Well, does it mean: (x, y) -> x + y Or: (x) -> x + x If I didn't know the language, I'd assume the latter, so it fails the principle of least surpri

Well, does it mean: (x, y) -> x + y Or: (x) -> x + x If I didn't know the language, I'd assume the latter, so it fails the principle of least surprise (at least for me).