<div <span class="diff">prefix="foaf: http://xmlns.com/foaf/0.1/"</span>>
+ <ul>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/bob/" property="foaf:name" </span>>Bob</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/eve/" property="foaf:name" </span>>Eve</a>
+ </li>
+ <li <span class="diff">typeof="foaf:Person"</span>>
+ <a <span class="diff">rel="foaf:homepage" href="http://example.com/manu/" property="foaf:name" </span>>Manu</a>
+ </li>
+ </ul>
+</div></pre>
+
+<p>An example JSON-LD implementation is described below, however, there are
+other ways to mark-up this information such that the context is not
+repeated.</p>
+
+<pre class="example">
+[
+ {
+ "@": "_:bnode1",
+ "a": "foaf:Person",
+ "foaf:homepage": "http://example.com/bob/",
+ "foaf:name": "Bob"
+ },
+ {
+ "@": "_:bnode2",
+ "a": "foaf:Person",
+ "foaf:homepage": "http://example.com/eve/",
+ "foaf:name": "Eve"
+ },
+ {
+ "@": "_:bnode3",
+ "a": "foaf:Person",
+ "foaf:homepage": "http://example.com/manu/",
+ "foaf:name": "Manu"
+ }
+]</pre>
+
+</div>
+
+<div id="microformats" class="section">
+<h3><span class="secno">3.2 </span>Microformats</h3>
+
+<p>The following example uses a simple Microformats hCard example to express
+how the Microformat is represented in JSON-LD.</p>
+
+<pre class="example">
+<div class="vcard">
+ <a class="url fn" href="http://tantek.com/">Tantek Çelik</a>
+</div></pre>
+
+<p>The representation of the hCard expresses the Microformat terms in the
+context and uses them directly for the <code>url</code> and <code>fn</code>
+properties. Also note that the Microformat to JSON-LD processor has
+generated the proper URL type for <code>http://tantek.com</code>.</p>
+
+<pre class="example">
+{
+ "@context":
+ {
+ "vcard": "http://microformats.org/profile/hcard#vcard",
+ "url": "http://microformats.org/profile/hcard#url",
+ "fn": "http://microformats.org/profile/hcard#fn",
+ "@coerce": { "xsd:anyURI": "url" }
+ },
+ "@": "_:bnode1",
+ "a": "vcard",
+ "url": "http://tantek.com/",
+ "fn": "Tantek Çelik"
+}</pre>
+
+</div>
+
+<div id="microdata" class="section">
+<h3><span class="secno">3.3 </span>Microdata</h3>
+
+<p>The Microdata example below expresses book information as a Microdata Work
+item.
+</p>
+
+<pre class="example">
+<dl itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Work"
+ itemid="http://purl.oreilly.com/works/45U8QJGZSQKDH8N">
+ <dt>Title</dt>
+ <dd><cite itemprop="http://purl.org/dc/terms/title">Just a Geek</cite></dd>
+ <dt>By</dt>
+ <dd><span itemprop="http://purl.org/dc/terms/creator">Wil Wheaton</span></dd>
+ <dt>Format</dt>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596007683.BOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/BOOK">
+ Print
+ </dd>
+ <dd itemprop="http://purl.org/vocab/frbr/core#realization"
+ itemscope
+ itemtype="http://purl.org/vocab/frbr/core#Expression"
+ itemid="http://purl.oreilly.com/products/9780596802189.EBOOK">
+ <link itemprop="http://purl.org/dc/terms/type" href="http://purl.oreilly.com/product-types/EBOOK">
+ Ebook
+ </dd>
+</dl></pre>
+
+<p>Note that the JSON-LD representation of the Microdata information stays
+true to the desires of the Microdata community to avoid contexts and
+instead refer to items by their full IRI.</p>
+
+<pre class="example">
+[
+ {
+ "@": "http://purl.oreilly.com/works/45U8QJGZSQKDH8N",
+ "a": "http://purl.org/vocab/frbr/core#Work",
+ "http://purl.org/dc/terms/title": "Just a Geek",
+ "http://purl.org/dc/terms/creator": "Whil Wheaton",
+ "http://purl.org/vocab/frbr/core#realization":
+ ["http://purl.oreilly.com/products/9780596007683.BOOK", "http://purl.oreilly.com/products/9780596802189.EBOOK"]
+ },
+ {
+ "@": "http://purl.oreilly.com/products/9780596007683.BOOK",
+ "a": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/BOOK"
+ },
+ {
+ "@": "http://purl.oreilly.com/products/9780596802189.EBOOK",
+ "a": "http://purl.org/vocab/frbr/core#Expression",
+ "http://purl.org/dc/terms/type": "http://purl.oreilly.com/product-types/EBOOK"
+ }
+]</pre>
+</div>
+</div>
+
+<div id="the-json-ld-processing-algorithm" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">4. </span>The JSON-LD Processing Algorithm</h2>
+
+<p>
+The processing algorithm described in this section is provided in
+order to demonstrate how one might implement a JSON-LD processor.
+Conformant implementations are only required to produce the same type and
+number of triples during the output process and are not required to
+implement the algorithm exactly as described.
