On Mar 21, 8:47 am, grocery_stocker <cdal...@gmail.com> wrote:
> On Mar 21, 6:38 am, Tim Chase <python.l...@tim.thechases.com> wrote:
>
>
>
> > > For example, this means that there can be a start node supposedly.
> > > Having a value of 0. It is pointing to node 1 with the value of "a"
> > > and to node 2 with the value of "b". Trying to make something like an
> > > NFA. Where id be changing regular expressions to NFAs.
>
> > John has already pointed out the preconception problems of
> > "linked list".
>
> > In the past, I've done NFA with a state machine:
>
> > (STATE_A,
> > STATE_B,
> > STATE_C,
> > STATE_D,
> > ) = range(4)
>
> > transitions = {
> > # values are tuples of (newstate, transition_function)
> > STATE_A: [
> > (STATE_B, lambda x: x > 5),
> > (STATE_C, lambda x: x > 10),
> > (STATE_D, lambda x: x > 100),
> > ],
> > STATE_B: [
> > (STATE_A, lambda x: x < 5),
> > (STATE_C, lambda x: x > 10),
> > ],
> > STATE_C: [
> > (STATE_B, lambda x: x < 10),
> > (STATE_D, lambda x: x > 100),
> > ],
> > STATE_D: [],
> > }
>
> > You may have to carry around extra information regarding your
> > state, and tweak accordingly. Instead of tuples of (newstate,
> > transition_function), you could just use transition functions
> > that return the new state, or None if they're not satisfied.
>
> > You then simply maintain your current state, and then test your
> > incoming stream of tokens/data against your transition function
> > to see if you can transition to the resulting state. Depending
> > on whether you need back-tracking, you'll want to gather all the
> > possible results, or otherwise may just settle for the first
> > available transition to a new state.
>
> And if you don't mind me asking. How do you invoke lambda from
> transitions?
Disregard that. I think I figured it out.
If you had something like...
>>> transitions = {1: [2, lambda x: 2*x]}
You would probably call it like...
>>> transitions[1][1](4)
8
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