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Jan 17, 2017
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This adds a @nest member to term definitions used for _transparent properties_ #453

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3f035c7
This adds a `@nest` member to term definitions used for _transparent …
gkellogg Jan 12, 2017
01ce975
Merge branch 'master' into issue-246-nesting2
gkellogg Jan 12, 2017
fbae572
Move order of "invalid @nest value" to be along with other invalid ke…
gkellogg Jan 12, 2017
bc97d88
Merge remote-tracking branch 'origin/master' into issue-246-nesting2
gkellogg Jan 13, 2017
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4 changes: 4 additions & 0 deletions spec/latest/common/terms.html
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Expand Up @@ -180,6 +180,10 @@ <h1>General Terminology</h1>
specified via the <code>@context</code> <a>keyword</a>.</dd>
<dt><dfn data-lt="named graphs">named graph</dfn></dt><dd>
A <a>linked data graph</a> that is identified by an <a>IRI</a> or <a>blank node</a>
<dt><dfn data-lt="nested properties">nested property</dfn></dt><dd>
A <a>nested property</a> is a <a>property</a> which is contained within an object referenced by
a semantically meaningless <em>nesting property</em>.
</dd>
(the <a>graph name</a>) and a <a>graph</a>.</dd>
<dt><dfn data-lt="nodes">node</dfn></dt><dd>
Every <a>node</a> is an <a>IRI</a>, a <a>blank node</a>,
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84 changes: 75 additions & 9 deletions spec/latest/json-ld-api/index.html
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Expand Up @@ -903,7 +903,7 @@ <h3>Algorithm</h3>
</li>
<li>If <em>value</em> contains the key <code>@reverse</code>:
<ol class="algorithm">
<li>If <em>value</em> contains an <code>@id</code>, member, an
<li>If <em>value</em> contains <code>@id</code> or <code>@nest</code>, members, an
<a data-link-for="JsonLdErrorCode">invalid reverse property</a>
error has been detected and processing is aborted.</li>
<li>If the value associated with the <code>@reverse</code> key
Expand Down Expand Up @@ -1020,9 +1020,18 @@ <h3>Algorithm</h3>
of <em>definition</em> to <em>language</em>.</li>
</ol>
</li>
<li class="changed">If <em>value</em> contains the key <code>@nest</code>:
<ol class="algorithm">
<li>Initialize <em>nest</em> to the value associated with the
<code>@nest</code> key, which must be a <a>string</a> and
must not be a keyword other than <code>@nest</code>. Otherwise, an
<a data-link-for="JsonLdErrorCode">invalid @nest value</a>
error has been detected and processing is aborted.</li>
</ol>
</li>
<li>If the value contains any key other than <code>@id</code>,
<code>@reverse</code>, <code>@container</code>,
<code>@context</code>, or <code>@type</code>, an
<code>@context</code>, <code class="changed">@nest</code>, or <code>@type</code>, an
<a data-link-for="JsonLdErrorCode">invalid term definition</a> error has
been detected and processing is aborted.</li>
<li>Set the <a>term definition</a> of <em>term</em> in
Expand Down Expand Up @@ -1270,7 +1279,7 @@ <h3>Algorithm</h3>
passing <a>active context</a> and the value of the
<code>@context</code> key as <a>local context</a>.</li>
<li>Initialize an empty <a>JSON object</a>, <em>result</em>.</li>
<li>For each <em>key</em> and <em>value</em> in <em>element</em>,
<li id="alg-expand-each-key-value">For each <em>key</em> and <em>value</em> in <em>element</em>,
ordered lexicographically by <em>key</em>:
<ol class="algorithm">
<li>If <em>key</em> is <code>@context</code>, continue to
Expand Down Expand Up @@ -1418,6 +1427,10 @@ <h3>Algorithm</h3>
<li>Continue with the next <em>key</em> from <em>element</em>.</li>
</ol>
</li>
<li class="changed">If <em>expanded property</em> is <code>@nest</code>,
add <em>key</em> to <em>nests</em>, initializing it to an empty <a>array</a>,
if necessary.
Continue with the next <em>key</em> from <em>element</em>.</li>
<li class="changed">When the <code>frame expansion</code> flag is set,
if <em>expanded property</em> is any other
framing keyword (<code>@explicit</code>, <code>@default</code>,
Expand Down Expand Up @@ -1559,6 +1572,22 @@ <h3>Algorithm</h3>
member of <em>result</em>.</li>
</ol>
</li>
<li class="changed">For each key <em>nesting-key</em> in <em>nests</em>
<ol class="algorithm">
<li>Set <em>nested values</em> to the value of <em>nesting-key</em>
in <em>element</em>, ensuring that it is an <a>array</a>.</li>
<li>For each <em>nested value</em> in <em>nested values</em>:
<ol class="algorithm">
<li>If <em>nested value</em> is not a <a>JSON object</a>, or any key within
<em>nested value</em> expands to <code>@value</code>, an
<a data-link-for="JsonLdErrorCode">invalid @nest value</a> error
has been detected and processing is aborted.</li>
<li>Recursively repeat <a href="#alg-expand-each-key-value">step 7</a>
using <em>nested value</em> for <em>element</em>.</li>
</ol>
</li>
</ol>
</li>
</ol>
</li>
<li>If <em>result</em> contains the key <code>@value</code>:
Expand Down Expand Up @@ -1942,7 +1971,22 @@ <h3>Algorithm</h3>
<em>expanded value</em> for <em>value</em>,
<code>true</code> for <em>vocab</em>, and
<em>inside reverse</em>.</li>
<li>If <em>result</em> does not have the key that equals
<li class="changed">If the <a>term definition</a> for <em>item active property</em>
in the <em>active context</em> has a <code>@nest</code>
member, that value (<em>nest term</em>) must be
<code>@nest</code>, or a <a>term definition</a> in the
<em>active context</em> that expands to <code>@nest</code>,
otherwise an <a data-link-for="JsonLdErrorCode">invalid @nest
value</a> error has been detected, and processing is aborted.
If <em>result</em> does not have the key that equals <em>nest
term</em>, initialize it to an empty JSON object (<em>nest
object</em>). If <em>nest object</em> does not have the key
