import std.typetuple;
import std.typecons;

struct Foo
{
    void test(int x, double y) { }

    void opOpAssign(string op, T...)(T t)
        if (op == "~")
    {
        test(t);
    }
}

void main()
{
    Foo foo;
    foo.opOpAssign!"~"(4, 5.0);  // ok
    foo ~= tuple(4, 5.0);  // fail
}

If I understand this correctly in the first call T becomes a D language tuple, while in the second one it's a phobos library tuple. I really hate this distinction and would love these two to be merged so the second call could compile.

Is it possible to expand the phobos tuple in the call to test()? I can use the isTuple template in a `static if` to figure out if it needs expansion, so all that's left is to actually expand the phobos tuple.

"Andrej Mitrovic" <andrej.mitrovich@gmail.com> wrote in message news:mailman.142.1316903007.26225.digitalmars-d-learn@puremagic.com...
>
> Is it possible to expand the phobos tuple in the call to test()? I can use the isTuple template in a `static if` to figure out if it needs expansion, so all that's left is to actually expand the phobos tuple.

Yes, use the Tuple's .expand property.

Andrej Mitrovic wrote:

> import std.typetuple;
> import std.typecons;
> 
> struct Foo
> {
>     void test(int x, double y) { }
> 
>     void opOpAssign(string op, T...)(T t)
>         if (op == "~")
>     {
>         test(t);
>     }
> }
> 
> void main()
> {
>     Foo foo;
>     foo.opOpAssign!"~"(4, 5.0);  // ok
>     foo ~= tuple(4, 5.0);  // fail
> }
> 
> If I understand this correctly in the first call T becomes a D language tuple, while in the second one it's a phobos library tuple. I really hate this distinction and would love these two to be merged so the second call could compile.

.expand on Tuple and generally .tupleof does the trick. Language tuples are quite different and more general than typecons Tuple. If tuples would automatically expand, this would not be possible:

import std.typetuple;
import std.typecons;
import std.stdio;

struct Foo
{
    void test(Tuple!(int, int), double y) { writeln("overload a"); }
    void test(int, int, double y) { writeln("overload b"); }

    void opOpAssign(string op, T...)(T t)
        if (op == "~")
    {
        test(t);
    }
}

void main()
{
    Foo foo;
    foo.opOpAssign!"~"(tuple(4, 2), 5.0);// overload a
    foo.opOpAssign!"~"(tuple(4, 2).tupleof, 5.0);// overload b
}