#301: sh:values and sh:defaultValue (#310)

HolgerKnublauch · ajnelson-nist · TallTed · web-flow · commit f9fcfcf6bd07 · 2025-03-13T08:39:42.000+01:00
* #288: Added sh:SelectExpression, with test cases and TTL changes * #222, #288: Update SHACL-SHACL for general NodeExpression and SelectExpression Signed-off-by: Alex Nelson <alexander.nelson@nist.gov> * #222, #288: Undo update SHACL-SHACL for general NodeExpression and SelectExpression This patch undoes commit 8632a3e. This was done manually instead of with `git revert`. Signed-off-by: Alex Nelson <alexander.nelson@nist.gov> * Update shacl12-vocabularies/shacl.ttl Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * #301: Switched node expressions from sh:path to sh:values and sh:defaultValue * Update shacl12-core/index.html Co-authored-by: Tomasz Pluskiewicz <tpluscode@users.noreply.github.com> * Apply suggestions from code review Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-sparql/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> * Moved example to after the evaluation part * Attempted to clarify that the "or" is not either-or * Update shacl12-core/index.html Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> --------- Signed-off-by: Alex Nelson <alexander.nelson@nist.gov> Co-authored-by: Alex Nelson <alexander.nelson@nist.gov> Co-authored-by: Ted Thibodeau Jr <tthibodeau@openlinksw.com> Co-authored-by: Tomasz Pluskiewicz <tpluscode@users.noreply.github.com>
diff --git a/shacl12-core/index.html b/shacl12-core/index.html
@@ -851,7 +851,7 @@ <h2>Shapes and Constraints</h2>
 						<div class="diagram-class-properties-section">
 							<div><a href="#name">sh:name</a> : xsd:string or rdf:langString</div>
 							<div><a href="#description">sh:description</a> : xsd:string or rdf:langString</div>
-							<div><a href="#defaultValue">sh:defaultValue</a> : any</div>
+							<div><a href="#syntax-rule-path-defaultValue">sh:defaultValue</a> : any</div>
 							<div><a href="#group">sh:group</a> : sh:PropertyGroup</div>
 						</div>
 						<div class="diagram-class-properties-section">
@@ -1447,25 +1447,24 @@ <h3>Property Shapes</h3>
 					<span data-syntax-rule="PropertyShape">A <dfn data-lt="property shapes">property shape</dfn> is a <a>shape</a> in the <a>shapes graph</a>
 					that is the <a>subject</a> of a <a>triple</a> that has <code>sh:path</code> as its <a>predicate</a>.</span>
 					<span data-syntax-rule="path-maxCount">A shape has at most one <a>value</a> for <code>sh:path</code>.</span>
-					<br/><br/>
-					<span data-syntax-rule="path-node">The <a>value</a> of <code>sh:path</code> in a property shape is either a <a>well-formed</a>
-					<a>SHACL property path</a> or a <a>well-formed</a> <a>node expression</a>.</span>
-					<span data-syntax-rule="path-expr-order">The syntax rules for <a>SHACL property paths</a> take precedence over <a>node expressions</a>;
-					for example, this means that an <a>IRI</a> will be interpreted as a <a>predicate path</a> instead of an <a>IRI expression</a>.</span>
-					<span data-syntax-rule="path-not-literal">The <a>value</a> of <code>sh:path</code> cannot be a <a>literal</a>.</span>
+					<span data-syntax-rule="path-node">The <a>value</a> of <code>sh:path</code> in a property shape is a <a>well-formed</a>
+					<a>SHACL property path</a>.</span>
 					<br/><br/>
 					It is recommended, but not required, for a <a>property shape</a> to be declared as a <a>SHACL instance</a> of <code>sh:PropertyShape</code>.
