Trait UndoableCmd 

pub trait UndoableCmd: Send + Sync {
    // Required methods
    fn execute(&mut self) -> CommandResult;
    fn undo(&mut self) -> CommandResult;
    fn description(&self) -> &str;
    fn size_bytes(&self) -> usize;
    fn metadata(&self) -> &CommandMetadata;
    fn as_any(&self) -> &dyn Any;
    fn as_any_mut(&mut self) -> &mut dyn Any;

    // Provided methods
    fn redo(&mut self) -> CommandResult { ... }
    fn can_merge(&self, _other: &dyn UndoableCmd, _config: &MergeConfig) -> bool { ... }
    fn merge_text(&self) -> Option<&str> { ... }
    fn accept_merge(&mut self, _other: &dyn UndoableCmd) -> bool { ... }
    fn target(&self) -> Option<WidgetId> { ... }
    fn debug_name(&self) -> &'static str { ... }
}

A reversible command that can be undone and redone.

Commands capture all state needed to execute, undo, and redo an operation. They support merging for batching related operations (like consecutive typing).

Required Methods

fn execute(&mut self) -> CommandResult

Execute the command, applying its effect.

fn undo(&mut self) -> CommandResult

Undo the command, reverting its effect.

fn description(&self) -> &str

Human-readable description for UI display.

fn size_bytes(&self) -> usize

Size of this command in bytes for memory budgeting.

fn metadata(&self) -> &CommandMetadata

Get the command metadata.

fn as_any(&self) -> &dyn Any

Downcast to concrete type for merging.

fn as_any_mut(&mut self) -> &mut dyn Any

Downcast to mutable concrete type for merging.

Provided Methods

fn redo(&mut self) -> CommandResult

Redo the command after it was undone.

fn can_merge(&self, _other: &dyn UndoableCmd, _config: &MergeConfig) -> bool

Check if this command can merge with another.

fn merge_text(&self) -> Option<&str>

Merge another command into this one.

Returns the text to append if merging is possible. The default implementation returns None (no merge).

fn accept_merge(&mut self, _other: &dyn UndoableCmd) -> bool

Accept a merge from another command.

The full command reference is passed to allow implementations to extract position or other context needed for correct merge behavior.

fn target(&self) -> Option<WidgetId>

Get the target widget ID, if any.

fn debug_name(&self) -> &'static str

Debug description of the command.

Trait Implementations

impl Debug for dyn UndoableCmd

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

Formats the value using the given formatter.

Implementors

impl UndoableCmd for CommandBatch

impl UndoableCmd for TextDeleteCmd

impl UndoableCmd for TextInsertCmd

impl UndoableCmd for TextReplaceCmd