app-state 0.1

app_state

Minimalistic reactive local application state toolkit.

Installation

pip install app_state

Usage

from app_state import state

state["some_data"] = 42  # Alternatively: state.some_data = 42

State is a dictionary-like object, representing a tree of sub-dictionaries. For covenience, branches can also be accessed with . as attributes.

@on(*patterns) decorator makes the decorated function or method to be called each time when the state subtree changes. Each pattern is a dot-separated string, representing state subtree path.

from app_state import state, on

@on('state.countries')
def countries():
    print(f'countries changed to: {state.countries}')

@on('state.countries.Australia.population')
def au_population():
    population = state.get('countries', {}).get('Australia', {}).get('population')
    print(f'Australia population now: {population}')

state.countries = {'Australia': {'code': 'AU'}, 'Brazil': {}}
state.countries.Australia.population = 4500000

will print:

countries changed to: {'Australia': {'code': 'AU'}, 'Brazil': {}}
Australia population now: None
countries changed to: {'Australia': {'code': 'AU', 'population': 4500000}, 'Brazil': {}}
Australia population now: 4500000

@on() can wrap a method of a class. When state changes, that method will be called for every instance of this class.

from app_state import state, on

class MainWindow:
    @on('state.user')
    def on_user(self):
        self.settext(f'Welcome, {state.user.name}')

mainwindow = MainWindow()

state.user = {'name': 'Alice'}