 					<span data-syntax-rule="PropertyShape-path-minCount"><a>SHACL instances</a> of <code>sh:PropertyShape</code> have one <a>value</a> for the property <code>sh:path</code>.</span>
+					<br/><br/>
+					<span data-syntax-rule="path-values">A <a>property shape</a> has at most one <a>value</a> for the property <code>sh:values</code> and this <a>value</a> is a <a>well-formed</a> <a>node expression</a>.</span>
+					<span data-syntax-rule="path-defaultValue">A <a>property shape</a> has at most one <a>value</a> for the property <code>sh:defaultValue</code> and this <a>value</a> is a <a>well-formed</a> <a>node expression</a>.</span>
+					<span data-syntax-rule="path-values-iri">A <a>property shape</a> can only have <a>values</a> for <code>sh:values</code> and/or <code>sh:defaultValue</code> when its <a>value</a> for <code>sh:path</code> is a <a href="#property-path-predicate">Predicate Path</a>.</span>
 				</p>
 				<p>
 					Informally, property shapes specify constraints that need to be met with respect to <a>nodes</a> that can be reached from the
-					<a>focus node</a> either by directly following a given property (specified as an <a>IRI</a>) or any other <a>SHACL property path</a>,
-					specified using <code>sh:path</code>.
+					<a>focus node</a> by either (a) directly following a given property (specified as an <a>IRI</a>), (b) directly following any other <a>SHACL property path</a>
+					(specified using <code>sh:path</code>), (c) evaluating the node expression (specified using <code>sh:values</code>),
+					or, (d) if no other values exist, evaluating the node expression (specified using <code>sh:defaultValue</code>).
 				</p>
 				<p>
-					If the <code>sh:path</code> is not a <a>well-formed</a> property path, it must be a <a>node expression</a>
-					and the constraints will be validated against the <a>output nodes</a> of this node expression.
-					Note that support for node expressions is not required by SHACL Core,
+					Note that support for <code>sh:values</code> and <code>sh:defaultValue</code> is not required by SHACL Core,
 					but is necessary for extensions such as [[shacl12-sparql]].
 				</p>
 				<p>
@@ -1514,8 +1513,9 @@ <h2>SHACL Expressions</h2>
 				SHACL Core supports such expressions in the following features:
 			</p>
 			<ul>
+				<li>Property paths can be used at <a href="#property-shapes"><code>sh:path</code></a> to derive the value nodes of a property shape.</li>
+				<li>Node expressions can be used at <a href="#property-shapes"><code>sh:values</code> and <code>sh:defaultValue</code></a> to derive the value nodes of a property shape.</li>
 				<li>Node expressions can be used at <a href="#targetNode"><code>sh:targetNode</code></a> to dynamically compute the targets of a shape.</li>
-				<li>Property paths and node expressions can be used at <a href="#property-shapes"><code>sh:path</code></a> to derive the value nodes of a property shape.</li>
 				<li>Node expressions can be used as parameter values of most <a href="#core-components">constraint components</a> to represent constraints that may be different depending on each focus node. <span class="todo">TODO: This change needs to be made still.</span></li>
 			</ul>
 
@@ -1678,21 +1678,37 @@ <h3>Node Expressions</h3>
 					Each of these parameters has an <a>IRI</a>.
 					One of these parameters can be the <dfn>key parameter</dfn> that uniquely identifies the <a>function name</a>.
 				</div>
+				<div class="def" id="node-expression-evaluation">
+					<div class="def-header">EVALUATION OF NODE EXPRESSIONS</div>
+					The <dfn>evaluation</dfn> of a node expression is defined as a function <code>eval(expr, activeGraph, scope) -> outputNodes</code>
+					where
+					<ul>
+						<li><code>expr</code> is a <a>node expression</a> that is the <a>subject</a> of <a>triples</a> where the <a>predicates</a> are the <a>node expression parameters</a>,
+							optional for any but the <a>key parameter</a> unless stated otherwise in the definition of the node expression function.</li>
+						<li><code>activeGraph</code> is a <a>graph</a>, called the <dfn>active graph</dfn>.</li>
+						<li><code>scope</code> is a map from <a href="https://www.w3.org/TR/sparql12-query/#defn_QueryVariable">variable names</a> to individual <a>nodes</a>.
