lisp/emacs-lisp/map-ynp.el

   1 ;;; map-ynp.el --- general-purpose boolean question-asker  -*- lexical-binding:t -*-
   2
   3 ;; Copyright (C) 1991-1995, 2000-2018 Free Software Foundation, Inc.
   4
   5 ;; Author: Roland McGrath <roland@gnu.org>
   6 ;; Maintainer: emacs-devel@gnu.org
   7 ;; Keywords: lisp, extensions
   8 ;; Package: emacs
   9
  10 ;; This file is part of GNU Emacs.
  11
  12 ;; GNU Emacs is free software: you can redistribute it and/or modify
  13 ;; it under the terms of the GNU General Public License as published by
  14 ;; the Free Software Foundation, either version 3 of the License, or
  15 ;; (at your option) any later version.
  16
  17 ;; GNU Emacs is distributed in the hope that it will be useful,
  18 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ;; GNU General Public License for more details.
  21
  22 ;; You should have received a copy of the GNU General Public License
  23 ;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
  24
  25 ;;; Commentary:
  26
  27 ;; map-y-or-n-p is a general-purpose question-asking function.
  28 ;; It asks a series of y/n questions (a la y-or-n-p), and decides to
  29 ;; apply an action to each element of a list based on the answer.
  30 ;; The nice thing is that you also get some other possible answers
  31 ;; to use, reminiscent of query-replace: ! to answer y to all remaining
  32 ;; questions; ESC or q to answer n to all remaining questions; . to answer
  33 ;; y once and then n for the remainder; and you can get help with C-h.
  34
  35 ;;; Code:
  36
  37 (declare-function x-popup-dialog "menu.c" (position contents &optional header))
  38
  39 (defun map-y-or-n-p (prompter actor list &optional help action-alist
  40                               no-cursor-in-echo-area)
  41   "Ask a series of boolean questions.
  42 Takes args PROMPTER ACTOR LIST, and optional args HELP and ACTION-ALIST.
  43
  44 LIST is a list of objects, or a function of no arguments to return the next
  45 object or nil.
  46
  47 If PROMPTER is a string, the prompt is \(format PROMPTER OBJECT).  If not
  48 a string, PROMPTER is a function of one arg (an object from LIST), which
  49 returns a string to be used as the prompt for that object.  If the return
  50 value is not a string, it may be nil to ignore the object or non-nil to act
  51 on the object without asking the user.
  52
  53 ACTOR is a function of one arg (an object from LIST),
  54 which gets called with each object that the user answers `yes' for.
  55
  56 If HELP is given, it is a list (OBJECT OBJECTS ACTION),
  57 where OBJECT is a string giving the singular noun for an elt of LIST;
  58 OBJECTS is the plural noun for elts of LIST, and ACTION is a transitive
  59 verb describing ACTOR.  The default is \(\"object\" \"objects\" \"act on\").
  60
  61 At the prompts, the user may enter y, Y, or SPC to act on that object;
  62 n, N, or DEL to skip that object; ! to act on all following objects;
  63 ESC or q to exit (skip all following objects); . (period) to act on the
  64 current object and then exit; or \\[help-command] to get help.
  65
  66 If ACTION-ALIST is given, it is an alist (KEY FUNCTION HELP) of extra keys
  67 that will be accepted.  KEY is a character; FUNCTION is a function of one
  68 arg (an object from LIST); HELP is a string.  When the user hits KEY,
  69 FUNCTION is called.  If it returns non-nil, the object is considered
  70 \"acted upon\", and the next object from LIST is processed.  If it returns
  71 nil, the prompt is repeated for the same object.
  72
  73 Final optional argument NO-CURSOR-IN-ECHO-AREA non-nil says not to set
  74 `cursor-in-echo-area' while prompting.
  75
  76 This function uses `query-replace-map' to define the standard responses,
  77 but not all of the responses which `query-replace' understands
  78 are meaningful here.
  79
  80 Returns the number of actions taken."
  81   (let* ((actions 0)
  82          user-keys mouse-event map prompt char elt def
  83          ;; Non-nil means we should use mouse menus to ask.
  84          use-menus
  85          delayed-switch-frame
  86          ;; Rebind other-window-scroll-buffer so that subfunctions can set
  87          ;; it temporarily, without risking affecting the caller.
  88          (other-window-scroll-buffer other-window-scroll-buffer)
  89          (next (if (functionp list)
  90                    (lambda () (setq elt (funcall list)))
  91                  (lambda () (when list
  92                               (setq elt (pop list))
  93                               t))))
  94          (try-again (lambda ()
  95                       (let ((x next))
  96                         (setq next (lambda () (setq next x) elt))))))
  97     (if (and (listp last-nonmenu-event)
  98              use-dialog-box)
  99         ;; Make a list describing a dialog box.
 100         (let ((objects (if help (capitalize (nth 1 help))))
 101               (action (if help (capitalize (nth 2 help)))))
 102           (setq map `(("Yes" . act) ("No" . skip)
 103                       ,@(mapcar (lambda (elt)
 104                                   (cons (with-syntax-table
 105                                             text-mode-syntax-table
 106                                           (capitalize (nth 2 elt)))
 107                                         (vector (nth 1 elt))))
 108                                 action-alist)
 109                       (,(if help (concat action " This But No More")
 110                           "Do This But No More") . act-and-exit)
 111                       (,(if help (concat action " All " objects)
 112                           "Do All") . automatic)
 113                       ("No For All" . exit))
 114                 use-menus t
 115                 mouse-event last-nonmenu-event))
 116       (setq user-keys (if action-alist
 117                           (concat (mapconcat (lambda (elt)
 118                                                (key-description
 119                                                 (vector (car elt))))
 120                                              action-alist ", ")
 121                                   " ")
 122                         "")
 123             ;; Make a map that defines each user key as a vector containing
 124             ;; its definition.
