I'm happy to announce Metalang99 v1.12.0, Datatype99 v1.5.2, and
Metalang99 has undergone the process of refactoring and concepts
unification, e.g., now choice types are represented as tuples.
Datatype99 has one bug fix: `derive` has been made into a proper
functional macro instead of a plain identifier.
Interface99 ships with the improved syntax: `iMethod`/`defaultIMethod`
have been renamed to `vfunc`/`vfuncDefault`, added `VCALL_*` macros
for convenient virtual table calls, and a mechanism for convenient
`self` downcasting through `VSelf` & `VSELF(T)`.