lisp/map-ynp.el

   1 ;;; map-ynp.el --- general-purpose boolean question-asker
   2
   3 ;; Copyright (C) 1991, 1992, 1993, 1994, 1995, 2000 Free Software Foundation, Inc.
   4
   5 ;; Author: Roland McGrath <roland@gnu.org>
   6 ;; Maintainer: FSF
   7 ;; Keywords: lisp, extensions
   8
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to the
  23 ;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  24 ;; Boston, MA 02111-1307, USA.
  25
  26 ;;; Commentary:
  27
  28 ;; map-y-or-n-p is a general-purpose question-asking function.
  29 ;; It asks a series of y/n questions (a la y-or-n-p), and decides to
  30 ;; apply an action to each element of a list based on the answer.
  31 ;; The nice thing is that you also get some other possible answers
  32 ;; to use, reminiscent of query-replace: ! to answer y to all remaining
  33 ;; questions; ESC or q to answer n to all remaining questions; . to answer
  34 ;; y once and then n for the remainder; and you can get help with C-h.
  35
  36 ;;; Code:
  37
  38 (defun map-y-or-n-p (prompter actor list &optional help action-alist
  39                               no-cursor-in-echo-area)
  40   "Ask a series of boolean questions.
  41 Takes args PROMPTER ACTOR LIST, and optional args HELP and ACTION-ALIST.
  42
  43 LIST is a list of objects, or a function of no arguments to return the next
  44 object or nil.
  45
  46 If PROMPTER is a string, the prompt is \(format PROMPTER OBJECT\).  If not
  47 a string, PROMPTER is a function of one arg (an object from LIST), which
  48 returns a string to be used as the prompt for that object.  If the return
  49 value is not a string, it may be nil to ignore the object or non-nil to act
  50 on the object without asking the user.
  51
  52 ACTOR is a function of one arg (an object from LIST),
  53 which gets called with each object that the user answers `yes' for.
  54
  55 If HELP is given, it is a list (OBJECT OBJECTS ACTION),
  56 where OBJECT is a string giving the singular noun for an elt of LIST;
  57 OBJECTS is the plural noun for elts of LIST, and ACTION is a transitive
  58 verb describing ACTOR.  The default is \(\"object\" \"objects\" \"act on\"\).
  59
  60 At the prompts, the user may enter y, Y, or SPC to act on that object;
  61 n, N, or DEL to skip that object; ! to act on all following objects;
  62 ESC or q to exit (skip all following objects); . (period) to act on the
  63 current object and then exit; or \\[help-command] to get help.
  64
  65 If ACTION-ALIST is given, it is an alist (KEY FUNCTION HELP) of extra keys
  66 that will be accepted.  KEY is a character; FUNCTION is a function of one
  67 arg (an object from LIST); HELP is a string.  When the user hits KEY,
  68 FUNCTION is called.  If it returns non-nil, the object is considered
  69 \"acted upon\", and the next object from LIST is processed.  If it returns
  70 nil, the prompt is repeated for the same object.
  71
  72 Final optional argument NO-CURSOR-IN-ECHO-AREA non-nil says not to set
  73 `cursor-in-echo-area' while prompting.
  74
  75 This function uses `query-replace-map' to define the standard responses,
  76 but not all of the responses which `query-replace' understands
  77 are meaningful here.
  78
  79 Returns the number of actions taken."
  80   (let* ((actions 0)
  81          user-keys mouse-event map prompt char elt tail def
  82          ;; Non-nil means we should use mouse menus to ask.
  83          use-menus
  84          delayed-switch-frame
  85          (next (if (or (and list (symbolp list))
  86                        (subrp list)
  87                        (byte-code-function-p list)
  88                        (and (consp list)
  89                             (eq (car list) 'lambda)))
  90                    (function (lambda ()
  91                                (setq elt (funcall list))))
  92                  (function (lambda ()
  93                              (if list
  94                                  (progn
  95                                    (setq elt (car list)
  96                                          list (cdr list))
  97                                    t)
  98                                nil))))))
  99     (if (and (listp last-nonmenu-event)
 100              use-dialog-box)
 101         ;; Make a list describing a dialog box.
 102         (let ((object (if help (capitalize (nth 0 help))))
 103               (objects (if help (capitalize (nth 1 help))))
 104               (action (if help (capitalize (nth 2 help)))))
 105           (setq map `(("Yes" . act) ("No" . skip) ("Quit" . exit)
 106                       (,(if help (concat action " " object " And Quit")
 107                           "Do it and Quit") . act-and-exit)
 108                       (,(if help (concat action " All " objects)
 109                           "Do All") . automatic)
 110                       ,@(mapcar (lambda (elt)
 111                                   (cons (capitalize (nth 2 elt))
 112                                         (vector (nth 1 elt))))
 113                                 action-alist))
 114                 use-menus t
 115                 mouse-event last-nonmenu-event))
 116       (setq user-keys (if action-alist
 117                           (concat (mapconcat (function
 118                                               (lambda (elt)
 119                                                 (key-description
 120                                                  (char-to-string (car elt)))))
 121                                              action-alist ", ")
 122                                   " ")
 123                         "")
 124             ;; Make a map that defines each user key as a vector containing
 125             ;; its definition.
