"""

 S -> E
 E -> 1 | "(" E ")"


         S
         |
         E
       /   \
      1    ( E  )
            / \
           1  ( E )

 Top-down = LL e.g. recursive descent




"""

def start(symbols):
    return expression(symbols)

def expression(symbols):
    print(" expression {} ? ".format(symbols))
    if symbols == "1":
        return True
    elif symbols[0] == '(' and symbols[-1] == ')':
        return expression(symbols[1:-1])
    else:
        return False

result = start("((1))")
print(result)