that equals <em>item active property</em>, set this key's
value in <em>nest object</em> to an empty
<a>array</a>.Otherwise, if the key's value is not an
<a>array</a>, then set it to one containing only the
value.</li>
<li>Otherwise, if <em>result</em> does not have the key that equals
<em>item active property</em>, set this key's value in
<em>result</em> to an empty <a>array</a>. Otherwise, if
the key's value is not an <a>array</a>, then set it
Expand All @@ -1962,6 +2006,16 @@ <h3>Algorithm</h3>
<em>expanded item</em> for <em>value</em>,
<code>true</code> for <em>vocab</em>, and
<em>inside reverse</em>.</li>
<li class="changed">If the <a>term definition</a> for <em>item active property</em>
in the <em>active context</em> has a <code>@nest</code>
member, that value (<em>nest term</em>) must be
<code>@nest</code>, or a <a>term definition</a> in the
<em>active context</em> that expands to <code>@nest</code>,
otherwise an <a data-link-for="JsonLdErrorCode">invalid @nest
value</a> error has been detected, and processing is aborted.
Set <em>nest result</em> to the value of <em>nest term</em> in <em>result</em>,
initializing it to a new <a>JSON object</a>, if necessary; otherwise
set <em>nest result</em> to <em>result</em>.</li>
<li>Initialize <em>container</em> to <code>null</code>. If there
is a <a>container mapping</a> for
<em>item active property</em> in <a>active context</a>,
Expand Down Expand Up @@ -1999,7 +2053,7 @@ <h3>Algorithm</h3>
</ol>
</li>
<li>Otherwise, <em>item active property</em> must not be a key
in <em>result</em> because there cannot be two
in <em class="changed">nest result</em> because there cannot be two
<a>list objects</a> associated
with an <a>active property</a> that has a
<a>container mapping</a>; a
Expand All @@ -2013,14 +2067,17 @@ <h3>Algorithm</h3>
or <code>@type</code></span>:
<ol class="algorithm">
<li>If <em>item active property</em> is not a key in
<em>result</em>, initialize it to an empty <a>JSON object</a>.
<em class="changed">nest result</em>, initialize it to an empty <a>JSON object</a>.
Initialize <em>map object</em> to the value of <em>item active property</em>
in <em>result</em>.</li>
in <em class="changed">nest result</em>.</li>
<li>Set <em>compacted container</em> to the result of calling the
<a href="#iri-compaction">IRI Compaction algorithm</a>
passing <a>active context</a>,
<em>container</em> as <em>iri</em>, and <code>true</code>
for <em>vocab</em>.</li>
<li>Initialize <em>map key</em> to the value associated with
with the key that equals <em>container</em> in
<em>expanded item</em>.</li>
<li>If <em>container</em> is <code>@language</code> and
<em>compacted item</em> contains the key
<code>@value</code>, then set <em>compacted item</em>
Expand Down Expand Up @@ -2063,9 +2120,9 @@ <h3>Algorithm</h3>
<li>If <em>item active property</em> is not a key in
<em>result</em> then add the key-value pair,
(<em>item active property</em>-<em>compacted item</em>),
to <em>result</em>.</li>
to <em class="changed">nest result</em>.</li>
<li>Otherwise, if the value associated with the key that
equals <em>item active property</em> in <em>result</em>
equals <em>item active property</em> in <em class="changed">nest result</em>
is not an <a>array</a>, set it to a new
<a>array</a> containing only the value. Then
append <em>compacted item</em> to the value if
Expand Down Expand Up @@ -4082,6 +4139,7 @@ <h4>JsonLdErrorCode</h4>
"cyclic IRI mapping",
"invalid @id value",
"invalid @index value",
"invalid @nest value",
"invalid @reverse value",
"invalid base IRI",
"invalid container mapping",
Expand Down Expand Up @@ -4133,6 +4191,8 @@ <h4>JsonLdErrorCode</h4>
<dt><dfn>invalid @index value</dfn></dt>
<dd>An <code>@index</code> member was encountered whose value was
not a <a>string</a>.</dd>
<dt class="changed"><dfn>invalid @nest value</dfn></dt>
<dd class="changed">An invalid value for <code>@nest</code> has been found.</dd>
<dt><dfn>invalid @reverse value</dfn></dt>
<dd>An invalid value for an <code>@reverse</code> member has been detected,
i.e., the value was not a <a>JSON object</a>.</dd>
Expand Down Expand Up @@ -4242,6 +4302,12 @@ <h2>Changes since 1.0 Recommendation of 16 January 2014</h2>
<li>A new <a href="#merge-node-maps" class="sectionRef"></a> is required
for framing, to create a single graph from the <a data-lt="default graph">default</a>
and <a>named graphs</a>.</li>
<li>An <a>expanded term definition</a> can now have an
<code>@nest</code> property, which identifies a term expanding to
<code>@nest</code> which is used for containing properties using the same
<code>@nest</code> mapping. When expanding, the values of a property
expanding to <code>@nest</code> are treated as if they were contained
within the enclosing <a>node object</a> directly.</li>
<li><code>@container</code> values within an <a>expanded term definition</a> may now
include <code>@id</code> and <code>@type</code>, corresponding to <a>id maps</a> and <a>type maps</a>.</li>
</ul>
Expand Down
113 changes: 112 additions & 1 deletion spec/latest/json-ld/index.html
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Expand Up @@ -395,6 +395,8 @@ <h2>Syntax Tokens and Keywords</h2>
<a>IRI</a>. This keyword is described in <a class="sectionRef" href="#default-vocabulary"></a>.</dd>
<dt><code>@graph</code></dt><dd>Used to express a <a>graph</a>.
This keyword is described in <a class="sectionRef" href="#named-graphs"></a>.</dd>
<dt class="changed"><code>@nest</code></dt><dd class="changed">Collects a set of <a>nested properties</a> within
a <a>node object</a>.</dd>
<dt><code>:</code></dt>
<dd>The separator for JSON keys and values that use
<a>compact IRIs</a>.</dd>
Expand Down Expand Up @@ -2684,6 +2686,85 @@ <h2>Node Type Indexing</h2>
as the <code>@type</code> property of the <a>node object</a> value.</p>
</section>

