Struct StateMachine

pub struct StateMachine<S> { /* private fields */ }

Wrapper to safely replace states of state machine which don’t consume their states. Use this wrapper if state transitions are performed on mutable references rather than consumed states. Example:

fn on_event(event: Event, statemachine: &mut StateMachine<Foo>) {
    statemachine.replace_state(|state| match state {
        State::A(_) => match event {
            Event::A => State::B,
            _ => state,
        }
        State::B => {
            warn!("cannot receive events in State::B");
            state
        }
    })
}

Implementations

impl<S> StateMachine<S>

pub fn new(state: S) -> Self

Constructs a new StateMachine.

pub fn replace_state<F>(&mut self, map: F) -> &mut Self

where F: FnOnce(S) -> S,

Replaces the current state with one lazily constructed by map.

pub fn try_replace_state<F, E>(&mut self, map: F) -> Result<&mut Self, E>

where F: FnOnce(S) -> Result<S, E>, S: Debug,

Replaces the current state with one lazily constructed by map.

pub fn replace_state_with(&mut self, new_state: S) -> &mut Self

Replaces the current state with new_state.

pub fn into_state(self) -> S

Consumes the state machine and returns its current state.

Trait Implementations

impl<S> AsMut<S> for StateMachine<S>

fn as_mut(&mut self) -> &mut S

Converts this type into a mutable reference of the (usually inferred) input type.

impl<S> AsRef<S> for StateMachine<S>

fn as_ref(&self) -> &S

Converts this type into a shared reference of the (usually inferred) input type.

impl<S: Debug> Debug for StateMachine<S>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<S> Deref for StateMachine<S>

type Target = S

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<S> DerefMut for StateMachine<S>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.

impl<S: PartialEq> PartialEq for StateMachine<S>

fn eq(&self, other: &Self) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.