sub as-left(&f) { sub infix:<@>(|xs) is assoc<left> { &f(|xs); } &infix:<@>; } sub as-right(&f) { sub infix:<@>(|xs) is assoc<right> { &f(|xs); } &infix:<@>; } say (|("a" .. "f"), "Unit").reduce(as-right({"Tuple $^a ($^b)"}));