#650: Added link to VarExpression to clarify what "variable" means here #655
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| <p><em>The remainder of this section is informative.</em></p> | ||
| <p> | ||
| Note that the scope in the evaluation of expression constraints contains the variable <code>value</code> | ||
| Note that the scope in the evaluation of expression constraints contains the <a href="#VarExpression">variable</a> <code>value</code> |
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At least:
| Note that the scope in the evaluation of expression constraints contains the <a href="#VarExpression">variable</a> <code>value</code> | |
| Note that the scope in the evaluation of expression constraints contains the <a href="#dfn-var-expression">variable</a> <code>value</code> |
although this called a "var expression" not "a variable" so that seems to make it:
| Note that the scope in the evaluation of expression constraints contains the <a href="#VarExpression">variable</a> <code>value</code> | |
| Note that the scope in the evaluation of expression constraints contains the <a href="#VarExpression">var expression</a> <code>value</code> |
The definition:
A blank node that is the subject of the following properties is called a var expression with the function name shnex:VarExpression:
says the blank node is the var expression and is an RDF term.
If you want to keep it as the current design, please keep using "var expression" and then shacl12-rules can define variable. (There are only two other uses of "variable" in the node expressions doc at the moment.)
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We don't even need to talk VarExpressions at all here. The key is the term "scope". And scope is defined in SHACL 1.2 core as
<li><code>scope</code> is a map from (key) <a>nodes</a> to individual (value) <a>nodes</a>.
The empty map is written as <code>{}</code>.
So I think we can avoid the term variable in that definition and just refer to mappings in the scope, where the key in the map is the value of shnex:var of the var expression.
I guess the proper fix is then to create a deep link to the scope definition and reference that from node expressions.
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The map is from a string (taken from shnex:var) to RDF term.
If it is a node (RDF Term), then
[ shnex:var "foo" ] .
[ shnex:var "foo" ] .
is two different scope entries.
If there is no varExpression, how does a node expression
[ sparql:plus ( [ shnex:var foo" ] 1 ) ]
Something has to define
exprEval([ shnex:var "foo" ])
and that to be an error if "foo" is not in the scope, which is returning an empty list from scope lookup.
Closes #650