 125             map
 126             (let ((map (make-sparse-keymap)))
 127               (set-keymap-parent map query-replace-map)
 128               (dolist (elt action-alist)
 129                 (define-key map (vector (car elt)) (vector (nth 1 elt))))
 130               map)))
 131     (unwind-protect
 132         (progn
 133           (if (stringp prompter)
 134               (setq prompter (let ((prompter prompter))
 135                                (lambda (object)
 136                                  (format prompter object)))))
 137           (while (funcall next)
 138             (setq prompt (funcall prompter elt))
 139             (cond ((stringp prompt)
 140                    ;; Prompt the user about this object.
 141                    (setq quit-flag nil)
 142                    (if use-menus
 143                        (setq def (or (x-popup-dialog (or mouse-event use-menus)
 144                                                      (cons prompt map))
 145                                      'quit))
 146                      ;; Prompt in the echo area.
 147                      (let ((cursor-in-echo-area (not no-cursor-in-echo-area)))
 148                        (message (apply 'propertize "%s(y, n, !, ., q, %sor %s) "
 149                                        minibuffer-prompt-properties)
 150                                 prompt user-keys
 151                                 (key-description (vector help-char)))
 152                        (if minibuffer-auto-raise
 153                            (raise-frame (window-frame (minibuffer-window))))
 154                        (while (progn
 155                                 (setq char (read-event))
 156                                 ;; If we get -1, from end of keyboard
 157                                 ;; macro, try again.
 158                                 (equal char -1)))
 159                        ;; Show the answer to the question.
 160                        (message "%s(y, n, !, ., q, %sor %s) %s"
 161                                 prompt user-keys
 162                                 (key-description (vector help-char))
 163                                 (single-key-description char)))
 164                      (setq def (lookup-key map (vector char))))
 165                    (cond ((eq def 'exit)
 166                           (setq next (lambda () nil)))
 167                          ((eq def 'act)
 168                           ;; Act on the object.
 169                           (funcall actor elt)
 170                           (setq actions (1+ actions)))
 171                          ((eq def 'skip)
 172                           ;; Skip the object.
 173                           )
 174                          ((eq def 'act-and-exit)
 175                           ;; Act on the object and then exit.
 176                           (funcall actor elt)
 177                           (setq actions (1+ actions)
 178                                 next (lambda () nil)))
 179                          ((eq def 'quit)
 180                           (setq quit-flag t)
 181                           (funcall try-again))
 182                          ((eq def 'automatic)
 183                           ;; Act on this and all following objects.
 184                           (if (funcall prompter elt)
 185                               (progn
 186                                 (funcall actor elt)
 187                                 (setq actions (1+ actions))))
 188                           (while (funcall next)
 189                             (if (funcall prompter elt)
 190                                 (progn
 191                                   (funcall actor elt)
 192                                   (setq actions (1+ actions))))))
 193                          ((eq def 'help)
 194                           (with-output-to-temp-buffer "*Help*"
 195                             (princ
 196                              (let ((object (if help (nth 0 help) "object"))
 197                                    (objects (if help (nth 1 help) "objects"))
 198                                    (action (if help (nth 2 help) "act on")))
 199                                (concat
 200                                 (format-message "\
 201 Type SPC or `y' to %s the current %s;
 202 DEL or `n' to skip the current %s;
 203 RET or `q' to give up on the %s (skip all remaining %s);
 204 C-g to quit (cancel the whole command);
 205 ! to %s all remaining %s;\n"
 206                                         action object object action objects action
 207                                         objects)
 208                                 (mapconcat (function
 209                                             (lambda (elt)
 210                                               (format "%s to %s"
 211                                                       (single-key-description
 212                                                        (nth 0 elt))
 213                                                       (nth 2 elt))))
 214                                            action-alist
 215                                            ";\n")
 216                                 (if action-alist ";\n")
 217                                 (format "or . (period) to %s \
 218 the current %s and exit."
 219                                         action object))))
 220                             (with-current-buffer standard-output
 221                               (help-mode)))
 222
 223                           (funcall try-again))
 224                          ((and (symbolp def) (commandp def))
 225                           (call-interactively def)
 226                           ;; Regurgitated; try again.
 227                           (funcall try-again))
 228                          ((vectorp def)
 229                           ;; A user-defined key.
 230                           (if (funcall (aref def 0) elt) ;Call its function.
 231                               ;; The function has eaten this object.
 232                               (setq actions (1+ actions))
 233                             ;; Regurgitated; try again.
 234                             (funcall try-again)))
 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                           (funcall try-again))
 240                          (t
 241                           ;; Random char.
 242                           (message "Type %s for help."
 243                                    (key-description (vector help-char)))
 244                           (beep)
 245                           (sit-for 1)
 246                           (funcall try-again))))
 247                   (prompt
 248                    (funcall actor elt)
 249                    (setq actions (1+ actions))))))
 250       (if delayed-switch-frame
 251           (setq unread-command-events
 252                 (cons delayed-switch-frame unread-command-events))))
 253     ;; Clear the last prompt from the minibuffer.
 254     (let ((message-log-max nil))
 255       (message ""))
 256     ;; Return the number of actions that were taken.
 257     actions))
 258
 259 ;;; map-ynp.el ends here