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Adds support for directional language-tagged strings. (#57)
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* Adds support for directional language-tagged strings.
Fixes some references and production styles found in N-Triples.

---------

Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com>
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@gkellogg @TallTed
gkellogg and TallTed authored Oct 19, 2023
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90 changes: 61 additions & 29 deletions spec/index.html
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Expand Up @@ -86,7 +86,9 @@
<a data-cite="RDF12-CONCEPTS#dfn-subject">subject</a> or
<a data-cite="RDF12-CONCEPTS#dfn-object">object</a> of another
<a data-cite="RDF12-CONCEPTS#dfn-rdf-triple">triple</a>,
making it possible to make statements about other statements.</p>
making it possible to make statements about other statements.
RDF 1.2 N-Quads also adds support for
<a data-cite="RDF12-CONCEPTS#dfn-dir-lang-string">directional language-tagged strings</a>.</p>
</section>

<section id='sotd'>
Expand Down Expand Up @@ -243,6 +245,13 @@ <h3>RDF Literals</h3>
<p>As in N-Triples,
<a data-cite="RDF12-CONCEPTS#dfn-literal">literals</a> are used to identify values such as strings, numbers, dates.</p>

<p>Literals (Grammar production <a href="#grammar-production-literal"><code>Literal</code></a>)
have a lexical form followed by either a
<a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
(possibly including <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>),
a <a data-cite="RDF12-CONCEPTS#dfn-datatype-iri">datatype IRI</a>,
or neither.</p>

<p>The representation of the <a data-cite="RDF12-CONCEPTS#dfn-lexical-form">lexical form</a> consists of an
initial delimiter <a href="#cp-quotation-mark"><code title="quotation mark">&quot;</code></a>,
a sequence of permitted characters or numeric escape sequence or string escape sequence,
Expand All @@ -260,11 +269,17 @@ <h3>RDF Literals</h3>

<p>The corresponding <a data-cite="RDF12-CONCEPTS#dfn-lexical-form">lexical form</a>
is the characters between the delimiters, after processing any escape sequences.
If present, the <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
is preceded by an <a href="#cp-at-sign"><code title="at sign">@</code></a>.
If present, the <a href="#grammar-production-LANG_DIR" class="type langDir"><code>LANG_DIR</code></a>
terminal matches the <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
and optionally the <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>.
The <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
is preceded by an <a href="#cp-at-sign"><code title="at sign">@</code></a>,
and, if present, the <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>
is separated from the <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
by <a href="#cp-hyphen-hyphen"><code>--</code></a>.
If there is no language tag, there may be a <a data-cite="RDF12-CONCEPTS#dfn-datatype-iri">datatype IRI</a>,
preceded by <a href="#cp-double-circumflex"><code>^^</code></a>.
If there is no datatype IRI and no language tag
If there is no datatype IRI and no language tag, then
it is a <a data-cite="RDF12-CONCEPTS#dfn-simple-literal">simple literal</a>
and the datatype is <code>http://www.w3.org/2001/XMLSchema#string</code>.
</p>
Expand All @@ -276,7 +291,7 @@ <h3>RDF Blank Nodes</h3>
As in N-Triples,
<a data-cite="RDF12-CONCEPTS#dfn-blank-node">RDF blank nodes</a> are expressed as <a href="#cp-underscore-colon"><code>_:</code></a>
followed by a blank node label which is a series of name characters.
The characters in the label are built upon <a href="#grammar-production-PN_CHARS_BASE">PN_CHARS_BASE</a>,
The characters in the label are built upon <a href="#grammar-production-PN_CHARS_BASE"><code>PN_CHARS_BASE</code></a>,
liberalized as follows:
</p>
<ul>
Expand All @@ -295,8 +310,8 @@ <h3>RDF Blank Nodes</h3>
are permitted anywhere except the first character.</li>
</ul>
<p>
A fresh RDF blank node is allocated for each unique blank node label in a document.
Repeated use of the same blank node label identifies the same RDF blank node.
A fresh RDF <a data-cite="RDF12-CONCEPTS#dfn-blank-node">blank node</a> is allocated for each unique <a data-cite="RDF12-CONCEPTS#dfn-blank-node-identifier">blank node identifier</a> in a document.
Repeated use of the same <a data-cite="RDF12-CONCEPTS#dfn-blank-node-identifier">blank node identifier</a> identifies the same blank node.
</p>