+</p>
+
+<p class="issue">The Processing Algorithm is a work in progress, there are
+still major bugs in the algorithm and it's difficult to follow. It's provided
+only to very early implementers to give them an idea of how to implement a
+processor.</p>
+
+<h4 id="processing-algorithm-terms">Processing Algorithm Terms</h4>
+<ul>
+<li><dfn title="default_context" id="dfn-default_context">default context</dfn> - a context that is specified to the
+JSON-LD processing algorithm before processing begins.</li>
+<li><dfn title="default_graph" id="dfn-default_graph">default graph</dfn> - the destination graph for all triples
+generated by JSON-LD markup.</li>
+<li><dfn title="active_subject" id="dfn-active_subject">active subject</dfn> - the currently active subject that the
+processor should use when generating triples.</li>
+<li><dfn title="inherited_subject" id="dfn-inherited_subject">inherited subject</dfn> - a subject that was detected at a
+higher level of processing to be used to generate a triple once a
+<a class="tref" title="current_subject">current subject</a> is discovered or generated.</li>
+<li><dfn title="active_property" id="dfn-active_property">active property</dfn> - the currently active property that the
+processor should use when generating triples.</li>
+<li><dfn title="inherited_property" id="dfn-inherited_property">inherited property</dfn> - a property that was detected at a
+higher level of processing to be used to generate a triple once a
+<a class="tref" title="current_subject">current subject</a> is discovered or generated.</li>
+<li><dfn title="active_object" id="dfn-active_object">active object</dfn> - the currently active object that the
+processor should use when generating triples.</li>
+<li><dfn title="active_context" id="dfn-active_context">active context</dfn> - a context that is used to resolve
+CURIEs while the processing algorithm is running. The
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> is the top-most item on the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> stack.</li>
+<li><dfn title="local_context" id="dfn-local_context">local context</dfn> - a context that is specified at the JSON
+associative-array level, specified via the <code>@context</code> keyword.</li>
+<li><dfn title="list_of_incomplete_triples" id="dfn-list_of_incomplete_triples">list of incomplete triples</dfn> - A list of triples that have
+yet to have their subject set.</li>
+<li><dfn title="list_of_unprocessed_items" id="dfn-list_of_unprocessed_items">list of unprocessed items</dfn> - A list of objects that cannot be
+processed until a <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> is detected or the end of the
+current associative-array is detected.</li>
+<li><dfn title="processor_state" id="dfn-processor_state">processor state</dfn> - the processor state, which includes
+the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> stack, <a class="tref" title="current_subject">current subject</a>,
+<a class="tref" title="current_property">current property</a>,
+<a class="tref internalDFN" title="list_of_incomplete_triples" href="#dfn-list_of_incomplete_triples">list of incomplete triples</a>, and the
+<a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">list of unprocessed items</a>.
+</li></ul>
+
+<h4 id="processing-tokens-and-keywords">Processing Tokens and Keywords</h4>
+<ul>
+<li><code>@context</code> - Used to set the active context.</li>
+<li><code>@base</code> - Used to set the base IRI for all object IRIs affected
+by the active context.</li>
+<li><code>@vocab</code> - Used to set the base IRI for all property IRIs
+affected by the active context.</li>
+<li><code>@coerce</code> - Used to specify type coercion rules.</li>
+<li><code>@literal</code> - Used to specify a literal value.</li>
+<li><code>@iri</code> - Used to specify an IRI value.</li>
+<li><code>@language</code> - Used to specify the language for a literal.</li>
+<li><code>@datatype</code> - Used to specify the datatype for a literal.</li>
+<li><code>:</code> - The separator for CURIEs when used in JSON keys or
+JSON values.</li>
+<li><code>@</code> - Sets the active subjects.</li>
+<li><code>a</code> - Used to set the rdf:type of the active subjects.</li>
+</ul>
+
+<p>The algorithm below is designed for streaming (SAX-based) implementations.
+Implementers will find that non-streaming (document-based) implementations will
+be much easier to implement as full access to the JSON object model eliminates
+some of the steps that are necessary for streaming implementations. A conforming
+JSON-LD processor <em class="rfc2119" title="must">must</em> implement a processing algorithm that results in the
+same <a class="tref internalDFN" title="default_graph" href="#dfn-default_graph">default graph</a> that the following algorithm generates:</p>
+
+<ol class="algorithm">
+<li id="processing-step-default-context">Push the <a class="tref internalDFN" title="default_context" href="#dfn-default_context-1">default context</a>
+onto the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> stack.</li>
+
+<li id="processing-step-associative">If an associative array is
+detected, create a new
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a>. Copy the <a class="tref" title="current_context">current context</a> stack to
+the newly created <a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a>. Push the
+<a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> onto the newly created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a>'s <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> stack. For each
+key-value pair in the associative array, using the newly created
+<a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a> do the following:
+
+ <ol class="algorithm">
+
+ <li>If a <code>@context</code> keyword is found, the processor
+ merges each key-value pair in the <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> into the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>, overwriting
+ any duplicate values in the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>. If the
+ <code>@coerce</code> key is found, the processor
+ merges each key-value pair in the <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a>'s
+ <code>@coerce</code> mapping into the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>'s
+ <code>@coerce</code> mapping, overwriting any duplicate values in
+ the <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a>'s <code>@coerce</code> mapping.
+ Process each object in the <a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">list of unprocessed items</a>,
+ starting at <a href="#processing-subject">Step 2.2</a>.</li>
+
+ <li id="processing-associative">If the <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> has not
+ been detected, the current
+ key-value pair is placed into the <a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">list of unprocessed items</a>
+ and processing proceeds to the next key-value pair. Otherwise, if the
+ <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> is known perform the following steps:</li>
+
+ <ol class="algorithm">
+
+ <li id="processing-subject">If a <code>@</code> key is found, the
+ processor sets the <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a> to the value after
+ <a href="#markup-of-rdf-concepts">Object Processing</a> has been
+ performed.
+
+ <ol class="algorithm">
+ <li>If the <a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">inherited subject</a> and
+ <a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">inherited property</a> values are specified, generate a triple
+ using the <a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">inherited subject</a> for the subject, the
+ <a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">inherited property</a> for the property, and the
+ <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a> for the object.
+ </li>
+
+ <li>If there are any triples in the
+ <a class="tref internalDFN" title="list_of_incomplete_triples" href="#dfn-list_of_incomplete_triples">list of incomplete triples</a>, complete each triple using the
+ <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a> as the subject for each triple.
+ </li>
+ </ol>
+
+ </li>
+
+ <li>If an <code>a</code> key is found, set the <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a>
+ to <code>http://www.w3.org/1999/02/22-rdf-syntax-ns#type</code>.
+ </li>
+
+ <li>If a key that is not <code>@context</code>,
+ <code>@</code>, or <code>a</code>, set the
+ <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a> by performing
+ <a href="#markup-of-rdf-concepts">Property Processing</a> on the key.
+ </li>
+
+ <li>If the value is not an array, set the
+ <a class="tref internalDFN" title="active_object" href="#dfn-active_object">active object</a> by performing
+ <a href="#markup-of-rdf-concepts">Object Processing</a> on the value.
