Struct EventLog 

pub struct EventLog<T: Clone> { /* private fields */ }

Generic cursor-based event log with undo/redo and named checkpoints.

Events are appended at the cursor position. The cursor always points one past the last applied event. Undo moves the cursor back; redo moves it forward. Appending a new event truncates the redo tail.

Checkpoint sentinels are stored in the log but skipped during undo/redo traversal.

Implementations

impl<T: Clone> EventLog<T>

pub fn new() -> Self

Creates a new empty EventLog.

pub fn append(&mut self, event: T)

Appends an event, truncating any redo history beyond the cursor.

pub fn checkpoint(&mut self, name: &str)

Creates a named checkpoint at the current cursor position, truncating any redo tail first (same semantics as append).

pub fn undo(&mut self, count: usize) -> Vec<T>

Undoes up to count non-checkpoint events. Returns events in reverse order (most recent first) for the caller to reverse-apply.

pub fn undo_to(&mut self, name: &str) -> Result<Vec<T>, String>

Undoes to a named checkpoint. Returns events in reverse order. Returns Err if the checkpoint doesn’t exist or is at/beyond cursor.

pub fn redo(&mut self, count: usize) -> Vec<T>

Redoes up to count non-checkpoint events. Returns events in forward order for the caller to re-apply.

pub fn recent(&self, count: usize) -> Vec<T>

Returns the last count non-checkpoint events (up to cursor) in chronological order (oldest first). If count is 0, returns all.

pub fn cursor(&self) -> usize

Returns the current cursor position (one past last applied event).

pub fn length(&self) -> usize

Returns the total number of entries in the log (including checkpoints).

pub fn can_undo(&self) -> bool

Returns whether there are events before the cursor that can be undone.

pub fn can_redo(&self) -> bool

Returns whether there are events after the cursor that can be redone.

Trait Implementations

impl<T: Clone> Default for EventLog<T>

fn default() -> Self

Returns the “default value” for a type.