ISSUE-209: Added precision to what is a shape

shacl/index.html

@@ -774,11 +774,22 @@ <h2>Shapes and Constraints</h2>
 			<section id="shapes">
 				<h3>Shapes</h3>
 				<p>
-					A <dfn data-lt="shape|shapes">shape</dfn> can be a <a>node</a> in a <a>shapes graph</a> that is
-					a <a>SHACL instance</a> of <code>sh:Shape</code>;
-					or it can be a node so that the <a>expected type</a> of the node is <code>sh:Shape</code>,
-					or a node that has a <a>value</a> for a <a>target</a> property such as <code>sh:targetClass</code> in the <a>shapes graph</a>.
+					A <dfn data-lt="shape|shapes">shape</dfn> can be a <a>node</a> in a <a>shapes graph</a>.
+					A node is a shape if and only if it fulfills either of the following conditions in the shapes graph:
 				</p>
+				<ul>
+					<li>
+						the node is a <a>SHACL instance</a> of <code>sh:Shape</code>
+					</li>
+					<li>
+						the node has the <a>expected type</a> <code>sh:Shape</code>, which is the case if
+						it is used as a value of <a>shape-expecting constraint parameters</a> such as <code>sh:shape</code>
+						(in the case of the list-valued parameters <code>sh:and</code>, <code>sh:or</code> and <code>sh:partition</code> it must be a <a>member</a> of the corresponding lists)
+					</li>
+					<li>
+						the node has a <a>value</a> for any of the <a>target</a> properties <code>sh:targetClass</code>, <code>sh:targetNode</code>, <code>sh:targetObjectsOf</code>, <code>sh:targetSubjectsOf</code> and <code>sh:target</code>
+					</li>
+				</ul>
 				<p>
 					A shape can have zero or more <a>targets</a>, <a>constraints</a> and <a>parameters</a> of <a>constraint components</a>
 					that specify how a set of nodes from the <a>data graph</a> are validated against the shape.