+ Generate a triple representing the <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a>, the
+ <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a> and the <a class="tref internalDFN" title="active_object" href="#dfn-active_object">active object</a>.</li>
+
+ <li>If the value is an associative array, then
+ process the value starting at
+ <a href="#processing-step-associative">Step 2</a>.</li>
+
+ <li>If the value is a regular array, then process the value
+ starting at
+ <a href="#processing-step-array">Step 3</a> ensuring that
+ the <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a> and the <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a>
+ are copied to a newly created <a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a>.</li>
+
+ <li>If the end of the associative array is detected, and a
+ <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a> was not discovered, then:
+
+ <ol class="algorithm">
+ <li>Generate a <a class="tref" title="blank_node_identifier">blank node identifier</a> and set it as the
+ <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a>.</li>
+
+ <li>Complete any previously incomplete triples by running all substeps
+ of <a href="#processing-subject">Step 2.2.1</a>.
+ </li>
+ </ol>
+
+ </li><li>If the end of the associative array is detected, and a
+ <a class="tref internalDFN" title="local_context" href="#dfn-local_context">local context</a> was not discovered, then assume that the
+ <a class="tref internalDFN" title="active_context" href="#dfn-active_context">active context</a> is unmodified and run all substeps of
+ <a href="#processing-associative">Step 2.2</a>
+ on the <a class="tref internalDFN" title="list_of_unprocessed_items" href="#dfn-list_of_unprocessed_items">list of unprocessed items</a>.
+ </li></ol>
+ </ol>
+ </li>
+
+ <li id="processing-step-array">If a regular array is detected,
+ process each value in the array by doing the following:
+
+ <ol class="algorithm">
+ <li>If the value is an associative array, processes per
+ <a href="#processing-step-associative">Step 2</a>, ensuring to set
+ the <a class="tref internalDFN" title="inherited_subject" href="#dfn-inherited_subject">inherited subject</a> to the <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a>
+ and the <a class="tref internalDFN" title="inherited_property" href="#dfn-inherited_property">inherited property</a> to the <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a>
+ in the newly created <a class="tref internalDFN" title="processor_state" href="#dfn-processor_state">processor state</a>.</li>
+
+ <li>If the value is not an array, set the <a class="tref internalDFN" title="active_object" href="#dfn-active_object">active object</a>
+ by performing <a href="#markup-of-rdf-concepts">Object Processing</a> on
+ the value. Generate a triple representing the <a class="tref internalDFN" title="active_subject" href="#dfn-active_subject">active subject</a>,
+ the <a class="tref internalDFN" title="active_property" href="#dfn-active_property">active property</a> and the <a class="tref internalDFN" title="active_object" href="#dfn-active_object">active object</a> and
+ place it into the <a class="tref internalDFN" title="default_graph" href="#dfn-default_graph">default graph</a>.</li>
+
+ <li>If the value is a regular array, should we support RDF
+ List/Sequence Processing?
+ <div class="issue">If the value is a regular array, should we support
+ RDF List/Sequence generation of triples? For example, would implementing
+ this be worth the more complex processing rules: "ex:orderedItems" :
+ [["one", "two", "three"]]</div></li>
+ </ol>
+ </li>
+</ol>
+
+</div>
+
+<div id="markup-of-rdf-concepts" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">5. </span>Markup of RDF Concepts</h2>
+
+<p>JSON-LD is designed to ensure that most Linked Data concepts can be marked
+up in a way that is simple to understand and author by Web developers. In many
+cases, Javascript objects can become Linked Data with the simple addition
+of a context. Since RDF is also an important sub-community of the Linked
+Data movement, it is important that all RDF concepts are well-represented
+in this specification. This section details how each RDF concept can be
+expressed in JSON-LD.</p>
+
+<div id="iris" class="section">
+<h3><span class="secno">5.1 </span>IRIs</h3>
+
+<p>Expressing IRIs are fundamental to Linked Data as that is how most subjects
+and many objects are identified. IRIs can be expressed in a variety of
+different ways in JSON-LD.</p>
+
+<ol>
+ <li>In general, an IRI is generated if it is in the key position in
+ an associative array. There are special rules for processing keys in
+ <code>@context</code> and when dealing with keys that start with the
+ <code>@</code> character.</li>
+ <li>An IRI is generated for the value specified using <code>@</code>, if
+ it is a string.</li>
+ <li>An IRI is generated for the value specified using <code>a</code>.</li>
+ <li>An IRI is generated for the value specified using the <code>@iri</code>
+ keyword.</li>
+ <li>An IRI is generated when there are <code>@coerce</code> rules in
+ effect for <code>xsd:anyURI</code> for a particular vocabulary term.</li>
+</ol>
+
+<p>An example of IRI generation for a key outside of a <code>@context</code>:
+</p>
+
+<pre class="example">
+{
+...
+ "<span class="diff">http://xmlns.com/foaf/0.1/name</span>": "Manu Sporny",
+...
+}</pre>
+
+<p>In the example above, the key
+<code>http://xmlns.com/foaf/0.1/name</code> is interpreted as an IRI, as
+opposed to being interpreted as a string..</p>
+
+<p>CURIE expansion also occurs for keys in JSON-LD:</p>
+
+<pre class="example">
+{
+...
+ "<span class="diff">foaf:name</span>": "Manu Sporny",
+...
+}</pre>
+
+<p><code>foaf:name</code> above will automatically expand out to the IRI
+<code>http://xmlns.com/foaf/0.1/name</code>.</p>
+
+<p>An IRI is generated when a value is associated with a key using
+the <code>@iri</code> keyword:</p>
+
+<pre class="example">
+{
+...
+ "foaf:homepage": { "<span class="diff">@iri</span>": "http://manu.sporny.org" }
+...
+}</pre>
+
+<p>If type coercion rules are specified in the <code>@context</code> for
+a particular vocabulary term, an IRI is generated:</p>
+
+<pre class="example">
+{<span class="diff">
+ "@context":
+ {
+ "@coerce":
+ {
+ "xsd:anyURI": "foaf:homepage"
+ }
+ }</span>
+...
+ "foaf:homepage": "http://manu.sporny.org",
+...
+}</pre>
+
+</div>
+
+<div id="identifying-the-subject" class="section">
+<h3><span class="secno">5.2 </span>Identifying the Subject</h3>
+
+<p>A subject is declared using the <code>@</code> key. The subject is the
+first piece of information needed by the JSON-LD processor in order to
+create the (subject, property, object) tuple, also known as a triple.</p>
+
+<pre class="example">
+{
+...
+ "<span class="diff">@</span>": "<span class="diff">http://example.org/people#joebob</span>",
+...
+}</pre>
+
+<p>The example above would set the subject to the IRI
+<code>http://example.org/people#joebob</code>.
