What is the Pythonic way to implement a simple FSM?

Question

Yesterday I had to parse a very simple binary data file - the rule is, look for two bytes in a row that are both 0xAA, then the next byte will be a length byte, then skip 9 byte

Answer 1

I am a little apprehensive about telling anyone what's Pythonic, but here goes. First, keep in mind that in python functions are just objects. Transitions can be defined with a dictionary that has the (input, current_state) as the key and the tuple (next_state, action) as the value. Action is just a function that does whatever is necessary to transition from the current state to the next state.

There's a nice looking example of doing this at http://code.activestate.com/recipes/146262-finite-state-machine-fsm. I haven't used it, but from a quick read it seems like it covers everything.

A similar question was asked/answered here a couple of months ago: Python state-machine design. You might find looking at those responses useful as well.