Returns True if the parentheses in the input string is balanced

parentheseBalance.hs

parentheseBalance :: String -> Bool
parentheseBalance s = f s 0
    where
    f s c
        | s == [] =     c == 0  -- if string is empty, return true if count == 0
        | c < 0 =       False
        | head s == '(' = f (tail s) (c+1)
        | head s == ')' = f (tail s) (c-1)
        | otherwise     = f (tail s) c
        
-- parentheseBalance ")" == False
-- parentheseBalance "()(" == False
-- parentheseBalance "()" == True