+</p>
+
+</div>
+
+<div id="specifying-the-type" class="section">
+<h3><span class="secno">5.3 </span>Specifying the Type</h3>
+
+<p>The type of a particular subject can be specified using the <code>a</code>
+key. Specifying the type in this way will generate a triple of the form
+(subject, type, type-url).</p>
+
+<pre class="example">
+{
+...
+ "@": "http://example.org/people#joebob",
+ "<span class="diff">a</span>": "<span class="diff">http://xmlns.com/foaf/0.1/Person</span>",
+...
+}</pre>
+
+<p>The example above would generate the following triple
+(in N-Triples notation):</p>
+
+<pre class="example">
+<http://example.org/people#joebob>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+ <http://xmlns.com/foaf/0.1/Person> .</pre>
+
+</div>
+
+<div id="plain-literals" class="section">
+<h3><span class="secno">5.4 </span>Plain Literals</h3>
+
+<p>Regular text strings are called "plain literals" in RDF and are easily
+expressed using regular JSON strings.</p>
+
+<pre class="example">
+{
+...
+ "foaf:name": "<span class="diff">Mark Birbeck</span>",
+...
+}</pre>
+
+</div>
+
+<div id="language-specification-in-plain-literals" class="section">
+<h3><span class="secno">5.5 </span>Language Specification in Plain Literals</h3>
+
+<p>JSON-LD makes an assumption that plain literals with associated
+language encoding information is not very common when used in
+JavaScript and Web Services. Thus, it takes a little more
+effort to express plain literals in a specified language.</p>
+
+<pre class="example">
+{
+...
+ "foaf:name": <span class="diff">
+ {
+ "@literal": "花澄",
+ "@language": "ja"
+ }</span>
+...
+}</pre>
+
+<p>The example above would generate a plain literal for <em>花澄</em> and
+associate the <code>ja</code> language tag 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-literals" class="section">
+<h3><span class="secno">5.6 </span>Typed Literals</h3>
+
+<p>Literals may also be typed in JSON-LD in two ways:</p>
+
+<ol>
+ <li>By utilizing the <code>@coerce</code> keyword.</li>
+ <li>By utilizing the expanded form for specifying objects.</li>
+</ol>
+
+<p>The first example uses the <code>@coerce</code> keyword to express a
+typed literal:</p>
+
+<pre class="example">
+{<span class="diff">
+ "@context":
+ {
+ "@coerce":
+ {
+ "xsd:dateTime": "dc:modified"
+ }
+ }</span>
+...
+ "dc:modified": "2010-05-29T14:17:39+02:00",
+...
+}</pre>
+
+<p>The second example uses the expanded form for specifying objects:</p>
+
+<pre class="example">
+{
+...
+ "dc:modified": <span class="diff">
+ {
+ "@literal": "2010-05-29T14:17:39+02:00",
+ "@datatype": "xsd:dateTime"
+ }</span>
+...
+}</pre>
+
+<p>Both examples above would generate an object with the literal value of
+<code>2010-05-29T14:17:39+02:00</code> and the datatype of
+<code>http://www.w3.org/2001/XMLSchema#dateTime</code>.</p>
+
+</div>
+
+<div id="multiple-objects-for-a-single-property" class="section">
+<h3><span class="secno">5.7 </span>Multiple Objects for a Single Property</h3>
+
+<p>A JSON-LD author can express multiple triples in a compact way by using
+arrays. If a subject has multiple values for the same property, the author
+<em class="rfc2119" title="may">may</em> express each property as an array.</p>
+
+<pre class="example">
+{
+...
+ "@": "http://example.org/people#joebob",
+ "foaf:nick": <span class="diff">["joe", "bob", "jaybee"]</span>,
+...
+}</pre>
+
+<p>The markup shown above would generate the following triples:</p>
+
+<pre class="example">
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+ "joe" .
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+ "bob" .
+<http://example.org/people#joebob>
+ <http://xmlns.com/foaf/0.1/nick>
+ "jaybee" .</pre>
+
+</div>
+
+<div id="multiple-typed-literals-for-a-single-property" class="section">
+<h3><span class="secno">5.8 </span>Multiple Typed Literals for a Single Property</h3>
+
+<p>Multiple typed literals may also be expressed using the expanded
+form for objects:</p>
+
+<pre class="example">
+{
+...
+ "@": "http://example.org/articles/8",
+ "dcterms:modified": <span class="diff">
+ [
+ {
+ "@literal": "2010-05-29T14:17:39+02:00",
+ "@datatype": "xsd:dateTime"
+ },
+ {
+ "@literal": "2010-05-30T09:21:28-04:00",
+ "@datatype": "xsd:dateTime"
+ }
+ ]</span>
+...
+}</pre>
+
+<p>The markup shown above would generate the following triples:</p>
+
+<pre class="example">
+<http://example.org/articles/8>
+ <http://purl.org/dc/terms/modified>
+ "2010-05-29T14:17:39+02:00"^^http://www.w3.org/2001/XMLSchema#dateTime .
+<http://example.org/articles/8>
+ <http://purl.org/dc/terms/modified>
+ "2010-05-30T09:21:28-04:00"^^http://www.w3.org/2001/XMLSchema#dateTime .</pre>
+
+</div>
+
+<div id="blank-nodes" class="section">
+<h3><span class="secno">5.9 </span>Blank Nodes</h3>
+
+<p>At times, it becomes necessary to be able to express information without
+being able to specify the subject. Typically, this is where blank nodes come
+into play. In JSON-LD, blank node identifiers are automatically created if a
+subject is not specified using the <code>@</code> keyword. However, authors
+may name blank nodes by using the special <code>_</code> CURIE prefix.</p>
+
+<pre class="example">
+{
+...
+ "@": "<span class="diff">_:foo</span>",
+...
+}</pre>
+
+<p>The example above would set the subject to <code>_:foo</code>, which can
+then be used later on in the JSON-LD markup to refer back to the
+named blank node.
+</p>
+
+</div>
+
+</div>
+
+<div id="advanced-features" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">6. </span>Advanced Features</h2>
+
+<p>JSON-LD has a number of features that provide functionality above and beyond
+the core functionality provided by RDF. The following sections outline the
+features that are specific to JSON-LD.
+</p>
+
+<div id="automatic-typing" class="section">
+<h3><span class="secno">6.1 </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 href="#typed-literals">Typed Literals</a>:</p>
+
+<pre class="example">
+{
+...