+							The value of the variable <code>focusNode</code> (if it exists) is called the <dfn>input focus node</dfn>.
+						</li>
+					</ul>
+					The result of the evaluation of a node expression is a list of <a>nodes</a> (possibly empty and with duplicates) called the <dfn>output nodes</dfn>.
+					The evaluation may also result in an <dfn>evaluation failure</dfn>.
+				</div>
 				<p>
-					The following example illustrates the syntax of a node expression, used as a blank node value of <code>sh:path</code>:
+					The following example illustrates the syntax of a node expression, used as a blank node value of <code>sh:values</code>:
 				</p>
 				<aside class="example" title="A dynamically computed property using a node expression based on a SPARQL query">
 					<p>
 						Here is an example use of a node expression based on <a data-cite="shacl12-sparql#SelectExpression">SHACL-SPARQL</a>, computing
-						the values of a property shape for the property "full name" as the concatenation of <code>ex:firstName</code>,
-						a space and the <code>ex:lastName</code>.
+						the values of a property shape for the property "full name" as the concatenation of the <code>ex:firstName</code>,
+						a space, and the <code>ex:lastName</code>.
 					</p>
 					<div class="shapes-graph">
 						<div class="turtle">
 ex:Person-fullName
 	a sh:PropertyShape ;
 	sh:name "full name" ;
-	sh:path <b>[
+	sh:path ex:fullName ;
+	sh:values <b>[
 		sh:select """
 			PREFIX ex: &lt;http://example.org/ns#&gt;
 			SELECT ?fullName
@@ -1711,23 +1727,8 @@ <h3>Node Expressions</h3>
 						and the <a>function name</a> is (as defined by SHACL-SPARQL) is <code>sh:SelectExpression</code>.
 					</p>
 				</aside>
-				<div class="def" id="node-expression-evaluation">
-					<div class="def-header">EVALUATION OF NODE EXPRESSIONS</div>
-					The <dfn>evaluation</dfn> of a node expression is defined as a function <code>eval(expr, activeGraph, scope) -> outputNodes</code>
-					where
-					<ul>
-						<li><code>expr</code> is a <a>node expression</a> that is the <a>subject</a> of <a>triples</a> where the <a>predicates</a> are the <a>node expression parameters</a>,
-							optional for any but the <a>key parameter</a> unless stated otherwise in the definition of the node expression function.</li>
-						<li><code>activeGraph</code> is a <a>graph</a>, called the <dfn>active graph</dfn>.</li>
-						<li><code>scope</code> is a map from <a href="https://www.w3.org/TR/sparql12-query/#defn_QueryVariable">variable names</a> to individual <a>nodes</a>.
-							The value of the variable <code>focusNode</code> (if it exists) is called the <dfn>input focus node</dfn>.
-						</li>
-					</ul>
-					The result of the evaluation of a node expression is a list of <a>nodes</a> (possibly empty and with duplicates) called the <dfn>output nodes</dfn>.
-					The evaluation may also result in an <dfn>evaluation failure</dfn>.
-				</div>
 				<p>
-					This SHACL Core specification only defines exactly the <a>node expression functions</a> from the following two sections.
+					This SHACL Core specification only exactly defines the <a>node expression functions</a> from the following two subsections.
 					Other specifications such as [[shacl12-sparql]] introduce additional functions.
 					Therefore <a>node expressions</a> serve as an extension point of SHACL.
 					<span class="todo">TODO: Add link to shacl12-node-expr once that is stable.</span>
@@ -2089,10 +2090,13 @@ <h5>Focus node (sh:focusNode)</h5>
 					<section id="results-path">
 						<h4>Path (sh:resultPath)</h4>
 						<p>
-							Validation results may have a value for the property <code>sh:resultPath</code> pointing at a <a>well-formed</a> <a>SHACL property path</a>
-							or <a>node expression</a>.
