Function pointer argument to function template

[Bruno Medeiros]

Tom S wrote:
> Hey there :)
> 
> I came up with this:
> 
> ----
> 
> import std.stdio;
> 
> template Deref(T) {
>         alias typeof(*T) Deref;
> }
> 
> template RetType(T) {
>         static if (is(Deref!(T) U == function)) {
>                 alias U RetType;
>         } else static assert (false);
> }
> 
> template Bar(T, U=RetType!(T)) {
>         U Bar(T t) {
>                 writefln(typeid(U));
> 
>                 // do something :P
>                 return U.init;
>         }
> }
> 
> 
> cfloat func(int a, float b) {
>         return 1.f + 0i;
> }
> 
> 
> void main() {
>         writefln(Bar(&func));
> }
> 
> 
> -- 
> Tomasz Stachowiak  /+ a.k.a. h3r3tic +/

Just for the record, here's an alternative version, smaller, but less 
flexible(because you must know the parameters of the T function, and you 
have worse error messages):


template Bar(T, U = typeof(T(0,0)) ) {
   U Bar(T t) {
     writefln(typeid(U));

     return U.init;
   }
}

cfloat func(int a, float b) {
   return 1.f + 0i;
}


void main() {
   writefln(Bar(&func));
}


-- 
Bruno Medeiros - CS/E student
http://www.prowiki.org/wiki4d/wiki.cgi?BrunoMedeiros#D