struct UndoStack

Swift

struct UndoStack

Undo/redo history for a single buffer.

Coalescing is deliberately time-free. A timer makes the split points depend on how fast someone types, which is both untestable and surprising ("why did that undo only half a word?"). Instead a run breaks on a word boundary, a direction change, or anything that is not a simple continuation — deterministic, and it matches where a user thinks a word ended.

Sources/LavaText/TextEdit.swift:68

Constructors

init()

Creates an empty history.

Sources/LavaText/TextEdit.swift:73

Properties

var canRedo: Bool { get }

Whether there is an undone edit to redo.

Sources/LavaText/TextEdit.swift:78

var canUndo: Bool { get }

Whether there is an edit to undo.

Sources/LavaText/TextEdit.swift:76

Methods

mutating func clear()

Forgets all history.

Sources/LavaText/TextEdit.swift:111

mutating func popRedo() -> TextEdit?

Takes the most recently undone edit and moves it back to undo. Returns it to be applied again.

Sources/LavaText/TextEdit.swift:104

mutating func popUndo() -> TextEdit?

Takes the most recent edit off the undo history and moves it to redo. Returns it, still in its forward form: apply its inverted to undo it.

Sources/LavaText/TextEdit.swift:96

mutating func record(_ edit: TextEdit)

Records a new edit, merging it into the previous one when the two read as one action (typing on through a word, say). Clears the redo history.

Sources/LavaText/TextEdit.swift:82