undo in editor<%>

Undoes the last editor change, if undos have been enabled by calling set-max-undo-history with a non-zero integer.

The user may enable Emacs-style undo for editors; see Preferences. Normally, undo operations add to the redo stack (see redo), and any undoable (non-undo) operation clears the redo stack. With Emacs-style undo, the redo stack is added back to the undo stack, along with the original undos, so that a complete history is kept in the undo stack.

The system may perform an undo without calling this method in response to other method calls. Use methods such as on-change to monitor editor content changes.

See also add-undo .

• (send an-editor undo) -> void

  If the editor is currently performing an undo or redo, the method call is ignored.