def urbanmain() = {
  import C3a._

  assert(compute(syard(split("3 + 4 * ( 2 - 1 )"))) == 7)
  assert(compute(syard(split("10 + 12 * 33"))) == 406)
  assert(compute(syard(split("( 5 + 7 ) * 2"))) == 24)
  assert(compute(syard(split("5 + 7 / 2"))) == 8)
  assert(compute(syard(split("5 * 7 / 2"))) == 17)
  assert(compute(syard(split("9 + 24 / ( 7 - 3 )"))) == 15)
}