Struct DocumentHistory 

pub struct DocumentHistory { /* private fields */ }

Undo/redo history for a document.

Changes are pushed as they are applied — prefer push_applied with the result of DocumentChange::try_apply, so the recorded undo evidence is derived from the document rather than caller-authored. undo returns the inverse of the most-recent change; redo re-applies a change that was undone.

Implementations

impl DocumentHistory

pub fn new() -> Self

Creates an empty history.

pub fn push_applied(&mut self, applied: &AppliedChange)

Records a verified change. Any future (redo) stack is cleared.

The forward change is reconstructed from the applied change’s derived inverse, so both undo and redo evidence come from the document itself.

pub fn push(&mut self, change: DocumentChange)

Records a new change. Any future (redo) stack is cleared.

The change’s old_text is trusted as-is; prefer push_applied, which records evidence derived from the document.

pub fn undo(&mut self) -> Option<&DocumentChange>

Removes the most-recent change from the undo stack and returns a reference to it, or None if the stack is empty.

The inverse of the returned change is placed on the redo stack.

pub fn redo(&mut self) -> Option<&DocumentChange>

Re-applies the most-recently-undone change and returns a reference to it, or None if the redo stack is empty.

pub fn can_undo(&self) -> bool

Returns true if there is at least one change to undo.

pub fn can_redo(&self) -> bool

Returns true if there is at least one change to redo.

Trait Implementations

impl Debug for DocumentHistory

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

Formats the value using the given formatter.

impl Default for DocumentHistory

fn default() -> DocumentHistory

Returns the “default value” for a type.