Are TransitionGuards needed?

[mtf90]

Do we actually need the TransitionGuard as a standalone entity, or could the model be simplified if (guarded) Transitions were to directly hold a reference to the GuardExpression?

[pfg666]

Personally, I slightly prefer TransitionGuard being kept separate from GuardExpression, for the following reasons:

• it naturally captures a guard (defined by TransitionGuard) containing an expression (GuardExpression)
• we have, at least in the past, compared transition guards based on their identities, such comparison becomes problematic if we were to replace TransitionGuard by GuardExpressions (for which identity-comparison feels unintuitive)

[mtf90]

Fair enough, I can see the appeal especially of the second point.

[fhowar]

A second point would be that we may want to replace GuardExpressions by another implementation of expressions (e.g. constraints).