Struct UndoEntry 

pub struct UndoEntry<C> { /* private fields */ }

One reversible unit — a snapshot of a single document state (TR-010).

Restoring an entry reproduces the document at this state: the CST snapshot, the exact prior buffer bytes (source_text), and the caller’s cursor value (cursor). Generic over the cursor/metadata type C so ronin-core stays decoupled from any surface’s cursor representation (see module docs).

Downstream reuse (E005 / E008 — TR-013)

Downstream editing epics build an entry with new after applying an edit, then hand it to UndoStack::record. On undo/redo they read back the snapshot through source_text (write to the buffer verbatim — exact-prior-byte restore), cst_snapshot (reuse the structurally-shared tree without re-parsing), and cursor (restore caret/selection).

Implementations

impl<C> UndoEntry<C>

pub fn new(cst_snapshot: CstDocument, source_text: String, cursor: C) -> Self

Snapshot a document state into a new undo unit.

cst_snapshot should correspond to source_text (the CST whose printout is those exact bytes); cursor is the surface state to restore alongside.

pub fn cst_snapshot(&self) -> &CstDocument

The CST snapshot at this state.

pub fn source_text(&self) -> &str

The exact prior buffer text this unit restores.

pub fn cursor(&self) -> &C

The cursor/metadata value restored with this state.

pub fn byte_size(&self) -> usize

The retained byte-size this entry contributes to the stack’s size cap — the length of the snapshot’s source_text in bytes (TR-024).

The CST snapshot itself is structurally shared and is not counted here; the source text is the dominant, deterministic per-unit cost.

Trait Implementations

impl<C: Clone> Clone for UndoEntry<C>

fn clone(&self) -> UndoEntry<C>

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl<C: Debug> Debug for UndoEntry<C>

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

Formats the value using the given formatter.