Enum Cmd 

pub enum Cmd<M> {
    None,
    Quit,
    Batch(Vec<Cmd<M>>),
    Sequence(Vec<Cmd<M>>),
    Msg(M),
    Tick(Duration),
    Log(String),
    Task(TaskSpec, Box<dyn FnOnce() -> M + Send>),
    SaveState,
    RestoreState,
    SetMouseCapture(bool),
}

Commands represent side effects to be executed by the runtime.

Commands are returned from init() and update() to trigger actions like quitting, sending messages, or scheduling ticks.

Variants

None

No operation.

Quit

Quit the application.

Batch(Vec<Cmd<M>>)

Execute multiple commands as a batch (currently sequential).

Sequence(Vec<Cmd<M>>)

Execute commands sequentially.

Msg(M)

Send a message to the model.

Tick(Duration)

Schedule a tick after a duration.

Log(String)

Write a log message to the terminal output.

This writes to the scrollback region in inline mode, or is ignored/handled appropriately in alternate screen mode. Safe to use with the One-Writer Rule.

Task(TaskSpec, Box<dyn FnOnce() -> M + Send>)

Execute a blocking operation on a background thread.

When effect queue scheduling is enabled, tasks are enqueued and executed in Smith-rule order on a dedicated worker thread. Otherwise the closure runs on a spawned thread immediately. The return value is sent back as a message to the model.

SaveState

Save widget state to the persistence registry.

Triggers a flush of the state registry to the storage backend. No-op if persistence is not configured.

RestoreState

Restore widget state from the persistence registry.

Triggers a load from the storage backend and updates the cache. No-op if persistence is not configured. Returns a message via callback if state was successfully restored.

SetMouseCapture(bool)

Toggle mouse capture at runtime.

Instructs the terminal session to enable or disable mouse event capture. No-op in test simulators.

Implementations

impl<M> Cmd<M>

pub fn none() -> Self

Create a no-op command.

pub fn quit() -> Self

Create a quit command.

pub fn msg(m: M) -> Self

Create a message command.

pub fn log(msg: impl Into<String>) -> Self

Create a log command.

The message will be sanitized and written to the terminal log (scrollback). A newline is appended if not present.

pub fn batch(cmds: Vec<Self>) -> Self

Create a batch of commands.

pub fn sequence(cmds: Vec<Self>) -> Self

Create a sequence of commands.

pub fn type_name(&self) -> &'static str

Return a stable name for telemetry and tracing.

pub fn tick(duration: Duration) -> Self

Create a tick command.

pub fn task<F>(f: F) -> Self

where F: FnOnce() -> M + Send + 'static,

Create a background task command.

The closure runs on a spawned thread (or the effect queue worker when scheduling is enabled). When it completes, the returned message is sent back to the model’s update().

pub fn task_with_spec<F>(spec: TaskSpec, f: F) -> Self

where F: FnOnce() -> M + Send + 'static,

Create a background task command with explicit scheduling metadata.

pub fn task_weighted<F>(weight: f64, estimate_ms: f64, f: F) -> Self

where F: FnOnce() -> M + Send + 'static,

Create a background task command with explicit weight and estimate.

pub fn task_named<F>(name: impl Into<String>, f: F) -> Self

where F: FnOnce() -> M + Send + 'static,

Create a named background task command.

pub fn save_state() -> Self

Create a save state command.

Triggers a flush of the state registry to the storage backend. No-op if persistence is not configured.

pub fn restore_state() -> Self

Create a restore state command.

Triggers a load from the storage backend. No-op if persistence is not configured.

pub fn set_mouse_capture(enabled: bool) -> Self

Create a mouse capture toggle command.

Instructs the runtime to enable or disable mouse event capture on the underlying terminal session.

pub fn count(&self) -> usize

Count the number of atomic commands in this command.

Returns 0 for None, 1 for atomic commands, and recursively counts for Batch/Sequence.

Trait Implementations

impl<M: Debug> Debug for Cmd<M>

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

Formats the value using the given formatter.

impl<M> Default for Cmd<M>

fn default() -> Cmd<M>

Returns the “default value” for a type.