/** Tuple unpacker

 *

 * Usage: myTuple.unpack!((x, y) => f(x, y));

 *

 * Arguments are bound by order; names are irrelevant.

 *

 * Based on 'tupArg' by Dukc:

 *   https://forum.dlang.org/thread/rkfezigmrvuzkztxqqxy@forum.dlang.org

 */

template unpack(alias func)

{

    import std.typecons: isTuple;

​

    auto unpack(TupleType)(TupleType tup)

        if (isTuple!TupleType)

    {

        return func(tup.expand);

    }

}

​

​

auto scaleAll(int[] xs, int m) @nogc {

    import std.range: repeat, zip;

    import std.algorithm: map;

    return repeat(m).zip(xs).map!(unpack!((m, x) => m * x));

}

​

void main()

{

    import std.algorithm: each;

    import std.stdio: writeln;

    [1, 2, 3, 4, 5].scaleAll(6).each!writeln;

}