Enum UndoStatus 

pub enum UndoStatus {
    Undone,
    Superseded,
    Empty,
}

What UndoRedoManager::undo_if_head actually did.

The reason this exists: a “take that back” affordance offered for one operation — the Undo button on a toast — cannot use plain undo(), which pops whatever is on top. Anything pushed in the meantime (an autosave, a second window, a background job) silently becomes the thing that gets undone instead. Naming the operation and being told it is no longer the head is the difference between a correct affordance and a data-loss bug.

Variants

Undone

The named command was on top, and has been undone.

Superseded

Something else has been pushed since; nothing was undone.

Empty

The stack is empty; nothing was undone.

Trait Implementations

impl Clone for UndoStatus

fn clone(&self) -> UndoStatus

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for UndoStatus

impl Debug for UndoStatus

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

Formats the value using the given formatter.

impl Eq for UndoStatus

impl Hash for UndoStatus

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for UndoStatus

fn eq(&self, other: &UndoStatus) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for UndoStatus