Re: template template parameter

[Ali Çehreli]

On 03/30/2011 04:32 PM, Caligo wrote:
> I have a struct that looks something like this:
>
> struct Box(T, size_t width, size_t height){
>
> alias width width_;
> alias height height_;
>
> //do something with a Box of different size
>    void Fun( B )(B b){
>      // using width and height of b
>      B.width_;
>      B.height_;
>    }
> }
>
> auto b1 = Box!(double, 2, 7)();
> auto b2 = Box!(double, 3, 4)();
> b1.Fun(b2);
>
> I think the technical name for this is template template parameter.
> Using the above I'm able to do what I need to do, but is there a
> better way?
> and should I use alias or enum?
You later also said:

> how do I access the parameters of a template parameter

With the help of function template parameter deduction, I was able to do 
it by spelling out the parameters of Fun:

import std.stdio;

struct Box(T, int width, int height)
{
    void Fun(T2, int width2, int height2)(Box!(T2, width2, height2) b)
    {
        writeln(width2, ' ', height2);
    }
}

void main()
{
    auto b1 = Box!(double, 2, 7)();
    auto b2 = Box!(double, 3, 4)();
    b1.Fun(b2);
}

Ali