forstate

The forstate module introduces the for_state method decorator, designed to facilitate state-specific method dispatching.

This decorator enables the definition of multiple versions of the same method, which are dynamically called based on the object's internal state, as indicated by its _state attribute.

Installation

You can easily install the forstate module via pip. Simply run the following command in your terminal:

pip install forstate

Usage

• Import the for_state decorator and, if needed, the ANY_STATE marker.

• Decorate your class methods with @for_state, specifying the relevant state names for each method. This enables you to define distinct behaviors for the same method name based on the object's current state.

  For instance:

  @for_state("state1")
  def foo(self, arg):
      # Implementation for state1
      pass
  
  @for_state("state2", "state3")
  def foo(self, arg):
      # Implementation for state2 and state3
      pass
  

• Utilize the ANY_STATE marker to designate fallback methods that will be invoked when no specific version of a method is defined for the current state.

Example

from forstate import for_state, ANY_STATE

class MyStatefulObject:
    def __init__(self):
        self._state = "state0"  # Initial state

    @for_state("state1")
    def action(self):
        print("Action for state 1")

    @for_state("state2", "state3")
    def action(self):
        print("Action for state 2")

    @for_state(ANY_STATE)
    def action(self):
        print("Action for any state")

obj = MyStatefulObject()

obj._state = "state1"
obj.action()  # Output: Action for state 1

obj._state = "state2"
obj.action()  # Output: Action for state 2

obj._state = "unknown"
obj.action()  # Output: Action for any state

Copyright and License

Copyright (c) 2025 Salvador Fandiño (sfandino@yahoo.com)

This project is licensed under the MIT License. See the LICENSE file for more details.