 126             map (cons 'keymap
 127                       (append (mapcar (lambda (elt)
 128                                         (cons (car elt) (vector (nth 1 elt))))
 129                                       action-alist)
 130                               query-replace-map))))
 131     (unwind-protect
 132         (progn
 133           (if (stringp prompter)
 134               (setq prompter `(lambda (object)
 135                                 (format ,prompter object))))
 136           (while (funcall next)
 137             (setq prompt (funcall prompter elt))
 138             (cond ((stringp prompt)
 139                    ;; Prompt the user about this object.
 140                    (setq quit-flag nil)
 141                    (if use-menus
 142                        (setq def (or (x-popup-dialog (or mouse-event use-menus)
 143                                                      (cons prompt map))
 144                                      'quit))
 145                      ;; Prompt in the echo area.
 146                      (let ((cursor-in-echo-area (not no-cursor-in-echo-area))
 147                            (message-log-max nil))
 148                        (message "%s(y, n, !, ., q, %sor %s) "
 149                                 prompt user-keys
 150                                 (key-description (vector help-char)))
 151                        (if minibuffer-auto-raise
 152                            (raise-frame (window-frame (minibuffer-window))))
 153                        (while (progn
 154                                 (setq char (read-event))
 155                                 ;; If we get -1, from end of keyboard
 156                                 ;; macro, try again.
 157                                 (equal char -1)))
 158                        ;; Show the answer to the question.
 159                        (message "%s(y, n, !, ., q, %sor %s) %s"
 160                                 prompt user-keys
 161                                 (key-description (vector help-char))
 162                                 (single-key-description char)))
 163                      (setq def (lookup-key map (vector char))))
 164                    (cond ((eq def 'exit)
 165                           (setq next (function (lambda () nil))))
 166                          ((eq def 'act)
 167                           ;; Act on the object.
 168                           (funcall actor elt)
 169                           (setq actions (1+ actions)))
 170                          ((eq def 'skip)
 171                           ;; Skip the object.
 172                           )
 173                          ((eq def 'act-and-exit)
 174                           ;; Act on the object and then exit.
 175                           (funcall actor elt)
 176                           (setq actions (1+ actions)
 177                                 next (function (lambda () nil))))
 178                          ((or (eq def 'quit) (eq def 'exit-prefix))
 179                           (setq quit-flag t)
 180                           (setq next `(lambda ()
 181                                         (setq next ',next)
 182                                         ',elt)))
 183                          ((eq def 'automatic)
 184                           ;; Act on this and all following objects.
 185                           (if (funcall prompter elt)
 186                               (progn
 187                                 (funcall actor elt)
 188                                 (setq actions (1+ actions))))
 189                           (while (funcall next)
 190                             (if (funcall prompter elt)
 191                                 (progn
 192                                   (funcall actor elt)
 193                                   (setq actions (1+ actions))))))
 194                          ((eq def 'help)
 195                           (with-output-to-temp-buffer "*Help*"
 196                             (princ
 197                              (let ((object (if help (nth 0 help) "object"))
 198                                    (objects (if help (nth 1 help) "objects"))
 199                                    (action (if help (nth 2 help) "act on")))
 200                                (concat
 201                                 (format "Type SPC or `y' to %s the current %s;
 202 DEL or `n' to skip the current %s;
 203 RET or `q' to exit (skip all remaining %s);
 204 ! to %s all remaining %s;
 205 ESC or `q' to exit;\n"
 206                                         action object object objects action
 207                                         objects)
 208                                 (mapconcat (function
 209                                             (lambda (elt)
 210                                               (format "%c to %s"
 211                                                       (nth 0 elt)
 212                                                       (nth 2 elt))))
 213                                            action-alist
 214                                            ";\n")
 215                                 (if action-alist ";\n")
 216                                 (format "or . (period) to %s \
 217 the current %s and exit."
 218                                         action object))))
 219                             (save-excursion
 220                               (set-buffer standard-output)
 221                               (help-mode)))
 222
 223                           (setq next `(lambda ()
 224                                        (setq next ',next)
 225                                        ',elt)))
 226                          ((vectorp def)
 227                           ;; A user-defined key.
 228                           (if (funcall (aref def 0) elt) ;Call its function.
 229                               ;; The function has eaten this object.
 230                               (setq actions (1+ actions))
 231                             ;; Regurgitated; try again.
 232                             (setq next `(lambda ()
 233                                          (setq next ',next)
 234                                          ',elt))))
 235                          ((and (consp char)
 236                                (eq (car char) 'switch-frame))
 237                           ;; switch-frame event.  Put it off until we're done.
 238                           (setq delayed-switch-frame char)
 239                           (setq next `(lambda ()
 240                                        (setq next ',next)
 241                                        ',elt)))
 242                          (t
 243                           ;; Random char.
 244                           (message "Type %s for help."
 245                                    (key-description (vector help-char)))
 246                           (beep)
 247                           (sit-for 1)
 248                           (setq next `(lambda ()
 249                                        (setq next ',next)
 250                                        ',elt)))))
 251                   (prompt
 252                    (funcall actor elt)
 253                    (setq actions (1+ actions))))))
 254       (if delayed-switch-frame
 255           (setq unread-command-events
 256                 (cons delayed-switch-frame unread-command-events))))
 257     ;; Clear the last prompt from the minibuffer.
 258     (let ((message-log-max nil))
 259       (message ""))
 260     ;; Return the number of actions that were taken.
 261     actions))
 262
 263 ;;; map-ynp.el ends here