code.delx.au - gnu-emacs/blob - lisp/calc/calc-undo.el

   1 ;;; calc-undo.el --- undo functions for Calc
   2
   3 ;; Copyright (C) 1990-1993, 2001-2016 Free Software Foundation, Inc.
   4
   5 ;; Author: David Gillespie <daveg@synaptics.com>
   6
   7 ;; This file is part of GNU Emacs.
   8
   9 ;; GNU Emacs is free software: you can redistribute it and/or modify
  10 ;; it under the terms of the GNU General Public License as published by
  11 ;; the Free Software Foundation, either version 3 of the License, or
  12 ;; (at your option) any later version.
  13
  14 ;; GNU Emacs is distributed in the hope that it will be useful,
  15 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 ;; GNU General Public License for more details.
  18
  19 ;; You should have received a copy of the GNU General Public License
  20 ;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.
  21
  22 ;;; Commentary:
  23
  24 ;;; Code:
  25
  26 ;; This file is autoloaded from calc-ext.el.
  27
  28 (require 'calc-ext)
  29 (require 'calc-macs)
  30
  31 ;;; Undo.
  32
  33 ;;;###autoload
  34 (defun calc-undo (n)
  35   (interactive "p")
  36   (when calc-executing-macro
  37     (error "Use C-x e, not X, to run a keyboard macro that uses Undo"))
  38   (if (<= n 0)
  39       (if (< n 0)
  40           (calc-redo (- n))
  41         (calc-last-args 1))
  42     (calc-wrapper
  43      (when (null (nthcdr (1- n) calc-undo-list))
  44        (error "No further undo information available"))
  45      (setq calc-undo-list
  46            (prog1
  47                (nthcdr n calc-undo-list)
  48              (let ((saved-stack-top calc-stack-top))
  49                (let ((calc-stack-top 0))
  50                  (calc-handle-undos calc-undo-list n))
  51                (setq calc-stack-top saved-stack-top))))
  52      (message "Undo!"))))
  53
  54 (defun calc-handle-undos (cl n)
  55   (when (> n 0)
  56     (let ((old-redo calc-redo-list))
  57       (setq calc-undo-list nil)
  58       (calc-handle-undo (car cl))
  59       (setq calc-redo-list (append calc-undo-list old-redo)))
  60     (calc-handle-undos (cdr cl) (1- n))))
  61
  62 (defun calc-handle-undo (list)
  63   (when list
  64        (let ((action (car list)))
  65          (cond
  66           ((eq (car action) 'push)
  67            (calc-pop-stack 1 (nth 1 action) t))
  68           ((eq (car action) 'pop)
  69            (calc-push-list (nth 2 action) (nth 1 action)))
  70           ((eq (car action) 'set)
  71            (calc-record-undo (list 'set (nth 1 action)
  72                                    (symbol-value (nth 1 action))))
  73            (set (nth 1 action) (nth 2 action)))
  74           ((eq (car action) 'store)
  75            (let ((v (intern (nth 1 action))))
  76              (calc-record-undo (list 'store (nth 1 action)
  77                                      (and (boundp v) (symbol-value v))))
  78              (if (y-or-n-p (format "Un-store variable %s? "
  79                                    (calc-var-name (nth 1 action))))
  80                  (progn
  81                    (if (nth 2 action)
  82                        (set v (nth 2 action))
  83                      (makunbound v))
  84                    (calc-refresh-evaltos v)))))
  85           ((eq (car action) 'eval)
  86            (calc-record-undo (append (list 'eval (nth 2 action) (nth 1 action))
  87                                      (cdr (cdr (cdr action)))))
  88            (apply (nth 1 action) (cdr (cdr (cdr action))))))
  89          (calc-handle-undo (cdr list)))))
  90
  91 (defun calc-redo (n)
  92   (interactive "p")
  93   (when calc-executing-macro
  94     (error "Use C-x e, not X, to run a keyboard macro that uses Redo"))
  95   (if (<= n 0)
  96       (calc-undo (- n))
  97     (calc-wrapper
  98      (when (null (nthcdr (1- n) calc-redo-list))
  99        (error "Unable to redo"))
 100      (setq calc-redo-list
 101            (prog1
 102                (nthcdr n calc-redo-list)
 103              (let ((saved-stack-top calc-stack-top))
 104                (let ((calc-stack-top 0))
 105                  (calc-handle-redos calc-redo-list n))
 106                (setq calc-stack-top saved-stack-top))))
 107      (message "Redo!"))))
 108
 109 (defun calc-handle-redos (cl n)
 110   (when (> n 0)
 111     (let ((old-undo calc-undo-list))
 112       (setq calc-undo-list nil)
 113       (calc-handle-undo (car cl))
 114       (setq calc-undo-list (append calc-undo-list old-undo)))
 115     (calc-handle-redos (cdr cl) (1- n))))
 116
 117 (defun calc-last-args (n)
 118   (interactive "p")
 119   (when calc-executing-macro
 120     (error "Use C-x e, not X, to run a keyboard macro that uses last-args"))
 121   (calc-wrapper
 122    (let ((urec (calc-find-last-x calc-undo-list n)))
 123      (if urec
 124          (calc-handle-last-x urec)
 125        (error "Not enough undo information available")))))
 126
 127 (defun calc-handle-last-x (list)
 128   (when list
 129     (let ((action (car list)))
 130       (if (eq (car action) 'pop)
 131           (calc-pop-push-record-list 0 "larg"
 132                                      (delq 'top-of-stack (nth 2 action))))
 133       (calc-handle-last-x (cdr list)))))
 134
 135 (defun calc-find-last-x (ul n)
 136   (when ul
 137     (if (calc-undo-does-pushes (car ul))
 138         (if (<= n 1)
 139             (car ul)
 140           (calc-find-last-x (cdr ul) (1- n)))
 141       (calc-find-last-x (cdr ul) n))))
 142
 143 (defun calc-undo-does-pushes (list)
 144   (and list
 145        (or (eq (car (car list)) 'pop)
 146            (calc-undo-does-pushes (cdr list)))))
 147
 148 (provide 'calc-undo)
 149
 150 ;;; calc-undo.el ends here