• Reiner Pope (55/55) Jul 24 2007 I've been having some fun with the 2.003 __traits, trying to make a

Reiner Pope <some address.com> writes:

I've been having some fun with the 2.003 __traits, trying to make a 
template which wraps a class in a "thunk" so that it conforms to a given 
interface. The idea is to allow:

interface Foo
{
    void run();
}

...

class Bar // doesn't inherit from Foo
{
    void run() {...} // but implements run anyway
}

...

Bar b = ... ;
Foo f = CreateWrapper!(Foo)(b);
f.run(); // calls b.run()


The problem I ran into was the inability to use aliases to implement the 
required methods of an interface. For example, the following doesn't work:

interface Bar
{
     void run();
}

class Bam : Bar
{
     void _run() {}
     alias _run run;
}

it errors at compile-time with "Bar.run isn't implemented."

I think it would make sense if this worked, and it would be useful for 
the wrapper I mentioned above, because it allows me to generate the 
methods in a separate namespace (with template mixins) and pull them in 
neatly with aliases.

Is there a reason to desire the current behaviour?

While we're at it, I thought it could also be nice to extend the alias 
behaviour to support the following:

interface Foo
{
     void run();
}

interface Bar
{
     void run();
}

class Bam : Foo, Bar
{
    void run1() {...}
    alias run1 Foo.run;

    void run2() {...}
    alias run2 Bar.run;
}

In this case, the aliases are specifically saying, "use this alias to 
implement Foo.run or Bar.run," which I think is a powerful distinction 
to be able to make.

What do you think?


   -- Reiner