Darren New schrieb: > Marshall wrote: >> Also: has subtyping polymorphism or not, has parametric polymorphism or >> not. > > And covariant or contravariant.
That's actually not a design choice - if you wish to have a sound type system, all input parameters *must* be contravariant, all output parameters *must* be covariant, and all in/out parameters must be novariant. (Eiffel got this one wrong in almost all cases.) Regards, Jo -- http://mail.python.org/mailman/listinfo/python-list
