>
> Quick question: I have a function that takes an alias parameter:
>
>        struct X { ... };
>
>        void func(alias G)(object O) {
>                ...
>                X x = ...;
>                G(x);
>                ...
>        }
>
> How do I write a signature constraint that essentially specifies that G should take a parameter of type X and return void?

if ( is(typeof(G(X.init ) ) == void))

For the expression to work, G must accept an X and return a void.

On Fri, Feb 03, 2012 at 06:51:56AM +0100, Philippe Sigaud wrote:
> >
> > Quick question: I have a function that takes an alias parameter:
> >
> >        struct X { ... };
> >
> >        void func(alias G)(object O) {
> >                ...
> >                X x = ...;
> >                G(x);
> >                ...
> >        }
> >
> > How do I write a signature constraint that essentially specifies that G should take a parameter of type X and return void?
> 
> if ( is(typeof(G(X.init ) ) == void))
> 
> For the expression to work, G must accept an X and return a void.

Ah, I forgot about .init. Thanks, that's exactly what I was looking for.


T

-- 
Береги платье снову, а здоровье смолоду.

On Fri, Feb 03, 2012 at 04:50:24PM +1100, Daniel Murphy wrote:
> void func(alias G)(object O) if (is(typeof(G(O)) == void)) {

No, the problem was that G takes another type as parameter, not 'object'.


--T

> "H. S. Teoh" <hsteoh@quickfur.ath.cx> wrote in message news:mailman.295.1328245356.25230.digitalmars-d-learn@puremagic.com...
> > Quick question: I have a function that takes an alias parameter:
> >
> > struct X { ... };
> >
> > void func(alias G)(object O) {
> > ...
> > X x = ...;
> > G(x);
> > ...
> > }
> >
> > How do I write a signature constraint that essentially specifies that G should take a parameter of type X and return void?
> >
> >
> > T
> >
> > -- 
> > When solving a problem, take care that you do not become part of the problem.
> 
> 

-- 
Without geometry, life would be pointless. -- VS