That's what the Nim compiler does. Bigger than 3 words, pass-by-ref, otherwise pass-by-value. So the only important modifier is whether the parameter is mutab

That's what the Nim compiler does. Bigger than 3 words, pass-by-ref, otherwise pass-by-value. So the only important modifier is whether the parameter is mutable or not. Obviously if mutable it's always passed-by-reference.