<pre id="ex-bnodes" class="example ntriples" data-transform="updateExample"
Expand Down Expand Up @@ -340,7 +355,7 @@ <h2>A Canonical form of N-Quads</h2>
any of which MUST be a single <a href="#cp-space"><code title="space">space</code></a>.</li>
<li><a data-cite="RDF12-CONCEPTS#dfn-literal">Literals</a> with the
datatype <code>http://www.w3.org/2001/XMLSchema#string</code>
MUST NOT use the datatype IRI part of the <a href="#grammar-production-literal">literal</a>,
MUST NOT use the <a data-cite="RDF12-CONCEPTS#dfn-datatype-iri">datatype IRI</a> part of the <a href="#grammar-production-literal"><code>literal</code></a>,
and are represented using only <a href="#grammar-production-STRING_LITERAL_QUOTE"><code>STRING_LITERAL_QUOTE</code></a>.
</li>
<li><a href="#grammar-production-HEX"><code>HEX</code></a> MUST use only digits
Expand Down Expand Up @@ -394,7 +409,7 @@ <h2>A Canonical form of N-Quads</h2>
<a href="#canonical-quads">additional constraints</a> of Canonical N-Quads.</p>

<p>A conforming <dfn>N-Quads parser</dfn> is a system capable of
reading N-Quads documents on behalf of an application.
reading <a>N-Quads documents</a> on behalf of an application.
It makes the serialized <a data-cite="RDF12-CONCEPTS#dfn-rdf-dataset">RDF dataset</a>,
as defined in <a href="#sec-parsing" class="sectionRef"></a>,
available to the application, usually through some form of API.</p>
Expand Down Expand Up @@ -430,8 +445,7 @@ <h3>N-Quads Grammar</h3>
<h3>White Space</h3>

<p>White space (<a href="#cp-space"><code title="space">spaces</code></a>, and/or <a href="#cp-tab"><code title="horizontal tab">tabs</code></a>) is allowed outside of terminals.
Rule names below in capitals indicate where white space is significant.
</p>
Rule names in capitals below indicate where white space is significant.</p>

<p>White space is significant in the production <a href="#grammar-production-STRING_LITERAL_QUOTE"><code>STRING_LITERAL_QUOTE</code></a>.</p>

