Peter Otten <__pete...@web.de>:
> Why have the function return a name? Why not just another function?
As people have said, there are many ways to skin the cat.
A function can represent a state if it is the only type of event the
state machine must process. A regular expression parser would be an
example.
In the general case, a state machine is a matrix of M states by N types
of event. Then, one natural manner of representing a state is a nested
class:
class Lackey:
def __init__(self):
lackey = self
class Idle:
def handle_ding(self):
lackey.start_timer(10)
lackey.set_state(Dinged)
class Dinged:
def handle_dong(self):
lackey.cancel_timer()
lackey.open_door()
lackey.ask_for_name()
lackey.start_timer(20)
lackey.set_state(AwaitingName)
def handle_timeout(self):
lackey.open_door()
lackey.shoo_visitor_away()
lackey.set_state(Annoyed)
# other state classes here...
self.set_state(Idle)
def set_state(self, state):
log("Lackey(): New state: {}".format(
id(self), state.__class__.__name__))
self.state = state()
def handle_ding(self):
self.state.handle_ding()
def handle_dong(self):
self.state.handle_dong()
def handle_timeout(self):
self.state.handle_timeout()
def start_timer(self):
# etc etc
Marko
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