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Re: [mdt-ocl.dev] Re: Refactoring the OCL evaluation visitor
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Hi
Even more fundamental is a question/statement that Alex has raised in
a couple of threads:
Does OCL support dynamic operation dispatch?
I think it should do, but I haven't combed the specifications looking
for positive or negative
indications.
"OCL 2.1 10.3.7 OperationCallExpEval
The definition of the semantics of the operation call expression depends
on the definition of operation call execution in
the UML semantics. This is part of the UML infrastructure specification,
and will not be defined here"
UML clearly does support dynamic dispatch and OCL is struggling for
UML alignment.
I can't find anything in UML infrastructure; just an unhelpful comment
that suggests that the substitutability
of redefined operations is a semantic variation point.
Perhaps OCL has to support user choice of semantics!
The OCL AST is inadequate since in the case where dynamic dispatch is
required we need a
boolean flag to indicate whether through qualification the user has
specified exactly A::b() or
just b(). The former should not be dynamically resolved.
Regards
Ed Willink
