scamper/actor

OTP actor wrapper for scamper FSMs.

Provides a thin wrapper around gleam/otp/actor to run a state machine as an OTP-compatible process. Events are serialized (processed one at a time) and the pure FSM logic remains fully testable without OTP.

Types

Message

opaque </>

Messages the FSM actor can receive.

pub opaque type Message(state, context, event)

Values

get_context

</>

pub fn get_context(
  subject: process.Subject(Message(state, context, event)),
  timeout timeout: Int,
) -> context

Query the current context of the FSM actor.

get_machine

</>

pub fn get_machine(
  subject: process.Subject(Message(state, context, event)),
  timeout timeout: Int,
) -> scamper.Machine(state, context, event)

Get the full machine from the actor.

get_state

</>

pub fn get_state(
  subject: process.Subject(Message(state, context, event)),
  timeout timeout: Int,
) -> state

Query the current state of the FSM actor.

send_event

</>

pub fn send_event(
  subject: process.Subject(Message(state, context, event)),
  event: event,
  timeout timeout: Int,
) -> Result(
  scamper.Machine(state, context, event),
  error.TransitionError(state, event),
)

Send an event to the FSM actor and wait for the result. Times out after timeout milliseconds.

start

</>

pub fn start(
  config: config.Config(state, context, event),
  initial_state: state,
  context: context,
) -> Result(
  actor.Started(process.Subject(Message(state, context, event))),
  actor.StartError,
)

Start an FSM actor process. Returns the actor’s subject for sending messages.