QVT13 — QVTo: Inadequate definition of "late" semantics

The specification of "late" semantics uses the "conceptually" word; a sure sign of missing semantics. It is followed by a magic null value that stores information for later use and with an unspecified trace interaction.

The interaction of "late" and implicit collect is not handled so in

generalizations := self.eSuperTypes->collect(t | t.late resolve(UML::Generalization))

the direct association of "late" with asssignment is no longer direct; the "late"s must be aggregated. Potentuially this may occur in arbitrary complexd expressions including mapping calls!

An alternate multi-pass interpretation of "late" is given.

This seems like the correct approach; an MtoM transformation from a with-late to multi-pass without-late transformation.

Inadequate definition of "late" semantics

The specification of "late" semantics uses the "conceptually" word; a sure sign of missing semantics. It is followed by a magic null value that stores information for later use and with an unspecified trace interaction.

The interaction of "late" and implicit collect is not handled so in

generalizations := self.eSuperTypes->collect(t | t.late resolve(UML::Generalization))

the direct association of "late" with asssignment is no longer direct; the "late"s must be aggregated. Potentially this may occur in arbitrary complex expressions including mapping calls!

An alternate multi-pass interpretation of "late" is given.

This seems like the correct approach; an MtoM transformation from a with-late to multi-pass without-late transformation.

Discussion

Yes, but such an MtoM is non-trivial. Needs development and testing before it can be included as part of the specification.