Expand Down Expand Up @@ -617,6 +631,8 @@ <h2>Selected Terminal Literal Strings</h2>
<dd>two concatenated circumflex accent characters, each having the code point <code class="codepoint">U+005E</code></dd>
<dt id="cp-underscore-colon"><code>_:</code></dt>
<dd><a href="#cp-underscore"><code title="underscore">_</code></a> followed by <a href="#cp-colon"><code title="colon">:</code></a></dd>
<dt id="cp-hyphen-hyphen"><code>--</code></dt>
<dd>two concatenated <a href="#cp-hyphen"><code title="hyphen">-</code></a> characters</dd>
</dl>
</section>
</section>
Expand Down Expand Up @@ -649,7 +665,7 @@ <h3>RDF Term Constructors</h3>
<td>
The string after <a href="#cp-underscore-colon"><code>_:</code></a>,
is a key in <a href="#bnodeLabels">bnodeLabels</a>.
If there is no corresponding blank node in the map,
If there is no corresponding <a data-cite="RDF12-CONCEPTS#dfn-blank-node">blank node</a> in the map,
one is allocated.
</td>
</tr>
Expand All @@ -661,20 +677,25 @@ <h3>RDF Term Constructors</h3>
<a data-cite="RDF12-CONCEPTS#dfn-iri">IRI</a>
</td>
<td>
The characters between &quot;&lt;&quot; and &quot;&gt;&quot; are taken,
The characters between <a href="#cp-less-than"><code title="less-than sign">&lt;</code></a>
and <a href="#cp-greater-than"><code title="greater-than sign">&gt;</code></a> are taken,
with escape sequences unescaped,
to form the IRI.
</td>
</tr>
<tr id="handle-LANGTAG">
<tr id="handle-LANG_DIR">
<td style="text-align:left;">
<a href="#grammar-production-LANGTAG" class="type langTag">LANGTAG</a>
<a href="#grammar-production-LANG_DIR" class="type langDir">LANG_DIR</a>
</td>
<td>
<a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
</td>
<td>
The characters following the <a href="#cp-at-sign"><code title="at sign">@</code></a> form the language tag.
The characters following the <a href="#cp-at-sign"><code title="at sign">@</code></a>
form the <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
and optionally the <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>,
if the matched characters include
<a href="#cp-hyphen-hyphen"><code>--</code></a>.
</td>
</tr>
<tr id="handle-STRING_LITERAL_QUOTE">
Expand All @@ -699,13 +720,21 @@ <h3>RDF Term Constructors</h3>
<td>
The literal has a <a data-cite="RDF12-CONCEPTS#dfn-lexical-form">lexical form</a> of the first rule argument,
<a href="#grammar-production-STRING_LITERAL_QUOTE" class="type lexicalForm"><code>STRING_LITERAL_QUOTE</code></a>,
and either a <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a> of <a href="#grammar-production-LANGTAG" class="type langTag"><code>LANGTAG</code></a>
or a datatype IRI of <code>iri</code>,
and either a <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
with optional <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>
from <a href="#handle-LANG_DIR" class="type langDir"><code>LANG_DIR</code></a>
or a <a data-cite="RDF12-CONCEPTS#dfn-datatype-iri">datatype IRI</a> of <code>iri</code>,
depending on which rule matched the input.
If the <a href="#grammar-production-LANGTAG" class="type langTag"><code>LANGTAG</code></a> rule matched,
the datatype is <code>rdf:langString</code>
and the language tag is <a href="#grammar-production-LANGTAG" class="type langTag"><code>LANGTAG</code></a>.
