   repeatPrefix: (e) ->
     keyboardEvent = e.originalEvent?.originalEvent ? e.originalEvent
     num = parseInt(atom.keymaps.keystrokeForKeyboardEvent(keyboardEvent))
-    if @tailOperation()?.isRepeat?()
-      @tailOperation().addDigit(num)
+    if @getTailOperation()?.isRepeat?()
+      @getTailOperation().addDigit(num)
     else
       if num is 0
         e.abortKeyBinding()

  # Returns nothing.
  linewiseAliasedOperator: (constructor) ->
    if @isSameOperatorPending(constructor)
      new Motions.MoveToRelativeLine(@editor, this)
    else
      new constructor(@editor, this)

  # Private: Removes all operations from the stack.
  #
  # Returns nothing.
  clearOperationsQueue: ->
    @operationsQueue = []

  undo: ->
