[mdt-ocl.dev] OCL Delegate URIs

[Ed Willink <ed@xxxxxxxxxxxxx>]

Hi

The o.e.o.ecore plugin currently defines 
http://www.eclipse.org/emf/2002/Ecore/OCL to invoke the Traditional 
Ecore evaluator.
The o.e.o.examples.pivot plugin in Indigo defines 
http://www.eclipse.org/emf/2002/Ecore/OCL/Pivot to invoke the new Pivot 
evaluator.

The Helios OCLinEcore editor embeds OCL using 
http://www.eclipse.org/emf/2002/Ecore/OCL.
The Indigo OCLinEcore editor embeds OCL using 
http://www.eclipse.org/emf/2002/Ecore/OCL/Pivot.

Bug 360072 fixes problems with mismatches between URIs and evaluators.

----------------------

Since the embedded OCL concrete syntax is largely portable it would be 
good to evolve the URIs to support a user preference.

I suggest that we have two physical URIs.

o.e.o.ecore plugin changes to define 
http://www.eclipse.org/emf/2002/Ecore/OCL/LPG to invoke the Traditional 
Ecore evaluator.
o.e.o.examples.pivot plugin continues to define 
http://www.eclipse.org/emf/2002/Ecore/OCL/Pivot to invoke the new Pivot 
evaluator.

and one virtual URI

o.e.o.ui plugin instead defines 
http://www.eclipse.org/emf/2002/Ecore/OCL to invoke the workspace 
preference evaluator, which can be either Traditional or Pivot.

The OCLinEcore editor embeds OCL using a project preference URI which is 
the virtual URI by default.

In practice only the http://www.eclipse.org/emf/2002/Ecore/OCL virtual 
URI will be in use and the workspace preference redirects to a physical URI.

For standalone usage the UI plugin may not be in use so the standalone 
registrations can map the virtual URI directly to the desired evaluator.

Implementation wise this nicely avoids inter LPG/Pivot dependencies 
since the only coupling is the in the ui plugin that references physical 
URIs that are resolved by the platform to the extension point names in 
the relevant plugins.

Does this seem like a sensible evolution?

    Regards

        Ed Willink