+							Validation results may have a value for the property <code>sh:resultPath</code> pointing at a <a>well-formed</a> <a>SHACL property path</a>.
 							For results produced by a <a>property shape</a>, this <a>SHACL property path</a> is equivalent to the <a>value</a> of <code>sh:path</code> of the shape,
 							unless stated otherwise. <!-- sh:closed is an exception -->
+							If the <code>sh:path</code> <code>p</code> is a <a>blank node</a>, then the <code>sh:resultPath</code> is a "deep copy"
+							of <code>p</code> and any <a>triples</a> that can be reached by transitively traversing the <a>blank nodes</a>
+							that appear in the <a>object</a> position of these triples.
+							See the <a href="https://www.w3.org/submissions/CBD/">Concise Bounded Description</a>.
 						</p>
 					</section>
 					<section id="results-value">
@@ -2167,22 +2171,23 @@ <h4>Value Nodes of Node Shapes</h4>
 					<h4>Value Nodes of Property Shapes</h4>
 					<p>
 						For <a>property shapes</a> with a <a>value</a> for <code>sh:path</code> <code>p</code> the
-						<a>value nodes</a> are defined as follows.
-					</p>
-					<p>
-						If <code>p</code> is a <a>SHACL property path</a>, then its value nodes are the set of <a>nodes</a> in the <a>data graph</a>
-						that can be reached from the <a>focus node</a> with the <a>path mapping</a> of <code>p</code>.
-					</p>
-					<p>
-						If <code>p</code> is a <a>node expression</a>, then its value nodes are the set of <a>output nodes</a> of
-						<code>eval(p, <a>data graph</a>, scope)</code> where <code>scope</code> contains the <a>focus node</a> as value of the variable <code>focusNode</code>.
-					</p>
-					<p>
-						Unless stated otherwise, the value of <code>sh:resultPath</code> of each validation result is a "deep copy"
-						of <code>p</code> and any <a>triples</a> that can be reached by transitively traversing the <a>blank nodes</a>
-						that appear in the <a>object</a> position of these triples.
-						See the <a href="https://www.w3.org/submissions/CBD/">Concise Bounded Description</a>.
+						set of <a>value nodes</a> is produced by the following steps:
 					</p>
+					<ol>
+						<li>
+							Add all <a>nodes</a> in the <a>data graph</a> that can be reached from the <a>focus node</a> with the <a>path mapping</a> of <code>p</code>.
+						</li>
+						<li>
+							If <code>e</code> is the <a>value</a> of <code>sh:values</code> at the <a>property shape</a>,
+							then add the <a>output nodes</a> of <code>eval(e, <a>data graph</a>, scope)</code> where <code>scope</code>
+							contains the <a>focus node</a> as the value of the variable <code>focusNode</code>.
+						</li>
+						<li>
+							If the set is still empty and <code>d</code> is the <a>value</a> of <code>sh:defaultValue</code> at the <a>property shape</a>,
+							then add the <a>output nodes</a> of <code>eval(d, <a>data graph</a>, scope)</code> where <code>scope</code>
+							contains the <a>focus node</a> as the value of the variable <code>focusNode</code>.
+						</li>
+					</ol>
 				</section>
 			</section>
 		</section>
@@ -4158,16 +4163,6 @@ <h3>sh:group</h3>
 					Groups may also have an <code>sh:order</code> property to indicate
 					the relative ordering of groups within the same form.
 				</p>
-			</section>
-			<section id="defaultValue">
-				<h3>sh:defaultValue</h3>
-				<p>
-					Property shapes may have a single value for <code>sh:defaultValue</code>.
