EXPRESS11 — type-specializes-type is broader than AnonymousType

The EXPRESS concept ‘specialization’ can relate many different kinds of types per ISO 10303-11 clause 9.2.7. In particular, it extends to AnonymousTypes, GeneralizedTypes, EntityTypes, and SelectTypes. Except for a handful of explicit relationships among SimpleTypes, it is nominally a derived property that is used when it relates to the validity of expressions, actual parameters, actual types, etc. The ‘specializes’ attribute of AnonymousType is too general for the explicit relationships, and too narrow for the general concept in the ISO clause. If it is the intent to capture the specialization relationship between types per the ISO clause where needed, the ‘specializes’ attribute should be an attribute of ParameterType (the supertype of AnonymousType that covers all the EXPRESS cases).

It is not clear that the property is used at all, except for the instance diagrams in clause 8.17. But the generalization to ParameterType will not affect any existing uses, and it is optional. ‘specializes’ will be generalized to ParameterType specializes ParameterType.