Re: creating a variadic interface

[JS]

On Monday, 8 July 2013 at 10:16:22 UTC, John Colvin wrote:
On Monday, 8 July 2013 at 09:34:46 UTC, JS wrote:

this may seem a bit nonsensical but it is just an example:

interface A(T, S...)
{
  ... Generate a getter for each type in S...
  // e.g., @property S[0] property1();
  //       @property S[1] property2();
  // ....
}

I imagine I have to use a mixin template but I'm unsure how to 
create a static loop that can be used properly.

I think maybe using mixin's of mixin's is possible but I can't 
think of any simple way. Any ideas?

Here you go :)

//just to hide the string mixin.
mixin template Getters(S ...)
{
        mixin(GettersImpl!S);
}

import std.conv : to;
template GettersImpl(S ...)
{
        static if(S.length == 0)
        {
                enum GettersImpl = "";
        }
        else static if(S.length == 1)
        {
		enum GettersImpl = "@property " ~ (S[$-1]).stringof ~ " 
property" ~ to!string(S.length) ~ "();\n";
        }
        else
        {
		enum GettersImpl = "@property " ~ (S[$-1]).stringof ~ " 
property" ~ to!string(S.length) ~ "();\n"
                                                   ~ GettersImpl!(S[0..$-1]);
        }
}


interface A(S...)
{
        mixin Getters!S;
}

class B : A!(int, long, string)
{
        //if everything works, we get errors here for missing methods.
}



I guess you beat me too it but I came up with something very 
similar which I think works too(uses foreach instead of 
recursion)..


mixin template a(T...)
{
        template b(TT...)
        {
                static string eval()
                {
                        string s;
                        int i = 0;
                        foreach(t; TT)
                                s = "@property "~(t).stringof~" 
Name"~to!string(i++)~"();\n";
                        return s;
                }
                enum b = eval();
        }

        mixin("mixin(b!T);");
        
}