lisp/calc/calc-undo.el

   1 ;;; calc-undo.el --- undo functions for Calc
   2
   3 ;; Copyright (C) 1990-1993, 2001-2012 Free Software Foundation, Inc.
   4
   5 ;; Author: David Gillespie <daveg@synaptics.com>
   6 ;; Maintainer: Jay Belanger <jay.p.belanger@gmail.com>
   7
   8 ;; This file is part of GNU Emacs.
   9
  10 ;; GNU Emacs is free software: you can redistribute it and/or modify
  11 ;; it under the terms of the GNU General Public License as published by
  12 ;; the Free Software Foundation, either version 3 of the License, or
  13 ;; (at your option) any later version.
  14
  15 ;; GNU Emacs is distributed in the hope that it will be useful,
  16 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 ;; GNU General Public License for more details.
  19
  20 ;; You should have received a copy of the GNU General Public License
  21 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  22
  23 ;;; Commentary:
  24
  25 ;;; Code:
  26
  27 ;; This file is autoloaded from calc-ext.el.
  28
  29 (require 'calc-ext)
  30 (require 'calc-macs)
  31
  32 ;;; Undo.
  33
  34 ;;;###autoload
  35 (defun calc-undo (n)
  36   (interactive "p")
  37   (when calc-executing-macro
  38     (error "Use C-x e, not X, to run a keyboard macro that uses Undo"))
  39   (if (<= n 0)
  40       (if (< n 0)
  41           (calc-redo (- n))
  42         (calc-last-args 1))
  43     (calc-wrapper
  44      (when (null (nthcdr (1- n) calc-undo-list))
  45        (error "No further undo information available"))
  46      (setq calc-undo-list
  47            (prog1
  48                (nthcdr n calc-undo-list)
  49              (let ((saved-stack-top calc-stack-top))
  50                (let ((calc-stack-top 0))
  51                  (calc-handle-undos calc-undo-list n))
  52                (setq calc-stack-top saved-stack-top))))
  53      (message "Undo!"))))
  54
  55 (defun calc-handle-undos (cl n)
  56   (when (> n 0)
  57     (let ((old-redo calc-redo-list))
  58       (setq calc-undo-list nil)
  59       (calc-handle-undo (car cl))
  60       (setq calc-redo-list (append calc-undo-list old-redo)))
  61     (calc-handle-undos (cdr cl) (1- n))))
  62
  63 (defun calc-handle-undo (list)
  64   (when list
  65        (let ((action (car list)))
  66          (cond
  67           ((eq (car action) 'push)
  68            (calc-pop-stack 1 (nth 1 action) t))
  69           ((eq (car action) 'pop)
  70            (calc-push-list (nth 2 action) (nth 1 action)))
  71           ((eq (car action) 'set)
  72            (calc-record-undo (list 'set (nth 1 action)
  73                                    (symbol-value (nth 1 action))))
  74            (set (nth 1 action) (nth 2 action)))
  75           ((eq (car action) 'store)
  76            (let ((v (intern (nth 1 action))))
  77              (calc-record-undo (list 'store (nth 1 action)
  78                                      (and (boundp v) (symbol-value v))))
  79              (if (y-or-n-p (format "Un-store variable %s? "
  80                                    (calc-var-name (nth 1 action))))
  81                  (progn
  82                    (if (nth 2 action)
  83                        (set v (nth 2 action))
  84                      (makunbound v))
  85                    (calc-refresh-evaltos v)))))
  86           ((eq (car action) 'eval)
  87            (calc-record-undo (append (list 'eval (nth 2 action) (nth 1 action))
  88                                      (cdr (cdr (cdr action)))))
  89            (apply (nth 1 action) (cdr (cdr (cdr action))))))
  90          (calc-handle-undo (cdr list)))))
  91
  92 (defun calc-redo (n)
  93   (interactive "p")
  94   (when calc-executing-macro
  95     (error "Use C-x e, not X, to run a keyboard macro that uses Redo"))
  96   (if (<= n 0)
  97       (calc-undo (- n))
  98     (calc-wrapper
  99      (when (null (nthcdr (1- n) calc-redo-list))
 100        (error "Unable to redo"))
 101      (setq calc-redo-list
 102            (prog1
 103                (nthcdr n calc-redo-list)
 104              (let ((saved-stack-top calc-stack-top))
 105                (let ((calc-stack-top 0))
 106                  (calc-handle-redos calc-redo-list n))
 107                (setq calc-stack-top saved-stack-top))))
 108      (message "Redo!"))))
 109
 110 (defun calc-handle-redos (cl n)
 111   (when (> n 0)
 112     (let ((old-undo calc-undo-list))
 113       (setq calc-undo-list nil)
 114       (calc-handle-undo (car cl))
 115       (setq calc-undo-list (append calc-undo-list old-undo)))
 116     (calc-handle-redos (cdr cl) (1- n))))
 117
 118 (defun calc-last-args (n)
 119   (interactive "p")
 120   (when calc-executing-macro
 121     (error "Use C-x e, not X, to run a keyboard macro that uses last-args"))
 122   (calc-wrapper
 123    (let ((urec (calc-find-last-x calc-undo-list n)))
 124      (if urec
 125          (calc-handle-last-x urec)
 126        (error "Not enough undo information available")))))
 127
 128 (defun calc-handle-last-x (list)
 129   (when list
 130     (let ((action (car list)))
 131       (if (eq (car action) 'pop)
 132           (calc-pop-push-record-list 0 "larg"
 133                                      (delq 'top-of-stack (nth 2 action))))
 134       (calc-handle-last-x (cdr list)))))
 135
 136 (defun calc-find-last-x (ul n)
 137   (when ul
 138     (if (calc-undo-does-pushes (car ul))
 139         (if (<= n 1)
 140             (car ul)
 141           (calc-find-last-x (cdr ul) (1- n)))
 142       (calc-find-last-x (cdr ul) n))))
 143
 144 (defun calc-undo-does-pushes (list)
 145   (and list
 146        (or (eq (car (car list)) 'pop)
 147            (calc-undo-does-pushes (cdr list)))))
 148
 149 (provide 'calc-undo)
 150
 151 ;;; calc-undo.el ends here