D'Arcy J.M. Cain, 04.09.2010 20:30:
On Sat, 04 Sep 2010 13:58:00 -0400
Roy Smith<r...@panix.com> wrote:
while True:
state = state(data)
This is the pattern I've always used. Simple and effective for any
state machine which is small enough to code by hand. I generally have
my state methods return (next_state, output) tuples, but that's a detail.
What is "output" for? Is it a string or something else? What do you
do with it? Notice that I create a dictionary which is passed around
so that states can pass whatever information back that they deem useful
and any state can pick up whatever info it needs. for example, in my
sample code every state uses the counter but only two states use the
flag element.
I guess the idea is that each of the states can't arbitrarily modify the
global status (dict) but is restricted to designating a next state and
returning something. So you don't take the risk of introducing side effects
somewhere because all state implementations are pure functions (at least as
far as the state machine itself is concerned).
Stefan
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