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#
# trafficlightstate.pystate
#
# state machine model of the states and associated behaviors and properties for each
# different state of a traffic light
# define state machine with transitions
# (states will be implemented as Python classes, so use name case appropriate for class names)
statemachine TrafficLightState:
Red -> Green
Green -> Yellow
Yellow -> Red
# statemachine only defines the state->state transitions - actual behavior and properties
# must be added separately
# define some class level constants
Red.cars_can_go = False
Yellow.cars_can_go = True
Green.cars_can_go = True
# setup some class level methods
def flash_crosswalk(s):
def flash():
print("%s...%s...%s" % (s, s, s))
return flash
Red.crossing_signal = staticmethod(flash_crosswalk("WALK"))
Yellow.crossing_signal = staticmethod(flash_crosswalk("DONT WALK"))
Green.crossing_signal = staticmethod(flash_crosswalk("DONT WALK"))
# setup some instance methods
def wait(nSeconds):
def waitFn(self):
print("<wait %d seconds>" % nSeconds)
return waitFn
Red.delay = wait(20)
Yellow.delay = wait(3)
Green.delay = wait(15)
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