give_me_a_switch.py

def give_me_a_switch(args):
  sense = False
  for a in args:
    switch a:
      case '+':
        sense = True
      case '-':
        sense = False
      case 'a':
        a.x = sense
      case 'b':
        b = Foo(sense)
  lots_of_code(a, b, ...)