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Merged
rubensworks merged 20 commits into from
Dec 5, 2025
Merged

Add missing comparison operators for triple terms #289

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5603a21
Add missing value comparison operators for triple terms
rubensworks Sep 25, 2025
e9924bd
Support triple terms in ORDER BY
rubensworks Sep 25, 2025
7213f87
Fix links to compareTripleTerm
rubensworks Sep 26, 2025
cba3ec1
Apply suggestions from code review
rubensworks Sep 26, 2025
3f20202
Link to SUBJECT, PREDICATE, and OBJECT functions
rubensworks Sep 26, 2025
189d62e
Remove obsolete sentence about triple terms in operator mapping table
rubensworks Sep 26, 2025
def10d9
Use term1/2 instead of A/B in func-compareTripleTerm
rubensworks Sep 26, 2025
bf53dac
Clarify next step in func-compareTripleTerm
rubensworks Sep 26, 2025
341047f
Apply suggestions from code review
rubensworks Oct 21, 2025
48d4d85
Fix formatting of compareTripleTerm
rubensworks Oct 21, 2025
5ef760d
Require relative ordering for IRIs and bnodes in compareTripleTerm
rubensworks Oct 21, 2025
900a4c8
Add comparison operators for triple terms to changelog
rubensworks Oct 21, 2025
e4b1cb4
Update spec/index.html
rubensworks Oct 24, 2025
ef9fac4
Update spec/index.html
rubensworks Oct 24, 2025
5ab6c98
Update spec/index.html
rubensworks Oct 25, 2025
70ea234
Remove triple term comparison from operator mapping table
rubensworks Nov 18, 2025
e5bfd34
Add example on undefined ordering of triple terms
rubensworks Nov 18, 2025
5d9c49f
Merge branch 'main' into feature/compare-triple-terms
rubensworks Nov 18, 2025
bdb6d5d
Remove explicit section references
rubensworks Nov 28, 2025
2ccda34
Update spec/index.html
rubensworks Dec 5, 2025
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107 changes: 100 additions & 7 deletions spec/index.html
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Original file line number Diff line number Diff line change
Expand Up @@ -3674,7 +3674,7 @@ <h3>ORDER BY</h3>
<p>The <a href="#op_lt">"&lt;" operator</a> (see the <a href="#OperatorMapping">Operator
Mapping</a> and <a href="#operatorExtensibility">17.3.1 Operator Extensibility</a>) defines
the relative order of pairs of <code>numerics</code>,
<code>xsd:strings</code>, <code>xsd:booleans</code> and <code>xsd:dateTimes</code>. Pairs of
<code>xsd:strings</code>, <code>xsd:booleans</code>, <code>xsd:dateTimes</code>, and <a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Terms</a>. Pairs of
IRIs are ordered by comparing them as literals with datatype <code>xsd:string</code>.</p>
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@TallTed TallTed Oct 23, 2025

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I think we need to say something about case-sensitive ordering being the norm in some environments, and case-insensitive ordering in others, as well as how to override both norms, assuming that is possible anywhere if not everywhere. I know we've said in some place(s) that lexical ordering is to be code point order, which is effectively case-sensitive, but I don't think this will suffice for all use cases. So far as I knowI believe code point order will also prove problematic when trying to compare, for instance, ä, as a single character and as a composite character (i.e., a combination of a and ¨), and in making all the as (uppercase, lowercase, with diacriticals, etc.) appear as a group and be in a predictable order within that group.

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@afs afs Oct 26, 2025 •
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"Function and operators" has fn:collation-key and https://www.w3.org/TR/xpath-functions-31/#choosing-a-collation to handle this.

(I don't see anything new to SPARQL 1.2 here so I think it's not for this PR.)

