Statomata is a strictly typed, flexible library for building and running finite state machines (FSMs) and automata in Python. It provides core automata implementations out of the box and lets you define custom states and state management logic.
- 🧠 State Interface & Context: Follow the state machine OOP pattern with clear, isolated state definitions.
- ⚡ Built-in Automata: feel free to use one of the predefined automata classes from SDK (sync / async; unary / iterable)
- 🏗 Custom Automata Support: Build your own automata with custom state management logic. You can choose declarative style or built custom automata using provided interfaces.
- ✅ Strict Typing: Designed for type safety and clarity with full type hints.
pip install statomataUse high-level declarative style:
from statomata.declarative import DeclarativeStateMachine, State
class OpenCloseExample(DeclarativeStateMachine):
closed = State(initial=True)
opened = State()
@closed.to(opened)
def open(self) -> str:
return "Opened"
@opened.to(closed)
def close(self) -> str:
return "Closed"Run the state machine:
from contextlib import suppress
from statomata.exception import InvalidStateError
sm = OpenCloseExample()
print(sm.open()) # Output: Opened
print(sm.close()) # Output: Closed
with suppress(InvalidStateError):
sm.close()Or you can use low-level style:
from statomata.abc import State, Context
from statomata.exception import InvalidStateError
class OpenState(State[str, str]):
def handle(self, income: str, context: Context[State[str, str]]) -> str:
if income != "close":
raise InvalidStateError(self, message="already opened")
context.set_state(ClosedState())
return "Closed"
class ClosedState(State[str, str]):
def handle(self, income: str, context: Context[State[str, str]]) -> str:
if income != "open":
raise InvalidStateError(self, message="already closed")
context.set_state(OpenState())
return "Opened"Run the state machine:
from contextlib import suppress
from statomata.exception import InvalidStateError
from statomata.sdk import create_unary_sm
sm = create_unary_sm(ClosedState())
print(sm.run("open")) # Output: Opened
print(sm.run("close")) # Output: Closed
with suppress(InvalidStateError):
sm.run("close")