If neither a language tag nor a datatype IRI is provided,
If the <a href="#grammar-production-LANG_DIR" class="type langDir"><code>LANG_DIR</code></a> rule matched,
the <a data-cite="RDF12-CONCEPTS#dfn-language-tag">language tag</a>
and <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>
are taken from <a href=#handle-LANG_DIR class="type langDir">LANG_DIR</a>.
If there is no <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>,
the datatype is <code>rdf:langString</code>.
If there is a <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>,
the datatype is <code>rdf:dirLangString</code>.
If neither <a href="#handle-LANG_DIR" class="type langDir"><code>LANG_DIR</code></a>
nor <a data-cite="RDF12-CONCEPTS#dfn-datatype-iri">datatype IRI</a> match,
the literal has a datatype of <code>xsd:string</code>.
</td>
</tr>
Expand Down Expand Up @@ -736,8 +765,8 @@ <h3>RDF Dataset Construction</h3>
The <a href="#grammar-production-statement"><code>statement</code></a> production produces a
triple defined by the terms constructed for
<a href="#grammar-production-subject"><code>subject</code></a>,
a href="#grammar-production-predicate"><code>predicate</code></a>, and
<a href="#grammar-production-object"><code>object</code></a>>.
<a href="#grammar-production-predicate"><code>predicate</code></a>, and
<a href="#grammar-production-object"><code>object</code></a>.
This RDF triple is added to the <a data-cite="RDF12-CONCEPTS#dfn-named-graph">graph</a> labeled by
the production <a href="#grammar-production-graphLabel"><code>graphLabel</code></a>,
if no <code>graphLabel</code> is present the triple is added to the RDF dataset's default graph.</p>
Expand Down Expand Up @@ -927,17 +956,20 @@ <h2>Changes between RDF 1.1 and RDF 1.2</h2>
for <a href="#sec-grammar-ws">White space</a> and
<a href="#sec-grammar-comments">Comments</a>,
better mirroring [[RDF12-TURTLE]].</li>
<li>Updated the <a href="#grammar-production-PN_CHARS_U">PN_CHARS_U</a>
<li>Updated the <a href="#grammar-production-PN_CHARS_U"><code>PN_CHARS_U</code></a>
grammar production to be consistent with Turtle.
Formerly, <a href="#grammar-production-PN_CHARS_U">PN_CHARS_U</a>
Formerly, <a href="#grammar-production-PN_CHARS_U"><code>PN_CHARS_U</code></a>
included "`:`" in N-Triples and N-Quads, but not in Turtle nor TriG.
<a href="#grammar-production-PN_CHARS_U">PN_CHARS_U</a> is a component
of <a href="#grammar-production-PN_CHARS_U">BLANK_NODE_LABEL</a>.</li>
<li>Adds support for <a data-cite="RDF12-CONCEPTS#dfn-quoted-triple">quoted triples</a>
<a href="#grammar-production-PN_CHARS_U"><code>PN_CHARS_U</code></a> is a component
of <a href="#grammar-production-PN_CHARS_U"><code>BLANK_NODE_LABEL</code></a>.</li>
<li>Adds support for <a data-cite="RDF12-CONCEPTS#dfn-quoted-triple">quoted triples</a>
as described in <a href="#quoted-triples" class="sectionRef"></a>
with updates to <a href="#sec-parsing-terms" class="sectionRef"></a>.</li>
<li>Separated <a href="#security"></a> from <a href="#sec-mediatype"></a>
and updated language.</li>
<li>Changes the `LANGTAG` terminal production to
<a href="#grammar-production-LANG_DIR" class="type langDir"><code>LANG_DIR</code></a> to include
an optional <a data-cite="RDF12-CONCEPTS#dfn-base-direction">base direction</a>.</li>
</ul>
</section>

