EXPRESS11 — No way to distinguish GenericTypes

The Class GenericType has two named instances: GENERIC and GENERIC_ENTITY. But there is no attribute in the metamodel that distinguishes these instances.

In the GenericTypes package, the two instances are distinguished only by their object-ids. It is inappropriate to assume that the Object-ids can be easily specified in an implementation.

The GenericType metaclass should have a ‘keyword’ attribute, to capture “GENERIC” and “GENERIC_ENTITY”.

Some addition to GenericType is needed for successful model exchange.
Note that the derived ParametricType has the ‘isEntity’ property for this purpose, while SimpleTypes have an ’id’ property (of type Keyword). Since the GenericType objects are parsed from EXPRESS source, it is probably best to use the ‘id: Keyword’ pattern.
This change also necessitates creating the slot values in the GenericTypes Instance package. Because the GenericTypes instance package is significantly revised by Issue 18815, the changes that resolve this Issue are incorporated into the Revised text of Issue 18815.
Revised Text:
The text changes are incorporated in Issue 18815.
Disposition: Merged