template alias that includes a parameter

[Timoses]

On Sunday, 1 July 2018 at 11:55:15 UTC, Simen Kjærås wrote:
> On Sunday, 1 July 2018 at 09:46:55 UTC, Timoses wrote:
>> Would be nice if std.meta.ApplyLeft did the job here.. Is 
>> there no way of achieving that?
> [snip]
>> Would have to find a way to determine whether Template would 
>> resolve to a function or not. Can't find anything in Traits[1] 
>> or std.traits[2]. Template inspection looks rather limited : /.
>
> It is, but for a fairly good reason. This is perfectly valid D:
>
> template foo(int n) {
>     static if (n == 0) {
>         struct foo {}
>     } else static if (n == 1) {
>         enum foo = 24;
>     } else {
>         void foo() {}
>     }
> }
>
> Given an uninstantiated foo, you can't know if it'll resolve to 
> a function or not, so I guess some version of the template I 
> wrote could be added to Phobos as ApplyLeftFn or something.

Aw, okay, then that won't work.

Still, this looks like it should work:

     void foo(F, T)(T param) { writeln("Called with type: ", 
T.stringof); }
     alias tfoo = ApplyLeft!(foo, int);

     tfoo!string("hi");
     // tfoo("hi"); // Error