#288: Added sh:SelectExpression, with test cases and TTL changes

shacl12-core/index.html

@@ -1775,7 +1775,7 @@ <h3>Node Expressions</h3>
 				</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 href="shacl12-sparql">SHACL-SPARQL</a>, computing
+						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>.
 					</p>

shacl12-sparql/index.html

@@ -383,6 +383,7 @@ <h3>Terminology</h3>
 						<dfn data-cite="rdf12-concepts#dfn-literal" data-lt="literal|literals">literal</dfn>,
 						<dfn data-cite="rdf12-concepts#dfn-blank-node" data-lt="blank node|blank nodes">blank node</dfn>,
 						<dfn data-cite="rdf12-concepts#dfn-node" data-lt="node|nodes">node</dfn> of an RDF graph,
+						<dfn data-cite="rdf12-concepts#dfn-datatype" data-lt="datatype|datatypes">datatype</dfn>,
 						<dfn data-cite="rdf12-concepts#dfn-rdf-term" data-lt="term|terms">RDF term</dfn>, and
 						<dfn data-cite="rdf12-concepts#dfn-subject" data-lt="subject|subjects">subject</dfn>,
 						<dfn data-cite="rdf12-concepts#dfn-predicate" data-lt="predicate|predicates">predicate</dfn>, and
@@ -409,6 +410,11 @@ <h3>Terminology</h3>
 						<dfn data-cite="shacl12-core#dfn-sparql-property-path" data-lt="sparql property path|sparql property paths">SPARQL property path</dfn>,
 						<dfn data-cite="shacl12-core#dfn-shapes-graph" data-lt="shapes graph">shapes graph</dfn>,
 						<dfn data-cite="shacl12-core#dfn-validators" data-lt="validator|validators">validator</dfn>,
+						<dfn data-cite="shacl12-core#dfn-node-expression" data-lt="node expression|node expresssions">node expression</dfn>,
+						<dfn data-cite="shacl12-core#dfn-node-expression-function" data-lt="node expression function|node expresssion functions">node expression function</dfn>,
+						<dfn data-cite="shacl12-core#dfn-function-name" data-lt="node expression function name">function name</dfn>,
+						<dfn data-cite="shacl12-core#dfn-key-parameter" data-lt="key parameter">key parameter</dfn>,
+						<dfn data-cite="shacl12-core#dfn-output-nodes" data-lt="output nodes">output nodes</dfn>,
 						<dfn data-cite="shacl12-core#dfn-conform" data-lt="conform|conforms">conform</dfn>,
 						<dfn data-cite="shacl12-core#dfn-failure" data-lt="failure|failures">failure</dfn>,
 						<dfn data-cite="shacl12-core#dfn-shacl-instance" data-lt="shacl instance">SHACL instance</dfn>,
@@ -1205,6 +1211,118 @@ <h3>Validation with SPARQL-based Constraint Components</h3>
 			</section>
 		</section>
 
