Tempated class instantiation

[Mike L.]

Rory McGuire Wrote:

> Mike L. <sgtmuffles at myrealbox.com> wrote:
>  
> > Simen kjaeraas Wrote:
> > 
> >> On Wed, 16 Dec 2009 07:25:39 +0100, Mike L. <sgtmuffles at myrealbox.com>  
> >> wrote:
> >> 
> >> > I'm making a class template that only works with strings, so I thought  
> >> > it'd be good to instantiate each template with char, wchar, and dchar  
> >> > right in the template's module so that when it's compiled it'll be part  
> >> > of the .obj file and won't have to compile it for every other project  
> >> > that uses it. However, I get an error reproducible with this:
> >> >
> >> > module test;
> >> >
> >> > class A(T)
> >> > {
> >> >  version(broken)
> >> >  {
> >> >   class B
> >> >   {
> >> >    T blah() { return t; }
> >> >   }
> >> >  }
> >> >  
> >> >  T t;
> >> > }
> >> >
> >> > mixin A!(int);
> >> >
> >> > int main()
> >> > {
> >> >  A!(int) a = new A!(int)();
> >> >  return 0;
> >> > }
> >> >
> >> > If what I want to do makes sense, how should I be doing it?
> >> 
> >> It makes sense. Seems to be another compiler bug, but I have
> >> no good overview of which (might even be a new one).
> >> This compiles and runs:
> >> 
> >> class A(T)
> >> {
> >>      version(broken)
> >>      {
> >>          class B
> >>          {
> >>              // Explicitly state which t we're talking about.
> >>              T blah() { return this.outer.t; }
> >>          }
> >>      }
> >> 
> >>      T t;
> >> }
> >> 
> >> mixin A!(int);
> >> 
> >> int main()
> >> {
> >>      A!(int) a = new A!(int)();
> >>      return 0;
> >> }
> >> 
> >> 
> >> -- 
> >> Simen
> > 
> > Thanks for the reply, that seems to be working for my project too, but the 
> code gets really ugly really fast. Should I submit a bug report?
> > 
> > --Mike L.
> > 
> 
> As grauzone said, you have to use an alias, or you could use a template. but the 
> code above just does the same old templated class instantiation, you can leave 
> out the mixin A!(int); line completely.
> As far as I understand it a template is always evaluated at least once for each 
> type T. So perhaps if you used it in the module that declares it the compiler 
> would detect that it doesn't need to compile it again but I'm not convinced of 
> that because the instance is in a different module.
> 
> -Rory
> 

So it sounds like my best bet is to just make a bogus alias. I guess I probably couldn't do something like mixin A!(int) and mixin A!(char), because each would create a class named A and there would be a naming conflict.

--Mike L.