Re: Covariant Return Types

>Okay, but try this version:
>
>    package c;
>    interface A { }
>    interface B { }
>    A doSomething(A a) { ... }
>    B doSomething(B b) { ... }
>
>    package d;
>    import c;
>    class C implements A, B { }
>    override c.doSomething(C a) { ... }
>
>Now, does d.doSomething(C) override c.doSomething(A) or c.doSomething(B)? Notice
>in the old specialization syntax, the last line would be:
>    override c.doSomething(a@C);
>And then, we could generalize the syntax to:
>    override c.doSomething(A a@C);
>which would make it obvious that we are specializing c.doSomething(A).

For ambiguities of which method to implementation belong to can be solved using an additional type (the compiler has support for this a long time)

doSomething(C(A) a) { ...}  //add implementation for doSomething(A)
doSomething(C(B) a) { ... } //add implementation for doSomething(B)

>Also, notice that when the package name is long, it is ugly to provide many
>specializations using that syntax.

True but you can use the additional type construct in most cases.

Arjan



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