<section class="informative changed">
<h2>Nested Properties</h2>

<p>Many JSON APIs separate properties from their entities using an
intermediate object; in JSON-LD these are called <a>nested properties</a>.
For example, a set of possible labels may be grouped
under a common property:</p>
<pre class="example" data-transform="updateExample"
title="Nested properties">
<!--
{
"@context": {
"skos": "http://www.w3.org/2004/02/skos/core#",
****"labels": "@nest"****,
"main_label": {"@id": "skos:prefLabel"},
"other_label": {"@id": "skos:altLabel"},
"homepage": {"@id": "http://schema.org/description", "@type": "@id"}
},
"@id": "http://example.org/myresource",
"homepage": "http://example.org",
"labels": {
"main_label": "This is the main label for my resource",
"other_label": "This is the other label"
}
}
-->
</pre>

<p>By defining <em>labels</em> using the <a>keyword</a> <code>@nest</code>,
a <a>JSON-LD processor</a> will ignore the nesting created by using the
<em>labels</em> property and process the contents as if it were declared
directly within containing object. In this case, the <em>labels</em>
property is semantically meaningless. Defining it as equivalent to
<code>@nest</code> causes it to be ignored when expanding, making it
equivalent to the following:</p>

<pre class="example" data-transform="updateExample"
title="Nested properties folded into containing object">
<!--
{
"@context": {
"skos": "http://www.w3.org/2004/02/skos/core#",
"main_label": {"@id": "skos:prefLabel"},
"other_label": {"@id": "skos:altLabel"},
"homepage": {"@id": "http://schema.org/description", "@type": "@id"}
},
"@id": "http://example.org/myresource",
"homepage": "http://example.org",
****"main_label": "This is the main label for my resource",
"other_label": "This is the other label"****
}
-->
</pre>

