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@firebelley
Created August 27, 2024 21:18
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class_name CallableStateMachine
var state_dictionary = {}
var current_state: String
func add_states(
normal_state_callable: Callable,
enter_state_callable: Callable,
leave_state_callable: Callable
):
state_dictionary[normal_state_callable.get_method()] = {
"normal": normal_state_callable,
"enter": enter_state_callable,
"leave": leave_state_callable
}
func set_initial_state(state_callable: Callable):
var state_name = state_callable.get_method()
if state_dictionary.has(state_name):
_set_state(state_name)
else:
push_warning("No state with name " + state_name)
func update():
if current_state != null:
(state_dictionary[current_state].normal as Callable).call()
func change_state(state_callable: Callable):
var state_name = state_callable.get_method()
if state_dictionary.has(state_name):
_set_state.call_deferred(state_name)
else:
push_warning("No state with name " + state_name)
func _set_state(state_name: String):
if current_state:
var leave_callable = state_dictionary[current_state].leave as Callable
if !leave_callable.is_null():
leave_callable.call()
current_state = state_name
var enter_callable = state_dictionary[current_state].enter as Callable
if !enter_callable.is_null():
enter_callable.call()
@SaintHF
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SaintHF commented Jul 17, 2025

Heya, if you're still working with this I'm running into an issue where the "enter" and "leave" callables are still being called when using await timer randf_range to determine when to transition. Any suggestions? Found the problem, I had another part of the script executing functions that shouldn't have been executed.

@Chum4k3r
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@mbnewsom All your code can be in a single script. I've updated it below, also fixed the typo in the State._init declaration.

I'll probably update this code further once I test it with the new variadic arguments, so we will be allowed to declare this as a single external Node, extend its script to declare the states and give arguments to .update() and .state_change(), allowing transient variables, like delta and controller inputs, being passed into, instead of holding global references, to access these values inside the state functions.

# callable_state_machine.gd
class_name CallableStateMachine


class_name State

    var normal: Callable
    var enter: Callable
    var leave: Callable

    func _init(normal: Callable, enter: Callable, leave: Callable):
        self.normal = normal
        self.enter = enter
        self.leave = leave


var state_dictionary: Dictionary[String, State] = {}
var current_state: String

func add_state(
    normal_state_callable: Callable,
    enter_state_callable: Callable,
    leave_state_callable: Callable
):
    state_dictionary[normal_state_callable.get_method()] = \
        State.new(normal_state_callable, enter_state_callable, leave_state_callable)

func set_initial_state(state_callable: Callable):
    var state_name = state_callable.get_method()
    if state_dictionary.has(state_name):
        _set_state(state_name)
    else:
        push_warning("No state with name " + state_name)


func update():
    if current_state != "":  #null here was a bug. Strings default to "", not null
        state_dictionary[current_state].normal.call()


func change_state(state_callable: Callable):
    var state_name = state_callable.get_method()
    if state_dictionary.has(state_name):
        _set_state.call_deferred(state_name)
    else:
        push_warning("No state with name " + state_name)


func _set_state(state_name: String):
    if current_state:
        var leave_callable = state_dictionary[current_state].leave
        if leave_callable.is_valid():
	    leave_callable.call()
	
    current_state = state_name
    var enter_callable = state_dictionary[current_state].enter
    if enter_callable.is_valid():
        enter_callable.call()

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