[m2m-dev] QVT Declarative Project scope and OCL

[Ed Willink <ed@xxxxxxxxxxxxx>]

Hi

Following the migration of the QVT models, parsing and editors from 
GMT/UMLX the status of the OCL editing support has been unclear and the 
functionality within QVT Declarative has been creeping.

Since QVT Declarative should be a well-disciplined project, the PMC 
should be aware of and approve of this potential creep in scope.

QVT makes extensive re-use of OCL so it is important for QVT editors to 
have access to OCL editors and parsers. The OCL parser is available from 
MDT-OCL; the OCL editor support is not available from MDT-OCL and will, 
now, not be available from the OCL Tools project. The QVT Declarative 
parsers extend the MDT-OCL LPG 1 parser, analyzer and validator. The QVT 
Declarative editor framework enhances IMP to support distinct AST and 
CST views and introduces an editor meta-model so that most of the editor 
functionality is model-defined. The QVT editor models extend an OCL 
editor model.

Provision of QVT editor functionality necessitates provision of perhaps 
95% of the functionality of a purely OCL editor. The recent creep has 
been to include some of the missing 5% so that there is a pure OCL 
editor. The associated unit tests and EMOF persistence have not yet crept.

I have just started working on defining the well-formedness constraints
for QVT Core and QVT Relation in OCL and found the IMP-based OCL text 
editor invaluable (I had never written any OCL before). Genuine usage of 
the editor found many NPEs and CCEs but they were all nicely caught 
behind the scenes. Since QVT Declarative needs an OCL editor to develop 
some missing parts of the QVT specification, I submit that full OCL 
editor support is now within scope for QVT Declarative, at least until 
such time as it is appropriate to factor the OCL and AST/CST IMP editing 
enhancements into a separate OCL editor [project.

I'll make a separate MDT-dev posting highlighting the availability of an
OCL editor for MST.

	Regards

		Ed Willink