C# style generic interfaces with templates

[Thomas Kuehne]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Robby schrieb am 2007-01-15:
> Newish to D, so bare with me~
>
> I have a few questions surrounding Class Templates and the like if 
> anyone has time.
>
> After reading the two pages on templates (lex, and revisited) I haven't 
> seen anything regarding interfaces being templated like classes. However 
> it doesn't produce a lexical error :
>
> public interface H(T){
>     T another();
> }
> public class A(T) : H!(T)
> {
>     T t;
>     T another(){return t;}
>     void curious(){}
> }
>
> What I'm aiming for is an equivalent to c#'s generic interfaces. So I 
> can remove casting on my interface declarations.
> However, when I do this :
>   alias A!(int) a;
>   assert(a.another()==0);
>
> I get the following error : Error: need 'this' to access member another.

"a" is a type, not an instance:

# alias A!(int) a;
#
# int main(){
#    a b = new a();
#    assert(b.another() == 0);
#    return 0;
# }

> So, is there a way where I can template interfaces as I do classes to 
> give a per type based interfaces to the classes?
>
> Further on...
>
> How do I get the A class instantiated? Is that possible with templated 
> classes?
>
> public class A(T)
> {
> 	T t;
>     	this(){}
> }
>
>   alias A!(int) a;
>   a b = new a(); // doesn't work
>   A! b = new A!(int)();// doesnt either?

If the above code is at module level it will fail due to "new ..." being
a non-constant expression:

# alias A!(int) a;
# a b;
# A!(int) c;
#
# static this(){
#    b = new a();
#    c = new A!(int)();
# }

Thomas


-----BEGIN PGP SIGNATURE-----

iD8DBQFFqyrjLK5blCcjpWoRApH8AJ9QBjrMZnsy351iNeg+U8BR7N2gpQCcCLYp
XB7367b8YV5et178xFwQGHg=
=txba
-----END PGP SIGNATURE-----