+ // The following two values are automatically converted to a type of xsd:double
+ // and both values are equivalent to each other.
+ "measure:cups": <span class="diff">5.3</span>,
+ "measure:cups": <span class="diff">5.3e0</span>,
+ // The following value is automatically converted to a type of xsd:double as well
+ "space:astronomicUnits": <span class="diff">6.5e73</span>,
+ // The following value should never be converted to a language-native type
+ "measure:stones": <span class="diff">{ "@literal": "4.8", "@datatype": "xsd:decimal" }</span>,
+ // This value is automatically converted to having a type of xsd:integer
+ "chem:protons": <span class="diff">12</span>,
+ // This value is automatically converted to having a type of xsd:boolean
+ "sensor:active": <span class="diff">true</span>,
+...
+}</pre>
+
+<p class="note">When dealing with a number of modern programming languages,
+including JavaScript ECMA-262, there is no distinction between
+<strong>xsd:decimal</strong> and <strong>xsd:double</strong> values. That is,
+the number <code>5.3</code> and the number
+<code>5.3e0</code> are treated as if they were the same. When converting from
+JSON-LD to a language-native format and back, datatype 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 datatype 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 datatype 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">6.2 </span>Type Coercion</h3>
+
+<p>JSON-LD supports the coercion of types to ensure that the zero-edit goal of
+JSON-LD can be accomplished. Type coercion allows someone deploying JSON-LD to
+coerce and incoming or outgoing types to the proper RDF type based on a
+mapping of type IRIs to RDF types. Using type conversion, one may convert
+simple JSON data to properly typed RDF data.</p>
+
+<p>The example below demonstrates how a JSON-LD author can coerce values to
+plain literals, typed literals and IRIs.</p>
+
+<pre class="example">
+{
+ "@context":
+ {
+ "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age": "http://xmlns.com/foaf/0.1/age",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage",
+<span class="diff"> "@type":
+ {
+ "xsd:integer": "age",
+ "xsd:anyURI": "homepage",
+ }</span>
+ },
+ "name": "John Smith",
+ "age": <span class="diff">"41"</span>,
+ "homepage": <span class="diff">"http://example.org/home/"</span>
+}</pre>
+
+<p>The example above would generate the following triples:</p>
+
+<pre class="example">
+_:bnode1
+ <http://xmlns.com/foaf/0.1/name>
+ "John Smith" .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/age>
+ "41"^^http://www.w3.org/2001/XMLSchema#integer .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/homepage>
+ <http://example.org/home/> .</pre>
+
+</div>
+
+</div>
+
+<div id="best-practices" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">7. </span>Best Practices</h2>
+
+<p>The nature of Web programming allows one to use basic technologies, such as
+JSON-LD, across a variety of systems and environments. This section attempts to
+describe some of those environments and the way in which JSON-LD can be
+integrated in order to help alleviate certain development headaches.
+</p>
+
+<div id="javascript" class="section">
+<h3><span class="secno">7.1 </span>JavaScript</h3>
+
+<p class="issue">It is expected that JSON-LD will be used quite a bit in
+JavaScript environments, however, features like the expanded form for
+object values mean that using JSON-LD directly in JavaScript may be
+annoying without a middleware layer such as a simple library that
+converts JSON-LD markup before JavaScript uses it. One could say that JSON-LD
+is a good fit for the RDF API, which enables a variety of RDF-based
+Web Applications, but some don't want to require that level of functionality
+just to use JSON-LD. The group is still discussing the best way to proceed,
+so input on how JSON-LD could more easily be utilized in JavaScript
+environments would be very much appreciated.
+</p>
+</div>
+
+<div id="schema-less-databases" class="section">
+<h3><span class="secno">7.2 </span>Schema-less Databases</h3>
+
+<p class="issue">Databases such as CouchDB and MongoDB allow the creation of
+schema-less data stores. RDF is a type of schema-less data model and thus
+lends itself to databases such as CouchDB and MongoDB. Both of these databases
+can use JSON-LD as their storage format. The group needs feedback from
+CouchDB and MongoDB experts regarding the usefulness of JSON-LD in those
+environments.</p>
+</div>
+
+</div>
+
+<div id="advanced-concepts" class="section">
+
+<!-- OddPage -->
+<h2><span class="secno">8. </span>Advanced Concepts</h2>
+
+<p class="issue">There are a few advanced concepts where it is not clear
+whether or not the JSON-LD specification is going to support the complexity
+necessary to support each concept. The entire section on Advanced Concepts
+should be considered as discussion points; it is merely a list of
+possibilities where all of the benefits and drawbacks have not been explored.
+</p>
+
+<div id="vocabulary-profiles" class="section">
+<h3><span class="secno">8.1 </span>Vocabulary Profiles</h3>
+
+<p>One of the more powerful features of RDFa 1.1 Core is the ability to specify
+a collection of prefixes and terms that can be re-used by a processor to simplfy
+markup. JSON-LD provides a similar mechanism called Vocabulary Profiles, which is
+the inclusion of a context external to the JSON-LD document.</p>
+
+<p>The example below demonstrates how one may specify an external Vocabulary
+Profile. Assume the following profile exists at this imaginary URL:
+<code>http://example.org/profiles/contacts</code>.</p>
+
+<pre class="example">
+{
+ "@context":
+ {
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "name": "http://xmlns.com/foaf/0.1/name",
+ "age": "http://xmlns.com/foaf/0.1/age",
+ "homepage": "http://xmlns.com/foaf/0.1/homepage",
+ "#types":
+ {
+ "age": "xsd:integer",
+ "homepage": "xsd:anyURI",
+ }
+ }
+}</pre>
+
+<p>The profile listed above can be used in the following way:</p>
+
+<pre class="example">
+{
+ "@profile": "http://example.org/profiles/contacts",
+ "name": "John Smith",
+ "age": "41",
+ "homepage": "http://example.org/home/"
+}</pre>
+
+<p>The example above would generate the following triples:</p>
+
+<pre class="example">
+_:bnode1
+ <http://xmlns.com/foaf/0.1/name>
+ "John Smith" .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/age>
+ "41"^^http://www.w3.org/2001/XMLSchema#integer .
