QVT13 — QVTo: Standard Library return types

The objectsOf...(T) family of operations (e.g. Element::subobjectsOfKind(T), or Element::allSubobjectsOfType(T), or Model::objectsOfType(T)) returns a set of Elements.

It should be possible to infer the precise return type from the given T, i.e., return a Set(T) instead of Set(Element).

BTW, why is there no Model::objectsOfKind(T) ?

Define return type for objectsOf...(T) operations more precisely

The objectsOf...(T) family of operations (e.g. Element::subobjectsOfKind(T), or Element::allSubobjectsOfType(T), or Model::objectsOfType(T)) returns a set of Elements.

It should be possible to infer the precise return type from the given T, i.e., return a Set(T) instead of Set(Element).

BTW, why is there no Model::objectsOfKind(T) ?

Discussion

We can make the declaraions using the same approximation to a rigorous declaration as used by selectByKind in OCL 2.4.

Omission of objectsOfKInd is an easily corrected oversight.

The incorrect objectsOfKind usage by the current objectsOfType is a confusing error that gets worse when the correct operation is provided. Better to correct it.

clone and deepClone from QVT13-12 can similarly exploit a T.

The confusing wording of Model::createEmptyModel can be clarified,