def pop_int(count = 1)
      i = stack.pop(count).map{ |s| cast_to_int(s) }
      count == 1 ? i.first : i
    end
def pop_int(count = 1)
      i = stack.pop(count).map{ |s| cast_to_int(s) }
      count == 1 ? i.first : i
    end
pop the item with the int value for the number specified by +count+ from the stack.