In my mind, this usage of parenthesis is less ambiguous. Parenthesis are used in C-like languages for both function calls and order of operations. That is to sa

In my mind, this usage of parenthesis is less ambiguous. Parenthesis are used in C-like languages for both function calls and order of operations. That is to say, they are used in these two ways: foo(a, b, c) // functions (a + b) * c // order of operations Making parenthesis optional for function calls means parenthesis are used instead for just controlling order of operations. In practice, CoffeeScript can't always guess when something is a function call (such as a function call without arguments), so you end up mixing in some function call usage no matter what.