Generics syntax

Hi everyone,

I have been wondering whether we should change somethings in the syntax of 
generics (type parameters). Unbounded generics <T> would not be affected.

For bounded (or constrained) generics, the current syntax is <Bound T>. On the 
other hand, Java 5 has syntax <T extends Bound> to represent exactly the same 
thing. This is unfortunate, because for people familiar with Java 5, it will 
be an unnecessary burden to remember the difference. Besides, their syntax 
looks completely fine, so it's not like we have a strong reason to be 
different on this syntactic point.

While we are at it, we could as well implement wild cards (as in List<?>). 
Nice's type system is expressive enough that this can be implemented as 
syntactic sugar only.

Are there other Java 5 generics syntactic constructs that we don't support 
yet? As far as I know, the only one is

   interface Foo<T extends Foo<T>>

because we have something simpler which doesn't need these confusing recursive 
bounds:
   abstract interface Foo
;-)

(Of course, there are several generic constructs that can only be done in 
Nice: genericity on a type constructor/class and partial polymorphism using 
abstract interfaces, at least)

Comments?

As usual, if we change the syntax, there will be ample time for people to 
convert their code, with only warnings to help them do so.

Cheers,

Daniel



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