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mirror of https://git.savannah.gnu.org/git/emacs.git synced 2024-12-16 09:50:25 +00:00
emacs/lisp/calc/calc-undo.el
Paul Eggert bc511a64f6 Prefer HTTPS to FTP and HTTP in documentation
Most of this change is to boilerplate commentary such as license URLs.
This change was prompted by ftp://ftp.gnu.org's going-away party,
planned for November.  Change these FTP URLs to https://ftp.gnu.org
instead.  Make similar changes for URLs to other organizations moving
away from FTP.  Also, change HTTP to HTTPS for URLs to gnu.org and
fsf.org when this works, as this will further help defend against
man-in-the-middle attacks (for this part I omitted the MS-DOS and
MS-Windows sources and the test tarballs to keep the workload down).
HTTPS is not fully working to lists.gnu.org so I left those URLs alone
for now.
2017-09-13 15:54:37 -07:00

151 lines
4.5 KiB
EmacsLisp

;;; calc-undo.el --- undo functions for Calc
;; Copyright (C) 1990-1993, 2001-2017 Free Software Foundation, Inc.
;; Author: David Gillespie <daveg@synaptics.com>
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <https://www.gnu.org/licenses/>.
;;; Commentary:
;;; Code:
;; This file is autoloaded from calc-ext.el.
(require 'calc-ext)
(require 'calc-macs)
;;; Undo.
;;;###autoload
(defun calc-undo (n)
(interactive "p")
(when calc-executing-macro
(error "Use C-x e, not X, to run a keyboard macro that uses Undo"))
(if (<= n 0)
(if (< n 0)
(calc-redo (- n))
(calc-last-args 1))
(calc-wrapper
(when (null (nthcdr (1- n) calc-undo-list))
(error "No further undo information available"))
(setq calc-undo-list
(prog1
(nthcdr n calc-undo-list)
(let ((saved-stack-top calc-stack-top))
(let ((calc-stack-top 0))
(calc-handle-undos calc-undo-list n))
(setq calc-stack-top saved-stack-top))))
(message "Undo!"))))
(defun calc-handle-undos (cl n)
(when (> n 0)
(let ((old-redo calc-redo-list))
(setq calc-undo-list nil)
(calc-handle-undo (car cl))
(setq calc-redo-list (append calc-undo-list old-redo)))
(calc-handle-undos (cdr cl) (1- n))))
(defun calc-handle-undo (list)
(when list
(let ((action (car list)))
(cond
((eq (car action) 'push)
(calc-pop-stack 1 (nth 1 action) t))
((eq (car action) 'pop)
(calc-push-list (nth 2 action) (nth 1 action)))
((eq (car action) 'set)
(calc-record-undo (list 'set (nth 1 action)
(symbol-value (nth 1 action))))
(set (nth 1 action) (nth 2 action)))
((eq (car action) 'store)
(let ((v (intern (nth 1 action))))
(calc-record-undo (list 'store (nth 1 action)
(and (boundp v) (symbol-value v))))
(if (y-or-n-p (format "Un-store variable %s? "
(calc-var-name (nth 1 action))))
(progn
(if (nth 2 action)
(set v (nth 2 action))
(makunbound v))
(calc-refresh-evaltos v)))))
((eq (car action) 'eval)
(calc-record-undo (append (list 'eval (nth 2 action) (nth 1 action))
(cdr (cdr (cdr action)))))
(apply (nth 1 action) (cdr (cdr (cdr action))))))
(calc-handle-undo (cdr list)))))
(defun calc-redo (n)
(interactive "p")
(when calc-executing-macro
(error "Use C-x e, not X, to run a keyboard macro that uses Redo"))
(if (<= n 0)
(calc-undo (- n))
(calc-wrapper
(when (null (nthcdr (1- n) calc-redo-list))
(error "Unable to redo"))
(setq calc-redo-list
(prog1
(nthcdr n calc-redo-list)
(let ((saved-stack-top calc-stack-top))
(let ((calc-stack-top 0))
(calc-handle-redos calc-redo-list n))
(setq calc-stack-top saved-stack-top))))
(message "Redo!"))))
(defun calc-handle-redos (cl n)
(when (> n 0)
(let ((old-undo calc-undo-list))
(setq calc-undo-list nil)
(calc-handle-undo (car cl))
(setq calc-undo-list (append calc-undo-list old-undo)))
(calc-handle-redos (cdr cl) (1- n))))
(defun calc-last-args (n)
(interactive "p")
(when calc-executing-macro
(error "Use C-x e, not X, to run a keyboard macro that uses last-args"))
(calc-wrapper
(let ((urec (calc-find-last-x calc-undo-list n)))
(if urec
(calc-handle-last-x urec)
(error "Not enough undo information available")))))
(defun calc-handle-last-x (list)
(when list
(let ((action (car list)))
(if (eq (car action) 'pop)
(calc-pop-push-record-list 0 "larg"
(delq 'top-of-stack (nth 2 action))))
(calc-handle-last-x (cdr list)))))
(defun calc-find-last-x (ul n)
(when ul
(if (calc-undo-does-pushes (car ul))
(if (<= n 1)
(car ul)
(calc-find-last-x (cdr ul) (1- n)))
(calc-find-last-x (cdr ul) n))))
(defun calc-undo-does-pushes (list)
(and list
(or (eq (car (car list)) 'pop)
(calc-undo-does-pushes (cdr list)))))
(provide 'calc-undo)
;;; calc-undo.el ends here