> function f(a, b, c, d) a = a or 1 b = b or 2 c = c or 3 d = d or 4 end Compare with: f = (a=1, b=2, c=3, d=4) -

> function f(a, b, c, d) a = a or 1 b = b or 2 c = c or 3 d = d or 4 end Compare with: f = (a=1, b=2, c=3, d=4) -> ... Also note the latter is correct when you call it as f(false).