[news.eclipse.modeling.mdt.uml2.ocl] [OCL] Any plans on parser extensibi

["Radek Dvorak" <radek.dvorak@xxxxxxxxxxx>]

Hi,

I have few questions on topics that come into play when starting to build
other tools based on MDT OCL.

1) OCLparser extensibility
Other languages built as an extension to OCL (like QVT) could
benefit from the existing OCL grammar and generated parser and
provide only those constructs that forms the extension.
I know that EMFT newsgroup mentions that its OCL parser was not designed
with extensibility in mind and I am just asking whether this was not 
reconsidered
with respect to the new M2M project (QVT component).

2) Error recovery
Currently, only the fail-fast approach is implemented and there is no 
comprehensive diagnosing
which accumulates errors encountered during the parsing phase and also by 
the well-formedness
validation. Reporting these along with the error locations would help a lot 
in development
of complex OCL expressions.

3) Debugging (Hooking into EvaluationVisitorImpl)
There is a post in EMFT newsgroup
(http://dev.eclipse.org/newslists/news.eclipse.technology.emft/msg01547.html) 
on the possibility
to extend the evaluation visitor.
The answer here is that "operation calls or property/association-class 
navigation"
will be provided by the EvaluationEnvironment instead.
My point is that it would be useful to have a finer-grained hook into the 
evaluation
process, especially for OCL debugging support needs. In such a case, 
involving something
like EvaluationVisitor interface seems to me a more suitable alternative to 
be used when implementing
a DebugEvent aware OCL evaluation (unless debugging is gonna be specially 
handled in MDT OCL itself ;-))).


Regards,
/Radek