Another attempt at passing keyword-arguments to functions

[Tomer Filiba via Digitalmars-d]

What do you guys think?

struct KW(alias F) {
    private import std.string, std.range, std.traits, 
std.typecons, std.algorithm;
    mixin({
        string s;
        foreach(i, name; ParameterIdentifierTuple!F) {
            static assert ((ParameterStorageClassTuple!F[i] & 
ParameterStorageClass.out_) == 0, "Cannot pass 'out' parameters");
            static assert ((ParameterStorageClassTuple!F[i] & 
ParameterStorageClass.ref_) == 0, "Cannot pass 'ref' parameters");
            s ~= fullyQualifiedName!(ParameterTypeTuple!F[i]) ~ " 
" ~ name ~ ";\n";
        }
        return s;
    }());
    private static KW _instance;
    @disable this();
    @disable this(this);

    static auto opIndex(T...)(ref T _) {
        static assert (T.length == 
ParameterIdentifierTuple!F.length);
        mixin("return F(" ~ 
ParameterIdentifierTuple!F.tuple.array.map!(p => "_instance." ~ 
p).join(",") ~ ");");
    }

    static KW* opDollar(int dim)() {
        return &_instance;
    }
}

auto f(int x, string y) {
    return x*2 + y.length;
}

void main() {
    auto res = KW!f[$.y = "foo", $.x = 5];

    import std.stdio;
    writeln(res);     // 13
}


-tomer