+_:bnode1
+ <http://xmlns.com/foaf/0.1/homepage>
+ <http://example.org/home/> .</pre>
+
+</div>
+
+<div id="disjoint-graphs" class="section">
+<h3><span class="secno">8.2 </span>Disjoint Graphs</h3>
+
+<p>When serializing an RDF graph that contains two or more sections of the
+graph which are entirely disjoint, one must use an array to express the graph
+as two graphs. This may not be acceptable to some authors, who would rather
+express the information as one graph. Since, by definition, disjoint graphs
+require there to be two top-level objects, JSON-LD utilizes a mechanism that
+allows disjoint graphs to be expressed using a single graph.</p>
+
+<p>Assume the following RDF graph:</p>
+
+<pre class="example">
+<http://example.org/people#john>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+ <http://xmlns.com/foaf/0.1/Person> .
+<http://example.org/people#jane>
+ <http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
+ <http://xmlns.com/foaf/0.1/Person> .</pre>
+
+<p>Since the two subjects are entirely disjoint with one another, it is
+impossible to express the RDF graph above using a single JSON-LD associative
+array.</p>
+
+<p>In JSON-LD, one can use the subject to express disjoint graphs as a
+single graph:</p>
+
+<pre class="example">
+{
+ "@":
+ [
+ {
+ "@": "http://example.org/people#john",
+ "a": "foaf:Person"
+ },
+ {
+ "@": "http://example.org/people#jane",
+ "a": "foaf:Person"
+ }
+ ]
+}</pre>
+
+<p>A disjoint graph could also be expressed like so:</p>
+
+<pre class="example">
+[
+ {
+ "@": "http://example.org/people#john",
+ "a": "foaf:Person"
+ },
+ {
+ "@": "http://example.org/people#jane",
+ "a": "foaf:Person"
+ }
+]</pre>
+
+</div>
+
+<div id="the-json-ld-api" class="section">
+<h3><span class="secno">8.3 </span>The JSON-LD API</h3>
+
+<p>This API provides a clean mechanism that enables developers to convert
+JSON-LD data into a format that is easier to work with in various programming
+languages.
+</p>
+
+<pre class="idl">
+<span class="idlInterface" id="idl-def-JSONLDProcessor">[<span class="extAttr">NoInterfaceObject</span>]
+interface <span class="idlInterfaceID">JSONLDProcessor</span> {
+<span class="idlMethod"> <span class="idlMethType"><a>object</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessor-toProjection-object-DOMString-jsonld-object-template-DOMString-subject-JSONLDParserCallback-callback">toProjection</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">jsonld</span></span>, <span class="idlParam">in <span class="idlParamType"><a>object</a>?</span> <span class="idlParamName">template</span></span>, <span class="idlParam">in <span class="idlParamType"><a>DOMString</a>?</span> <span class="idlParamName">subject</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a>JSONLDParserCallback</a>?</span> <span class="idlParamName">callback</span></span>);</span>
+<span class="idlMethod"> <span class="idlMethType"><a>Graph</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessor-toGraph-Graph-DOMString-jsonld-JSONLDParserCallback-callback">toGraph</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">jsonld</span></span>, <span class="idlParam">in optional <span class="idlParamType"><a>JSONLDParserCallback</a>?</span> <span class="idlParamName">callback</span></span>);</span>
+};</span>
+</pre><div id="methods" class="section"><h4><span class="secno">8.3.1 </span>Methods</h4><dl class="methods"><dt id="widl-JSONLDProcessor-toGraph-Graph-DOMString-jsonld-JSONLDParserCallback-callback"><code>toGraph</code></dt><dd>Parses JSON-LD and transforms the data into an Graph, which is
+ compatible with the RDF Interfaces API specification [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-INTERFACES">RDF-INTERFACES</a></cite>].
+ This method will
+ return <code>null</code> if there are any errors, or if the RDF Interfaces
+ API is not available for use.
+
+ <table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">jsonld</td><td class="prmType"><code><a>DOMString</a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">The JSON-LD string to parse into the RDFGraph.</td></tr><tr><td class="prmName">callback</td><td class="prmType"><code><a>JSONLDParserCallback</a></code></td><td class="prmNullTrue">✔</td><td class="prmOptTrue">✔</td><td class="prmDesc">A callback that is called whenever a processing error occurs on
+ the given JSON-LD string.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>Graph</a></code></div></dd><dt id="widl-JSONLDProcessor-toProjection-object-DOMString-jsonld-object-template-DOMString-subject-JSONLDParserCallback-callback"><code>toProjection</code></dt><dd>Parses JSON-LD text into an RDF API Projection object as specified
+ by the RDF API specification [<cite><a class="bibref" rel="biblioentry" href="#bib-RDF-API">RDF-API</a></cite>].
+ If there are any errors, <code>null</code> is returned.
+
+ <table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">jsonld</td><td class="prmType"><code><a>DOMString</a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">The JSON-LD string to parse into the Projection.</td></tr><tr><td class="prmName">template</td><td class="prmType"><code><a>object</a></code></td><td class="prmNullTrue">✔</td><td class="prmOptFalse">✘</td><td class="prmDesc">The Projection template to use when building the Projection.</td></tr><tr><td class="prmName">subject</td><td class="prmType"><code><a>DOMString</a></code></td><td class="prmNullTrue">✔</td><td class="prmOptFalse">✘</td><td class="prmDesc">The subject to use when building the Projection.</td></tr><tr><td class="prmName">callback</td><td class="prmType"><code><a>JSONLDParserCallback</a></code></td><td class="prmNullTrue">✔</td><td class="prmOptTrue">✔</td><td class="prmDesc">A callback that is called whenever a processing error occurs on
+ the given JSON-LD string.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>object</a></code></div></dd></dl></div>
+
+<p>The JSONLDParserCallback is called whenever a processing error occurs on
+input data.</p>
+
+<pre class="idl">
+<span class="idlInterface" id="idl-def-JSONLDProcessorCallback">[<span class="extAttr">NoInterfaceObject Callback</span>]
+interface <span class="idlInterfaceID">JSONLDProcessorCallback</span> {
+<span class="idlMethod"> <span class="idlMethType"><a>void</a></span> <span class="idlMethName"><a href="#widl-JSONLDProcessorCallback-error-void-DOMString-error">error</a></span> (<span class="idlParam">in <span class="idlParamType"><a>DOMString</a></span> <span class="idlParamName">error</span></span>);</span>
+};</span>
+</pre><div id="methods-1" class="section"><h4><span class="secno">8.3.2 </span>Methods</h4><dl class="methods"><dt id="widl-JSONLDProcessorCallback-error-void-DOMString-error"><code>error</code></dt><dd>This callback is invoked whenever an error occurs during processing.
