R153 - modelint/shlaer-mellor-metamodel GitHub Wiki

Association Class Reference is a T Reference or P Reference

The T and P References are broken out as subclasses to capture the constraint that an Association Class requires one of each.

There is no functional difference between either of the subclasses other than their assignment to eponymous Perspective sides.

<subclass>.(Association class, Participating class, Rnum, Domain) ->
    Association Class Reference.(Association class, Participating class, Rnum, Domain)