DefineTemplateVars

import std.string;

static struct X(Args...)
{
    void func( Args args )
    {
        static if( Args.length == 1 && is( Args[0] == string ) )
            assert( args[0] == "hello" );
        else static if( Args.length == 2 && is( Args[0] == float ) && is( Args[1] == int ) )
        {
            import std.math;
            assert( abs(args[0] - 3.14) < float.epsilon );
            assert( args[1] == 12 );
        }
        else static assert(0,"undefined for this unittest");
    }
}

static class ZZ
{
    mixin DefineTemplateVars!( X, TemplateVarDef!("ok",string),
                                  TemplateVarDef!("da",float,int),
            );
}

auto zz = new ZZ;
static assert( is( typeof(zz.ok) == X!string ) );
static assert( is( typeof(zz.da) == X!(float,int) ) );
zz.ok.func( "hello" );
zz.da.func( 3.14, 12 );

enum mark;

static class A
{
    void s1() @mark {}
    void f2() {}
    @mark
    {
        void s3( int, string ) {}
        void s4( float x ) {}
    }
}

template isVoidMarked(T)
{
    alias isVoidMarked = isVoidMarkedFunc;

    template isVoidMarkedFunc(string n)
    {
        static if( __traits(compiles,impl!(__traits(getMember,T,n))) )
            enum isVoidMarkedFunc = impl!(__traits(getMember,T,n));
        else enum isVoidMarkedFunc = false;

        template impl(alias f)
        {
            enum impl = isCallable!f &&
                        is( ReturnType!f == void ) &&
                        hasAttrib!(mark,f);
        }
    }
}

template TemplateVarDefFromMethod(T)
{
    template TemplateVarDefFromMethod(string name)
    {
        alias TemplateVarDefFromMethod = TemplateVarDef!(name,ParameterTypeTuple!(__traits(getMember,T,name)));
    }
}

alias tvd = staticMap!( TemplateVarDefFromMethod!A, staticFilter!(isVoidMarked!A,__traits(allMembers,A)) );
static assert( tvd.length == 3 );
alias exp = TypeTuple!( TemplateVarDef!("s1"), TemplateVarDef!("s3",int,string), TemplateVarDef!("s4",float) );
static assert( is(tvd[0] == exp[0]) );
static assert( is(tvd[1] == exp[1]) );
static assert( is(tvd[2] == exp[2]) );