+		<section id="sparql-node-expressions">
+			<h2>SPARQL-based Node Expressions</h2>
+			<p>
+				This section introduces <a>node expression functions</a> based on SPARQL.
+			</p>
+
+			<section id="SelectExpression">
+				<h3>Select Expressions</h3>
+				<p>
+					A <a>node expression</a> that has a <a>value</a> for <code>sh:select</code> is called a <dfn>select expression</dfn> with the <a>function name</a>
+					<code>sh:SelectExpression</code>.
+				</p>
+				<p class="syntax">
+					<span data-syntax-rule="SelectExpression-syntax">A node in an RDF graph is a <a>well-formed</a> <a>select expression</a> if it is a <a>blank node</a>
+					that is the <a>subject</a> of exactly one <a>triple</a> with <code>sh:select</code> as <a>predicate</a> and a <a>literal</a> as <a>object</a>
+					with <a>datatype</a> <code>xsd:string</code>.</span>
+					<span data-syntax-rule="SelectExpression-query-valid">Using the <a href="#sparql-prefixes">prefix handling rules</a>, the value of <code>sh:select</code> is a valid SPARQL 1.2 SELECT query.</span>
+					<span data-syntax-rule="SelectExpression-query-output-nodes">The SPARQL query derived from the value of <code>sh:select</code> <a data-cite="sparql12-query/#selectproject">projects</a> exactly one variable in the SELECT clause.</span>
+				</p>
+				<div class="def" id="LiteralExpression-evaluation">
+					<div class="def-header">EVALUATION OF SELECT EXPRESSIONS</div>
+					<p>
+						The <a>output nodes</a> of a <a>select expression</a> are the list <code>resultNodes</code> consisting of exactly the bindings of the (only)
+						variable that is projected from the SELECT clause.
+						If present in the <a>scope</a>, the value of the scope variable <code>focusNode</code> MUST be <a>pre-bound</a> as the value of the SPARQL variable <code>this</code>.
+						<br/>
+						<br/>
+						<code>eval(expr, activeGraph, scope) -> resultNodes</code>
+					</p>
+				</div>
+				<p><em>The remainder of this section is informative.</em></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 <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>.
+					</p>
+					<div class="shapes-graph">
+						<div class="turtle">
+ex:Person-fullName
+	a sh:PropertyShape ;
+	sh:name "full name" ;
+	sh:path <b>[
+		sh:prefixes &lt;http://example.org/ns&gt; ;
+		sh:select """
+			SELECT ?fullName
+			WHERE {
+				$this ex:firstName ?firstName .
+				$this ex:lastName ?lastName .
+				BIND (CONCAT(?firstName, " ", ?lastName) AS ?fullName) .
+			}
+		"""
+	]</b> ;
+	sh:datatype xsd:string .
+
+&lt;http://example.org/ns&gt;
+	a owl:Ontology ;
+	sh:declare [
+		sh:prefix "ex" ;
+		sh:namespace "http://example.org/ns#"^^xsd:anyURI ;
+	] .
+						</div>
+					</div>
+					<p>
+						This example also illustrates the use of <code>sh:prefixes</code> to insert PREFIX declarations into the beginning of the query before parsing.
+						Note that the query is executed with the current <a>focus node</a> <a>pre-bound</a> to the variable <code>this</code>.
+					</p>
+				</aside>
+				<aside class="example" title="Dynamically computed target nodes using a node expression based on a SPARQL query">
+					<p>
+						Here is an example use of a <a>select expression</a>, computing the target nodes of a shape to consist of all instances of
+						<code>ex:Person</code> where the <code>ex:age</code> is less than <code>18</code>.
+					</p>
+					<div class="shapes-graph">
+						<div class="turtle">
+ex:ChildShape
+	a sh:NodeShape ;
+	rdfs:label "Child shape" ;
+	rdfs:comment "This shape applies to all persons under 18 years of age." ;
+	sh:targetNode <b>[
+		sh:select """
+			PREFIX ex: &lt;http://example.org/ns#&gt;
+			SELECT ?person
+			WHERE {
+				?person a/rdfs:subClassOf* ex:Person .
+				?person ex:age ?age .
+				FILTER (?age &lt; 18) .
+			}
+		"""
+	]</b> .
+						</div>
+					</div>
+					<p>
+						From the following data graph, only <code>ex:Benjamin</code> is a target node.
+					</p>
+					<div class="data-graph">
+						<div class="turtle">
+<span class="focus-node-selected">ex:Benjamin</span>
+	a ex:Person ;
+	ex:age 17 .
+
+ex:Klaus
+	a ex:Person ;
+	ex:age 48 .
+
+ex:Bernd
+	a ex:Person .
+						</div>
+					</div>
+				</aside>
+			</section>
+		</section>
+
 		<div style="padding-top: 30px">
 			<h1 id="appendix" style="font-size: 160%; font-weight: bold">Appendix</h1>
 		</div>
@@ -1317,6 +1435,13 @@ <h2>Revision History</h2>
 				  <li><b>2024-02-14</b>: New work started by cloning the main SHACL spec and splitting it into SHACL Core and SHACL-SPARQL</li>
 			  </ul>
 		</section>
+
+		<section class="appendix informative" id="changes-12">
+			<h2>Changes between SHACL 1.0 SPARQL and SHACL 1.2 SPARQL Extensions</h2>
+			<ul>
+				<li>Added the <a>node expression function</a> <a href="#SelectExpression"><code>sh:SelectExpression</code></a>, see <a href="https://github.com/w3c/data-shapes/issues/288">Issue 288</a></li>
+			</ul>
+		</section>		
 
