Enum Control

#[non_exhaustive]
pub enum Control<Message> {
    Continue,
    Unchanged,
    Changed,
    Message(Message),
    Quit,
}

Result enum for event handling.

The result of an event is processed immediately after the function returns, before polling new events. This way an action can trigger another action which triggers the repaint without other events intervening.

If you ever need to return more than one result from event-handling, you can hand it to AppContext/RenderContext::queue(). Events in the queue are processed in order, and the return value of the event-handler comes last. If an error is returned, everything send to the queue will be executed nonetheless.

See

• flow!
• try_flow!
• ConsumedEvent

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Continue

Continue with event-handling. In the event-loop this waits for the next event.

Unchanged

Break event-handling without repaint. In the event-loop this waits for the next event.

Changed

Break event-handling and repaints/renders the application. In the event-loop this calls render.

Message(Message)

Handle an application defined event. This calls message to distribute the message throughout the application.

This helps with interactions between parts of the application.

Quit

Quit the application.

Trait Implementations

impl<Message: Clone> Clone for Control<Message>

fn clone(&self) -> Control<Message>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<Message> ConsumedEvent for Control<Message>

fn is_consumed(&self) -> bool

Is this the ‘consumed’ result.

fn or_else<F>(self, f: F) -> Self

where F: FnOnce() -> Self, Self: Sized,

Or-Else chaining with is_consumed() as the split.

fn or_else_try<F, E>(self, f: F) -> Result<Self, E>

where Self: Sized, F: FnOnce() -> Result<Self, E>,

Or-Else chaining with is_consumed() as the split.

fn and<F>(self, f: F) -> Self

where Self: Sized + Ord, F: FnOnce() -> Self,

Then-chaining. Returns max(self, f()).

fn and_try<F, E>(self, f: F) -> Result<Self, E>

where Self: Sized + Ord, F: FnOnce() -> Result<Self, E>,

Then-chaining. Returns max(self, f()).

impl<Message: Debug> Debug for Control<Message>

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

Formats the value using the given formatter.

impl<Message, T: Into<Outcome>> From<T> for Control<Message>

fn from(value: T) -> Self

Converts to this type from the input type.

impl<Message> Ord for Control<Message>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<Message> PartialEq for Control<Message>

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.

impl<Message> PartialOrd for Control<Message>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<Message: Copy> Copy for Control<Message>

impl<Message> Eq for Control<Message>