<p>Similarly, node definitions may contain a <code>@nest</code> property to
reference a term aliased to <code>@nest</code> which causes such
values to be nested under that aliased term.</p>
<pre class="example" data-transform="updateExample"
title="Defining property nesting">
<!--
{
"@context": {
"skos": "http://www.w3.org/2004/02/skos/core#",
****"labels": "@nest"****,
"main_label": {"@id": "skos:prefLabel", ****"@nest": "labels"****},
"other_label": {"@id": "skos:altLabel", ****"@nest": "labels"****},
"homepage": {"@id": "http://schema.org/description", "@type": "@id"}
},
"@id": "http://example.org/myresource",
"homepage": "http://example.org",
"labels": {
"main_label": "This is the main label for my resource",
"other_label": "This is the other label"
}
}
-->
</pre>
</section>

<section class="informative">
<h3>Expanded Document Form</h3>

Expand Down Expand Up @@ -3090,6 +3171,7 @@ <h2>Node Objects</h2>
<li><code>@context</code>,</li>
<li><code>@id</code>,</li>
<li><code>@graph</code>,</li>
<li class="changed"><code>@nest</code>,</li>
<li><code>@type</code>,</li>
<li><code>@reverse</code>, or</li>
<li><code>@index</code></li>
Expand Down Expand Up @@ -3145,6 +3227,12 @@ <h2>Node Objects</h2>
<a class="sectionRef" href="#data-indexing"></a> for further discussion
on <code>@index</code> values.</p>

<p class="changed">If the <a>node object</a> contains the <code>@nest</code> key,
its value MUST be an <a>JSON object</a> or an <a>array</a> of <a>JSON objects</a>
which MUST NOT include a <a>value object</a>. See
<a class="sectionRef" href="#property-nesting"></a> for further discussion
on <code>@nest</code> values.</p>

<p>Keys in a <a>node object</a> that are not
<a>keyword</a> MAY expand to an <a>absolute IRI</a>
using the <a>active context</a>. The values associated with keys that expand
Expand Down Expand Up @@ -3315,6 +3403,19 @@ <h2>Type Maps</h2>
the <code>@id</code> of the <a>node object</a> value when expanding.</p>
</section>

<section class="changed">
<h2>Property Nesting</h2>

<p>A <a>nested property</a> is used to gather <a>properties</a> of a <a>node object</a> in a separate
<a>JSON object</a>, or <a>array</a> of <a>JSON objects</a> which are not
<a>value objects</a>. It is semantically transparent and is removed
during the process of expansion. Property nesting is recursive, and
collections of nested properties may contain further nesting.</p>

<p>Semantically, nesting is treated as if the properties and values were declared directly
within the containing <a>node object</a>.</p>
</section>

<section class="normative">
<h2>Context Definitions</h2>

Expand Down Expand Up @@ -3354,7 +3455,7 @@ <h2>Context Definitions</h2>
<a>expanded term definition</a> SHOULD NOT contain any other keys.</p>

<p>If an <a>expanded term definition</a> has an <code>@reverse</code> member,
it MUST NOT have an <code>@id</code> member at the same time. If an
it MUST NOT have <code>@id</code> or <code>@nest</code> members at the same time. If an
<code>@container</code> member exists, its value MUST be <a>null</a>,
<code>@set</code>, or <code>@index</code>.</p>

Expand Down Expand Up @@ -3392,6 +3493,10 @@ <h2>Context Definitions</h2>
the definition of a term cannot depend on the definition of another term if that other
term also depends on the first term.</p>

<p>If the <a>expanded term definition</a> contains the <code>@nest</code>
<a>keyword</a>, its value MUST be either <code>@nest</code>, or a term
which expands to <code>@nest</code>.</p>

<p>See <a class="sectionRef" href="#the-context"></a> for further discussion on contexts.</p>
</section>

Expand Down Expand Up @@ -3582,6 +3687,12 @@ <h2>Changes since 1.0 Recommendation of 16 January 2014</h2>
a <a>property</a> identified with such a <a>term</a>.</li>
<li><code>@container</code> values within an <a>expanded term definition</a> may now
include <code>@id</code> and <code>@type</code>, corresponding to <a>id maps</a> and <a>type maps</a>.</li>
<li>An <a>expanded term definition</a> can now have an
<code>@nest</code> property, which identifies a term expanding to
<code>@nest</code> which is used for containing properties using the same
<code>@nest</code> mapping. When expanding, the values of a property
expanding to <code>@nest</code> are treated as if they were contained
within the enclosing <a>node object</a> directly.</li>
</ul>
</section>

Expand Down
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