 	</body>
 

shacl12-test-suite/tests/sparql/manifest.ttl

@@ -8,4 +8,5 @@
 	mf:include <node/manifest.ttl> ;
 	mf:include <property/manifest.ttl> ;
 	mf:include <pre-binding/manifest.ttl> ;
+	mf:include <targets/manifest.ttl> ;
 	.

shacl12-test-suite/tests/sparql/property/manifest.ttl

@@ -5,5 +5,6 @@
 <>
 	a mf:Manifest ;
 	rdfs:label "Tests converted from http://datashapes.org/sh/tests/tests/sparql/property" ;
+	mf:include <property-select-001.ttl> ;
 	mf:include <sparql-001.ttl> ;
 	.

shacl12-test-suite/tests/sparql/property/property-select-001.ttl

@@ -0,0 +1,82 @@
+@prefix dash: <http://datashapes.org/dash#> .
+@prefix ex: <http://example.org/ns#> .
+@prefix mf: <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix sh: <http://www.w3.org/ns/shacl#> .
+@prefix sht: <http://www.w3.org/ns/shacl-test#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+ex:Person-fullName
+	a sh:PropertyShape ;
+  sh:targetClass ex:Person ;
+	sh:name "full name" ;
+	sh:path [
+		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:datatype xsd:string ;
+  sh:hasValue "John Muir" .
+
+<http://example.org/ns>
+	a owl:Ontology ;
+	sh:declare [
+		sh:prefix "ex" ;
+		sh:namespace "http://example.org/ns#"^^xsd:anyURI ;
+	] .
+
+ex:JohnMuir
+  a ex:Person ;
+  ex:firstName "John" ;
+  ex:lastName "Muir" .
+
+ex:JohnWayne
+  a ex:Person ;
+  ex:firstName "John" ;
+  ex:lastName "Wayne" .
+
+<>
+  rdf:type mf:Manifest ;
+  mf:entries (
+      <property-select-001>
+    ) ;
+.
+<property-select-001>
+  rdf:type sht:Validate ;
+  rdfs:label "Test of a sh:property with a sh:select expression 001" ;
+  mf:action [
+      sht:dataGraph <> ;
+      sht:shapesGraph <> ;
+    ] ;
+  mf:result [
+      rdf:type sh:ValidationReport ;
+      sh:conforms "false"^^xsd:boolean ;
+      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:resultSeverity sh:Violation ;
+          sh:sourceConstraintComponent sh:HasValueConstraintComponent ;
+          sh:sourceShape ex:Person-fullName ;
+        ] ;
+    ] ;
+  mf:status sht:approved ;
+.

shacl12-test-suite/tests/sparql/targets/manifest.ttl

@@ -0,0 +1,9 @@
+@prefix mf:      <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix sht:     <http://www.w3.org/ns/shacl-test#> .
+
+<>
+	a mf:Manifest ;
+	rdfs:label "Tests for SPARQL-based targets" ;
+	mf:include <targetNode-select-001.ttl> ;
+	.