+
+ <table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">error</td><td class="prmType"><code><a>DOMString</a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">A descriptive error string returned by the processor.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>void</a></code></div></dd></dl></div>
+
+<p>The following example demonstrates how to convert JSON-LD to a projection
+that is directly usable in a programming environment:
+</p>
+
+<pre class="example">
+// retrieve JSON-LD from a Web Service
+var jsonldString = fetchPerson();
+
+// This map, usually defined once per script, defines how to map incoming
+// JSON-LD to JavaScript objects
+var myTemplate = { "http://xmlns.com/foaf/0.1/name" : "name",
+ "http://xmlns.com/foaf/0.1/age" : "age",
+ "http://xmlns.com/foaf/0.1/homepage" : "homepage" };
+
+// Map the JSON-LD to a language-native object
+var person = jsonld.toProjection(jsonldString, myTemplate);
+
+// Use the language-native object
+alert(person.name + " is " + person.age + " years old. " +
+ "Their homepage is: " + person.homepage);</pre>
+
+<p>A JSON-LD Serializer is also available to map a language-native object
+to JSON-LD.
+
+</p><pre class="idl">
+<span class="idlInterface" id="idl-def-JSONLDSerializer">[<span class="extAttr">NoInterfaceObject</span>]
+interface <span class="idlInterfaceID">JSONLDSerializer</span> {
+<span class="idlMethod"> <span class="idlMethType"><a>DOMString</a></span> <span class="idlMethName"><a href="#widl-JSONLDSerializer-normalize-DOMString-object-obj">normalize</a></span> (<span class="idlParam">in <span class="idlParamType"><a>object</a></span> <span class="idlParamName">obj</span></span>);</span>
+};</span>
+</pre><div id="methods-2" class="section"><h4><span class="secno">8.3.3 </span>Methods</h4><dl class="methods"><dt id="widl-JSONLDSerializer-normalize-DOMString-object-obj"><code>normalize</code></dt><dd>Serializes a language-native object into a normalized JSON-LD string.
+ Normalization is important when performing things like equality comparison
+ and digital signature creation and verification.
+
+ <table class="parameters"><tr><th>Parameter</th><th>Type</th><th>Nullable</th><th>Optional</th><th>Description</th></tr><tr><td class="prmName">obj</td><td class="prmType"><code><a>object</a></code></td><td class="prmNullFalse">✘</td><td class="prmOptFalse">✘</td><td class="prmDesc">An associative array of key-value pairs that should be converted
+ to a JSON-LD string. It is assumed that a map already exists for the
+ data.</td></tr></table><div><em>No exceptions.</em></div><div><em>Return type: </em><code><a>DOMString</a></code></div></dd></dl></div>
+
+<h3 id="the-normalization-algorithm">The Normalization Algorithm</h3>
+
+<p class="issue">This algorithm is very rough, untested, and probably contains
+many bugs. Use at your own risk. It will change in the coming months.</p>
+
+<p>The JSON-LD normalization algorithm is as follows:</p>
+
+<ol class="algorithm">
+ <li>Remove the <code>@context</code> key and preserve it as the
+ <dfn title="transformation_map" id="dfn-transformation_map">transformation map</dfn> while running this algorithm.</li>
+ <li>For each key
+ <ol class="algorithm">
+ <li>If the key is a CURIE, expand the CURIE to an IRI using the
+ <a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">transformation map</a>.</li>
+ </ol>
+ </li>
+ <li>For each value
+ <ol class="algorithm">
+ <li>If the value should be type coerced per the
+ <a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">transformation map</a>, ensure that it is transformed to the
+ new value.</li>
+ <li>If the value is a CURIE, expand the CURIE to an IRI using the
+ <a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">transformation map</a>.</li>
+ <li>If the value is a Typed Literal and the type is a CURIE,
+ expand it to an IRI using the <a class="tref internalDFN" title="transformation_map" href="#dfn-transformation_map">transformation map</a>.</li>
+ <li>When generating the final value, use expanded object value form to
+ store all IRIs, typed literals and plain literals with language
+ information.</li>
+ </ol>
+ </li><li>Output each sorted key-value pair without any extraneous whitespace. If
+ the value is an associative array, perform this algorithm, starting
+ at step #1, recursively on the sub-tree. There should be no nesting in
+ the outputted JSON data. That is, the top-most element should be an
+ array. Each item in the array contains a single subject with a
+ corresponding array of properties in UTF-8 sort order. Any related
+ objects that are complex objects themselves should be given a top-level
+ object in the top-level array.</li>
+
+</ol>
+
+<p class="issue">Note that normalizing named blank nodes is impossible at
+present since one would have to specify a blank node naming algorithm. For
+the time being, you cannot normalize graphs that contain named blank
+nodes. However, normalizing graphs that contain non-named blank nodes
+is supported.</p>
+
+<pre class="example">
+var myObj = { "@context" : {
+ "xsd" : "http://www.w3.org/2001/XMLSchema#",
+ "name" : "http://xmlns.com/foaf/0.1/name",
+ "age" : "http://xmlns.com/foaf/0.1/age",
+ "homepage" : "http://xmlns.com/foaf/0.1/homepage",
+ "@type": {
+ "xsd:nonNegativeInteger": "age",
+ "xsd:anyURI": "homepage"
+ }
+ },
+ "name" : "Joe Jackson",
+ "age" : 42,
+ "homepage" : "http://example.org/people/joe" };
+
+// Map the language-native object to JSON-LD
+var jsonldText = jsonld.normalize(myObj);</pre>
+
+<p>After the code in the example above has executed, the
+<strong>jsonldText</strong> value will be (line-breaks added for
+readability):</p>
+
+<pre class="example">
+[{"http://xmlns.com/foaf/0.1/age":{"@datatype":"http://www.w3.org/2001/XMLSchema#nonNegativeInteger","@literal":"42"},
+"http://xmlns.com/foaf/0.1/homepage":{"@iri":"http://example.org/people/joe"},
+"http://xmlns.com/foaf/0.1/name":"Joe Jackson"}]</pre>
+
+<p>When normalizing <strong>xsd:double</strong> values, implementers <em class="rfc2119" title="must">must</em>
+ensure that the normalized value is a string. In order to generate the
+string from a <strong>double</strong> value, output equivalent to the
+<code>printf("%1.6e", value)</code> function in C <em class="rfc2119" title="must">must</em> be used where
+<strong>"%1.6e"</strong> is the string formatter and <strong>value</strong>
+is the value to be converted.</p>
+
+<p>To convert the a double value in JavaScript, implementers can use the
+following snippet of code:</p>
+
+<pre class="example">
+// the variable 'value' below is the JavaScript native double value that is to be converted
+(value).toExponential(6).replace(/(e(?:\+|-))([0-9])$/, '$10$2')</pre>
+
+<p class="note">When data needs to be normalized, JSON-LD authors should
+not use values that are going to undergo automatic conversion. This is due
+to the lossy nature of <strong>xsd:double</strong> values.</p>
+
+</div>
+
+</div>
+
+
+
+<div class="appendix section" id="the-default-context">
+
+<!-- OddPage -->
+<h2><span class="secno">A. </span>The Default Context</h2>
+
+<p>The <dfn title="default_context" id="dfn-default_context-1">default context</dfn> is provided to ensure that there are a
+reasonable set of prefixes and terms available to all JSON-LD developers.
