Query valid inputs?

[jackgeek]

Hi there. I'm new to automa and interested in your library. Thank you for the effort you have put in and for making it open source.

Can you recommend an approach for knowing which inputs are valid at any given time? It seems to me that the FSM has this information and so I should be able to query it. Is there a way I can know what inputs are presently valid/subscribe to changes?

My use case right now is a simple calculator app. I want to bind the input buttons to inputs and auto disable them if the input is not valid in the current state.

How would you approach this?

Thank you for your time and consideration.

[jackgeek]

Here is the hacky work around that I have come up with... But there must be a better way?

from automat._core import Transitioner

def get_transitioner(fsm):
    attributes = fsm.__dict__
    for attribute in attributes.values():
        if isinstance(attribute, Transitioner):
            return attribute

def print_valid_inputs(fsm):
    transitioner = get_transitioner(fsm)
    automaton = transitioner.__dict__["_automaton"]
    current_state = transitioner.__dict__["_state"]
    transitions = automaton.__dict__["_transitions"]

    def for_current_state(t):
        return t[0] == current_state

    for t in filter(for_current_state, transitions):
        f = t[1].method.__name__
        print(f)

[jackgeek]

Interestingly, the above hack only works after the first input has been executed. Beforehand the _automaton attribute is not in the transitioner dict

[glyph]

It would be great to have a patch to support this.

[glyph]

I don’t have much time to look into this myself, but have you used the visualizer? It’s the closest thing to an inspection API we have yet.