Em 28/02/14 03:44, Sven Barth escreveu:
=== code end ===
Currently this will print:
=== output begin ===
Bar
=== output end ===
If the compiler would now naively generate an implementation of
TMyGeneric with TMyType then the result would be:
=== output begin ===
Foo
=== output end ===
This must not be. So the compiler - while it might generate an
implicit TMyType implementation - must not use that implicit
implemenation if the type that is specialized with implements non
virtual methods itself. This is one of the restrictions.
Ah, now I see. "TGeneric<T: TType>" is quite different from "var T:
TType". Afaics the former is a placeholder for another type, the latter
is a placeholder for an implementation. Thanks for sharing.
Addendum: this does not exclude the compiler from trying to optimize
this if the type parameter is indeed a class type. But this will be
transparent for the user and will have a few restrictions. It does
however not change that generics aren't full types.
:/
Maybe in the near (or not so near) future, these two approaches
(templates and generics like in Java) may live together? I mean: is this
technically possible?
FPC/Delphi generics are more templates than generics. Generics are not
full types. This will not change.
Got the point. Anyway current (2.6) generics meets about 80% of my needs
and 2.8 sounds to meet about 98% =). Thanks for the really great work
with generics!
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