+Mappings specified by the default context <em class="rfc2119" title="should not">should not</em> be overwritten by
+JSON-LD authors. All JSON-LD processors <em class="rfc2119" title="must">must</em> load the following context
+in as the intial context before processing JSON-LD text.</p>
+
+<pre>
+{
+ "@context":
+ {
+ "rdf": "http://www.w3.org/1999/02/22-rdf-syntax-ns#",
+ "rdfs": "http://www.w3.org/2000/01/rdf-schema#",
+ "owl": "http://www.w3.org/2002/07/owl#",
+ "xsd": "http://www.w3.org/2001/XMLSchema#",
+ "dcterms": "http://purl.org/dc/terms/",
+ "foaf": "http://xmlns.com/foaf/0.1/",
+ "cal": "http://www.w3.org/2002/12/cal/ical#",
+ "vcard": "http://www.w3.org/2006/vcard/ns# ",
+ "geo": "http://www.w3.org/2003/01/geo/wgs84_pos#",
+ "cc": "http://creativecommons.org/ns#",
+ "sioc": "http://rdfs.org/sioc/ns#",
+ "doap": "http://usefulinc.com/ns/doap#",
+ "com": "http://purl.org/commerce#",
+ "ps": "http://purl.org/payswarm#",
+ "gr": "http://purl.org/goodrelations/v1#",
+ "sig": "http://purl.org/signature#",
+ "ccard": "http://purl.org/commerce/creditcard#"
+ "@coerce":
+ {
+ "xsd:anyURI": ["foaf:homepage", "foaf:member"],
+ "xsd:integer": "foaf:age"
+ }
+ }
+}
+</pre>
+</div>
+
+
+<div class="appendix section" id="acknowledgements">
+
+<!-- OddPage -->
+<h2><span class="secno">B. </span>Acknowledgements</h2>
+
+<p>The editor would like to thank Mark Birbeck, who provided a great deal of the
+rationale and reasoning behind the JSON-LD work via his work on RDFj,
+Dave Longley who reviewed, provided feedback, and performed several
+implementation on the specification, and Ian Davis, who created RDF/JSON.
+Thanks also to Nathan Rixham, Bradley P. Allen and Richard Cyganiak for their
+input on the specification.</p>
+</div>
+
+
+
+
+<div id="references" class="appendix section">
+<!-- OddPage -->
+<h2><span class="secno">C. </span>References</h2><div id="normative-references" class="section"><h3><span class="secno">C.1 </span>Normative references</h3><dl class="bibliography"><dt id="bib-BCP47">[BCP47]</dt><dd>A. Phillips, M. Davis. <a href="http://tools.ietf.org/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-RDF-API">[RDF-API]</dt><dd>Manu Sporny, Benjamin Adrian, Nathan Rixham; et al. <a href="http://www.w3.org/2010/02/rdfa/sources/rdf-api/"><cite>RDF API</cite></a> Latest. W3C Editor's Draft. URL: <a href="http://www.w3.org/2010/02/rdfa/sources/rdf-api/">http://www.w3.org/2010/02/rdfa/sources/rdf-api/</a>
+</dd><dt id="bib-RDF-CONCEPTS">[RDF-CONCEPTS]</dt><dd>Graham Klyne; Jeremy J. Carroll. <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210"><cite>Resource Description Framework (RDF): Concepts and Abstract Syntax.</cite></a> 10 February 2004. W3C Recommendation. URL: <a href="http://www.w3.org/TR/2004/REC-rdf-concepts-20040210">http://www.w3.org/TR/2004/REC-rdf-concepts-20040210</a>
+</dd><dt id="bib-RDF-INTERFACES">[RDF-INTERFACES]</dt><dd>Nathan Rixham, Manu Sporny, Benjamin Adrian; et al. <a href="http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/"><cite>RDF Interfaces</cite></a> Latest. W3C Editor's Draft. URL: <a href="http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/">http://www.w3.org/2010/02/rdfa/sources/rdf-interfaces/</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></dl></div><div id="informative-references" class="section"><h3><span class="secno">C.2 </span>Informative references</h3><dl class="bibliography"><dt id="bib-MICRODATA">[MICRODATA]</dt><dd>Ian Hickson; et al. <a href="http://www.w3.org/TR/microdata/"><cite>Microdata</cite></a> 04 March 2010. W3C Working Draft. URL: <a href="http://www.w3.org/TR/microdata/">http://www.w3.org/TR/microdata/</a>
+</dd><dt id="bib-MICROFORMATS">[MICROFORMATS]</dt><dd><a href="http://microformats.org"><cite>Microformats</cite></a>. URL: <a href="http://microformats.org">http://microformats.org</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-20110331"><cite>RDFa Core 1.1: Syntax and processing rules for embedding RDF through attributes.</cite></a> 31 March 2011. W3C Working Draft. URL: <a href="http://www.w3.org/TR/2011/WD-rdfa-core-20110331">http://www.w3.org/TR/2011/WD-rdfa-core-20110331</a>
+</dd></dl></div></div></body></html>