<p>SPARQL also fixes an order between some kinds of RDF terms that would not otherwise be
ordered:</p>
Expand All @@ -3683,6 +3683,7 @@ <h3>ORDER BY</h3>
<li>Blank nodes</li>
<li>IRIs</li>
<li>RDF literals</li>
<li>Triple terms</li>
</ol>
<p>SPARQL does not define a total ordering of all possible RDF terms. Here are a few examples
of pairs of terms for which the relative order is undefined:</p>
Expand Down Expand Up @@ -5418,9 +5419,7 @@ <h3>Operator Mapping</h3>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
( A.subject = B.subject ) <a href="#logical-and-operator" class="SPARQLoperator">&amp;&amp;</a><br/>
( A.predicate = B.predicate ) <a href="#logical-and-operator" class="SPARQLoperator">&amp;&amp;</a><br/>
( A.object = B.object )
<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), 0)
</td>
<td>xsd:boolean</td>
</tr>
Expand All @@ -5445,9 +5444,7 @@ <h3>Operator Mapping</h3>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
( A.subject != B.subject ) <a href="#logical-or-operator" class="SPARQLoperator">||</a><br/>
( A.predicate != B.predicate ) <a href="#logical-or-operator" class="SPARQLoperator">||</a><br/>
( A.object != B.object )
<a data-cite="XPATH-FUNCTIONS-31#func-not">fn:not</a>(<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), 0))
</td>
<td>xsd:boolean</td>
</tr>
Expand All @@ -5469,6 +5466,42 @@ <h3>Operator Mapping</h3>
</td>
<td>xsd:boolean</td>
</tr>
<tr>
<th><a href="#rRelationalExpression" title="RelationalExpression">A <span class="FAOTtoken">&lt;</span> B</a></th>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), -1)
</td>
<td>xsd:boolean</td>
</tr>
<tr>
<th><a href="#rRelationalExpression" title="RelationalExpression">A <span class="FAOTtoken">&lt;=</span> B</a></th>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
<a data-cite="XPATH-FUNCTIONS-31#func-not">fn:not</a>(<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), 1))
</td>
<td>xsd:boolean</td>
</tr>
<tr>
<th><a href="#rRelationalExpression" title="RelationalExpression">A <span class="FAOTtoken">&gt;</span> B</a></th>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), 1)
</td>
<td>xsd:boolean</td>
</tr>
<tr>
<th><a href="#rRelationalExpression" title="RelationalExpression">A <span class="FAOTtoken">&gt;=</span> B</a></th>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td><span class="type RDFterm"><a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Term</a></span></td>
<td>
<a data-cite="XPATH-FUNCTIONS-31#func-not">fn:not</a>(<a data-cite="XPATH-FUNCTIONS-31#func-numeric-equal">op:numeric-equal</a>(<a href="#func-sameTerm">compareTripleTerm</a>(A, B), -1))
</td>
<td>xsd:boolean</td>
</tr>
</tbody>
</table>
<p>
Expand Down Expand Up @@ -6084,6 +6117,66 @@ <h5>sameValue</h5>
</p>
</section>

<section id="func-compareTripleTerm">
<h5>compareTripleTerm</h5>
<pre class="prototype nohighlight">
<span class="return">xsd:integer</span> <span class="operator" style="text-transform: none;">compareTripleTerm</span> (<span class="type"><span class="type RDFterm">Triple term</span></span> <span class="name">term1</span>, <span class="type"><span class="type RDFterm">Triple term</span></span> <span class="name">term2</span>)
</pre>

<p>This function cannot be used directly in expressions. The purpose
of this function is to define the semantics of value-comparison operators on <a data-cite="RDF12-CONCEPTS#dfn-triple-term">Triple Terms</a> such as "=" and "&lt;" operator
in Section <a href="#OperatorMapping" class="sectionRef"></a>.
</p>

<p>This function returns -1, 0, 1, or throws an error.
Comparison is performed pairwise on the components of the triple terms in the order subject, predicate, object until the result is determined.
An error is thrown if comparing two components results in an error.</p>

<p>The result of this function is determined by going through the following steps.</p>

<ol>
<li>If <code>SUBJECT(A) = SUBJECT(B)</code> evaluates to true, go to the next step.
If <code>SUBJECT(A) &lt; SUBJECT(B)</code> evaluates to true, return -1.
If <code>SUBJECT(A) &gt; SUBJECT(B)</code> evaluates to true, return 1.
If any of the evalutions cause an error, raise an error.
</li>
<li>If <code>PREDICATE(A) = PREDICATE(B)</code> evaluates to true, go to the next step.
If <code>PREDICATE(A) &lt; PREDICATE(B)</code> evaluates to true, return -1.
If <code>PREDICATE(A) &gt; PREDICATE(B)</code> evaluates to true, return 1.
If any of the evalutions cause an error, raise an error.
</li>
<li>If <code>OBJECT(A) = OBJECT(B)</code> evaluates to true, return 0.
If <code>OBJECT(A) &lt; OBJECT(B)</code> evaluates to true, return -1.
If <code>OBJECT(A) &gt; OBJECT(B)</code> evaluates to true, return 1.
If any of the evalutions cause an error, raise an error.
</li>
</ol>

<p>Examples:</p>
<div class="result">
<table>
<tbody>
<tr>
<th>compareTripleTerm</th>
<th>Results</th>
</tr>
<tr>
<td><code>compareTripleTerm(&lt;&lt;(:s :p :o)&gt;&gt;, &lt;&lt;(:s :p :o)&gt;&gt;)</code></td>
<td>0</td>
</tr>
<tr>
<td><code>compareTripleTerm(&lt;&lt;(:s :p 123)&gt;&gt;, &lt;&lt;(:s :p 124)&gt;&gt;)</code></td>
<td>-1</td>
</tr>
<tr>
<td><code>compareTripleTerm(&lt;&lt;(:s :p 123)&gt;&gt;, &lt;&lt;(:s :p 122)&gt;&gt;)</code></td>
<td>1</td>
</tr>
</tbody>
</table>
</div>
</section>

<section id="func-isIRI">
<span id="func-isURI"></span>
<h5>isIRI</h5>
Expand Down
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