Check Instance of Template for Parameter Type/Value

[anonymous via Digitalmars-d-learn]

On Monday, October 19, 2015 04:51 PM, Stewart Moth wrote:

> struct Vector(type, int dimension_){ ... }
> 
> Where type is going to be an int/float/etc and dimension_ is
> 2/3/4.
> 
> I could write a bunch of functions for each case, but I'd rather
> not... I'd like to use something like the following:
> 
> void foo(T)(Array!T array){
>      if(isInstanceOf!(Vector, T)){
>          //get type of T or check it
>          //test if dimension_ is 2 or 3 or 4
>          ...
>      } else {
>          //Non-vector stuff
>          ...
>      }
> }
> 
> But to do that I need to check that parameters of T as if it were
> an instantiated instance of Vector and I'm not sure how to
> accomplish that... Can anyone help me out with what I need to do?

You can use std.traits.TemplateArgsOf:
----
    static if(isInstanceOf!(Vector, T)){ /* note: must be a static if */
        enum dimensions = TemplateArgsOf!T[1];
        static if(dimensions == 2) {...}
    }
----