shacl12-test-suite/tests/sparql/targets/targetNode-select-001.ttl

@@ -0,0 +1,73 @@
+@prefix dash: <http://datashapes.org/dash#> .
+@prefix ex: <http://example.org/ns#> .
+@prefix mf: <http://www.w3.org/2001/sw/DataAccess/tests/test-manifest#> .
+@prefix owl: <http://www.w3.org/2002/07/owl#> .
+@prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
+@prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
+@prefix sh: <http://www.w3.org/ns/shacl#> .
+@prefix sht: <http://www.w3.org/ns/shacl-test#> .
+@prefix xsd: <http://www.w3.org/2001/XMLSchema#> .
+
+ex:ChildShape
+	a sh:NodeShape ;
+	rdfs:label "Child shape" ;
+	rdfs:comment "This shape applies to all persons under 18 years of age." ;
+	sh:targetNode [
+		sh:select """
+			PREFIX ex: <http://example.org/ns#>
+			SELECT ?person
+			WHERE {
+				?person a/rdfs:subClassOf* ex:Person .
+				?person ex:age ?age .
+				FILTER (?age < 18) .
+			}
+		"""
+	] ;
+  sh:property ex:ChildShape-driversLicense .
+
+ex:ChildShape-driversLicense
+  a sh:PropertyShape ;
+  sh:path ex:driversLicense ;
+  sh:maxCount 0 .
+
+ex:Benjamin
+	a ex:Person ;
+  ex:driversLicense "123" ;
+	ex:age 17 .
+
+ex:Klaus
+	a ex:Person ;
+  ex:driversLicense "456" ;
+	ex:age 48 .
+
+ex:Bernd
+	a ex:Person ;
+  ex:driversLicense "789" .
+
+<>
+  rdf:type mf:Manifest ;
+  mf:entries (
+      <targetNode-select-001>
+    ) ;
+.
+<targetNode-select-001>
+  rdf:type sht:Validate ;
+  rdfs:label "Test of sh:targetNode with a sh:select expression 001" ;
+  mf:action [
+      sht:dataGraph <> ;
+      sht:shapesGraph <> ;
+    ] ;
+  mf:result [
+      rdf:type sh:ValidationReport ;
+      sh:conforms "false"^^xsd:boolean ;
+      sh:result [
+          rdf:type sh:ValidationResult ;
+          sh:focusNode ex:Benjamin ;
+          sh:resultPath ex:driversLicense ;
+          sh:resultSeverity sh:Violation ;
+          sh:sourceConstraintComponent sh:MaxCountConstraintComponent ;
+          sh:sourceShape ex:ChildShape-driversLicense ;
+        ] ;
+    ] ;
+  mf:status sht:approved ;
+.

shacl12-vocabularies/shacl-shacl.ttl

@@ -84,10 +84,6 @@ shsh:ShapeShape
 	# Shapes are either node shapes or property shapes
 	sh:xone ( shsh:NodeShapeShape shsh:PropertyShapeShape ) ;
 
-	sh:property [
-		sh:path sh:targetNode ;
-		sh:nodeKind	sh:IRIOrLiteral ;   # targetNode-nodeKind
-	] ; 
 	sh:property [
 		sh:path sh:targetClass ;
 		sh:nodeKind sh:IRI ;            # targetClass-nodeKind
@@ -409,3 +405,14 @@ shsh:EntailmentShape
 	a sh:NodeShape ;
 	sh:targetObjectsOf sh:entailment ;
 	sh:nodeKind sh:IRI .                # entailment-nodeKind
+
+shsh:SelectExpressionShape
+	a sh:NodeShape ;	# SelectExpression-syntax
+	sh:targetClass sh:SelectExpression ;
+	sh:targetSubjectsOf sh:select ;
+	sh:nodeKind sh:BlankNode ;
+	sh:property [
+		sh:datatype xsd:string ;
+		sh:maxCount 1 ;
+		sh:path sh:select ;
+	] .