Expand Down
8 changes: 4 additions & 4 deletions spec/nquads-bnf.html
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Expand Up @@ -41,7 +41,7 @@
<td>[7]</td>
<td><code>literal</code></td>
<td>::=</td>
<td><a href="#grammar-production-STRING_LITERAL_QUOTE">STRING_LITERAL_QUOTE</a> <code class="grammar-paren">(</code><code class="grammar-paren">(</code>'<code class="grammar-literal">^^</code>' <a href="#grammar-production-IRIREF">IRIREF</a><code class="grammar-paren">)</code> <code class="grammar-alt">|</code> <a href="#grammar-production-LANGTAG">LANGTAG</a><code class="grammar-paren">)</code><code class="grammar-opt">?</code></td>
<td><a href="#grammar-production-STRING_LITERAL_QUOTE">STRING_LITERAL_QUOTE</a> <code class="grammar-paren">(</code><code class="grammar-paren">(</code>'<code class="grammar-literal">^^</code>' <a href="#grammar-production-IRIREF">IRIREF</a><code class="grammar-paren">)</code> <code class="grammar-alt">|</code> <a href="#grammar-production-LANG_DIR">LANG_DIR</a><code class="grammar-paren">)</code><code class="grammar-opt">?</code></td>
</tr>
<tr id="grammar-production-quotedTriple">
<td>[8]</td>
Expand All @@ -66,11 +66,11 @@ <h3 id="terminals">Productions for terminals</h3>
<td>::=</td>
<td>'<code class="grammar-literal">_:</code>' <code class="grammar-paren">(</code><a href="#grammar-production-PN_CHARS_U">PN_CHARS_U</a> <code class="grammar-alt">|</code> <code class="grammar-brac">[</code><code class="grammar-literal">0-9</code><code class="grammar-brac">]</code><code class="grammar-paren">)</code> <code class="grammar-paren">(</code><code class="grammar-paren">(</code><a href="#grammar-production-PN_CHARS">PN_CHARS</a> <code class="grammar-alt">|</code> '<code class="grammar-literal">.</code>'<code class="grammar-paren">)</code><code class="grammar-star">*</code> <a href="#grammar-production-PN_CHARS">PN_CHARS</a><code class="grammar-paren">)</code><code class="grammar-opt">?</code></td>
</tr>
<tr id="grammar-production-LANGTAG">
<tr id="grammar-production-LANG_DIR">
<td>[12]</td>
<td><code>LANGTAG</code></td>
<td><code>LANG_DIR</code></td>
<td>::=</td>
<td>'<code class="grammar-literal">@</code>' <code class="grammar-brac">[</code><code class="grammar-literal">a-zA-Z</code><code class="grammar-brac">]</code><code class="grammar-plus">+</code> <code class="grammar-paren">(</code>'<code class="grammar-literal">-</code>' <code class="grammar-brac">[</code><code class="grammar-literal">a-zA-Z0-9</code><code class="grammar-brac">]</code><code class="grammar-plus">+</code><code class="grammar-paren">)</code><code class="grammar-star">*</code></td>
<td>'<code class="grammar-literal">@</code>' <code class="grammar-brac">[</code><code class="grammar-literal">a-zA-Z</code><code class="grammar-brac">]</code><code class="grammar-plus">+</code> <code class="grammar-paren">(</code>'<code class="grammar-literal">-</code>' <code class="grammar-brac">[</code><code class="grammar-literal">a-zA-Z0-9</code><code class="grammar-brac">]</code><code class="grammar-plus">+</code><code class="grammar-paren">)</code><code class="grammar-star">*</code> <code class="grammar-paren">(</code>'<code class="grammar-literal">--</code>' <code class="grammar-brac">[</code><code class="grammar-literal">a-zA-Z</code><code class="grammar-brac">]</code><code class="grammar-plus">+</code><code class="grammar-paren">)</code><code class="grammar-opt">?</code></td>
</tr>
<tr id="grammar-production-STRING_LITERAL_QUOTE">
<td>[13]</td>
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4 changes: 2 additions & 2 deletions spec/nquads.bnf
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Expand Up @@ -4,14 +4,14 @@ subject ::= IRIREF | BLANK_NODE_LABEL | quotedTriple
predicate ::= IRIREF
object ::= IRIREF | BLANK_NODE_LABEL | literal | quotedTriple
graphLabel ::= IRIREF | BLANK_NODE_LABEL
literal ::= STRING_LITERAL_QUOTE ('^^' IRIREF | LANGTAG )?
literal ::= STRING_LITERAL_QUOTE ('^^' IRIREF | LANG_DIR )?
quotedTriple ::= '<<' subject predicate object '>>'

@terminals

IRIREF ::= '<' ([^#x00-#x20<>"{}|^`\] | UCHAR)* '>'
BLANK_NODE_LABEL ::= '_:' ( PN_CHARS_U | [0-9] ) ((PN_CHARS|'.')* PN_CHARS)?
LANGTAG ::= '@' [a-zA-Z]+ ( '-' [a-zA-Z0-9]+ )*
LANG_DIR ::= '@' [a-zA-Z]+ ( '-' [a-zA-Z0-9]+ )* ( '--' [a-zA-Z]+ )?
STRING_LITERAL_QUOTE ::= '"' ( [^#x22#x5C#xA#xD] | ECHAR | UCHAR )* '"'
UCHAR ::= ( '\u' HEX HEX HEX HEX )
| ( '\U' HEX HEX HEX HEX HEX HEX HEX HEX )
Expand Down

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