- VALIDATOR: no callEvels or TimeEvents are supported.
- predefined annotations.
- "isUserInteractive" for properties. 
- "excludeMe" for model elements. For example, if user interactive is set for a property or if the model element shall be excluded from code generation.

DONE: Loop (for /while) for OpaqueBehavior (algorithm and equations)
DONE: isSubActivity for activities (algorithm and equations)