-					The default value does not have fixed semantics in SHACL,
-					but MAY be used by user interface tools to pre-populate input widgets.
-					The value type of the <code>sh:defaultValue</code> SHOULD align with
-					the specified <code>sh:datatype</code> or <code>sh:class</code> of the same shape.
-				</p>
 				<p>
 					The following example illustrates the use of these various features together.
 				</p>
@@ -4340,7 +4335,7 @@ <h2>Revision History</h2>
 		<section class="appendix informative" id="changes-12">
 			<h2>Changes between SHACL 1.0 Core and SHACL 1.2 Core</h2>
 			<ul>
-				<li>Introduced <a>node expressions</a> as an extension point to dynamically compute lists of nodes. Generalized <code>sh:targetNode</code> and <code>sh:path</code> to support node expressions.</li>
+				<li>Introduced <a>node expressions</a> as an extension point to dynamically compute lists of nodes. Generalized <code>sh:targetNode</code> and <code>sh:defaultValue</code>, and introduced <code>sh:values</code> to support node expressions.</li>
 				<li>Added the new constraint component <a href="#SingleLineConstraintComponent"><code>sh:singleLine</code></a>, see <a href="https://github.com/w3c/data-shapes/issues/177">Issue 177</a></li>
 				<li>Added the new class <a href="#ShapeClass"><code>sh:ShapeClass</code></a> for implicit class targets, see <a href="https://github.com/w3c/data-shapes/issues/212">Issue 212</a></li>
 				<li>Moved SPARQL-based validators from Core to an Appendix of SHACL-SPARQL, see <a href="https://github.com/w3c/data-shapes/issues/271">Issue 271</a></li>
diff --git a/shacl12-sparql/index.html b/shacl12-sparql/index.html
@@ -1246,14 +1246,15 @@ <h3>Select Expressions</h3>
 				<aside class="example" title="A dynamically computed property using a node expression based on a SPARQL query">
 					<p>
 						Here is an example use of a <a>select expression</a>, computing the values of a property shape for the property 
-						"full name" as the concatenation of <code>ex:firstName</code>, a space and the <code>ex:lastName</code>.
+						"full name" as the concatenation of the <code>ex:firstName</code>, a space, and the <code>ex:lastName</code>.
 					</p>
 					<div class="shapes-graph">
 						<div class="turtle">
 ex:Person-fullName
 	a sh:PropertyShape ;
 	sh:name "full name" ;
-	sh:path <b>[
+	sh:path ex:fullName ;
+	sh:values <b>[
 		sh:prefixes &lt;http://example.org/ns&gt; ;
 		sh:select """
 			SELECT ?fullName
diff --git a/shacl12-test-suite/tests/sparql/property/property-select-001.ttl b/shacl12-test-suite/tests/sparql/property/property-select-001.ttl
@@ -12,7 +12,8 @@ ex:Person-fullName
 	a sh:PropertyShape ;
   sh:targetClass ex:Person ;
 	sh:name "full name" ;
-	sh:path [
+	sh:path ex:fullName ;
+	sh:values [
 		sh:prefixes <http://example.org/ns> ;
 		sh:select """
 			SELECT ?fullName
@@ -62,17 +63,7 @@ ex:JohnWayne
       sh:result [
           rdf:type sh:ValidationResult ;
           sh:focusNode ex:JohnWayne ;
-          sh:resultPath [
-		sh:prefixes <http://example.org/ns> ;
-		sh:select """
-			SELECT ?fullName
-			WHERE {
-				$this ex:firstName ?firstName .
-				$this ex:lastName ?lastName .
-				BIND (CONCAT(?firstName, " ", ?lastName) AS ?fullName) .
-			}
-		"""
-	] ;
+          sh:resultPath ex:fullName ;
           sh:resultSeverity sh:Violation ;
           sh:sourceConstraintComponent sh:HasValueConstraintComponent ;
           sh:sourceShape ex:Person-fullName ;
