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1 | ;;; map-ynp.el --- General-purpose boolean question-asker. |
2 | ||
03759fe0 | 3 | ;;; Copyright (C) 1991, 1992 Free Software Foundation, Inc. |
60205e0b RM |
4 | ;;; Written by Roland McGrath. |
5 | ;;; | |
6 | ;;; This program is free software; you can redistribute it and/or modify | |
7 | ;;; it under the terms of the GNU General Public License as published by | |
8 | ;;; the Free Software Foundation; either version 1, or (at your option) | |
9 | ;;; any later version. | |
10 | ;;; | |
11 | ;;; This program is distributed in the hope that it will be useful, | |
12 | ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | ;;; GNU General Public License for more details. | |
15 | ;;; | |
16 | ;;; A copy of the GNU General Public License can be obtained from this | |
17 | ;;; program's author (send electronic mail to roland@ai.mit.edu) or from | |
18 | ;;; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA | |
19 | ;;; 02139, USA. | |
20 | ;;; | |
21 | ;;; map-y-or-n-p is a general-purpose question-asking function. | |
22 | ;;; It asks a series of y/n questions (a la y-or-n-p), and decides to | |
23 | ;;; applies an action to each element of a list based on the answer. | |
24 | ;;; The nice thing is that you also get some other possible answers | |
25 | ;;; to use, reminiscent of query-replace: ! to answer y to all remaining | |
26 | ;;; questions; ESC or q to answer n to all remaining questions; . to answer | |
27 | ;;; y once and then n for the remainder; and you can get help with C-h. | |
28 | ||
29 | (defun map-y-or-n-p-help (object objects action) | |
30 | (format "Type SPC or `y' to %s the current %s; | |
31 | DEL or `n' to skip the current %s; | |
32 | ! to %s all remaining %s; | |
33 | ESC or `q' to exit; | |
34 | or . (period) to %s the current %s and exit." | |
35 | action object object action objects action object)) | |
36 | ||
37 | ;;;###autoload | |
38 | (defun map-y-or-n-p (prompter actor list &optional help) | |
39 | "Ask a series of boolean questions. | |
40 | Takes args PROMPTER ACTOR LIST, and optional arg HELP. | |
41 | ||
42 | LIST is a list of objects, or a function of no arguments to return the next | |
43 | object or nil. | |
44 | ||
9fd54390 | 45 | If PROMPTER is a string, the prompt is \(format PROMPTER OBJECT\). If not |
03759fe0 RM |
46 | a string, PROMPTER is a function of one arg (an object from LIST), which |
47 | returns a string to be used as the prompt for that object. If the return | |
48 | value is not a string, it is eval'd to get the answer; it may be nil to | |
49 | ignore the object, t to act on the object without asking the user, or a | |
50 | form to do a more complex prompt. | |
51 | ||
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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 | Returns the number of actions taken." | |
aa228418 JB |
67 | (let* ((old-help-form help-form) |
68 | (help-form (cons 'map-y-or-n-p-help | |
69 | (or help '("object" "objects" "act on")))) | |
70 | (actions 0) | |
71 | prompt | |
72 | char | |
73 | elt | |
74 | (next (if (or (symbolp list) | |
75 | (subrp list) | |
76 | (compiled-function-p list) | |
77 | (and (consp list) | |
78 | (eq (car list) 'lambda))) | |
79 | (function (lambda () | |
80 | (setq elt (funcall list)))) | |
81 | (function (lambda () | |
82 | (if list | |
83 | (progn | |
84 | (setq elt (car list) | |
85 | list (cdr list)) | |
86 | t) | |
87 | nil)))))) | |
60205e0b RM |
88 | (if (stringp prompter) |
89 | (setq prompter (` (lambda (object) | |
90 | (format (, prompter) object))))) | |
ef0ba3e3 | 91 | (while (funcall next) |
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92 | (setq prompt (funcall prompter elt)) |
93 | (if (stringp prompt) | |
94 | (progn | |
95 | ;; Prompt the user about this object. | |
96 | (let ((cursor-in-echo-area t)) | |
97 | (message "%s(y, n, ! ., q, or %s)" | |
98 | prompt (key-description (char-to-string help-char))) | |
99 | (setq char (read-char))) | |
100 | (cond ((or (= ?q char) | |
101 | (= ?\e char)) | |
102 | (setq next (function (lambda () nil)))) | |
103 | ((or (= ?y char) | |
104 | (= ?Y char) | |
105 | (= ? char)) | |
106 | ;; Act on the object. | |
107 | (let ((help-form old-help-form)) | |
108 | (funcall actor elt)) | |
109 | (setq actions (1+ actions))) | |
110 | ((or (= ?n char) | |
111 | (= ?N char) | |
112 | (= ?\^? char)) | |
113 | ;; Skip the object. | |
114 | ) | |
115 | ((= ?. char) | |
116 | ;; Act on the object and then exit. | |
117 | (funcall actor elt) | |
118 | (setq actions (1+ actions) | |
119 | next (function (lambda () nil)))) | |
120 | ((= ?! char) | |
0af46a8b RM |
121 | ;; Act on this and all following objects. |
122 | (if (eval (funcall prompter elt)) | |
123 | (progn | |
124 | (funcall actor elt) | |
125 | (setq actions (1+ actions)))) | |
aa228418 | 126 | (while (funcall next) |
0af46a8b | 127 | (if (eval (funcall prompter elt)) |
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128 | (progn |
129 | (funcall actor elt) | |
bed40c39 | 130 | (setq actions (1+ actions)))))) |
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131 | ((= ?? char) |
132 | (setq unread-command-char help-char) | |
0af46a8b RM |
133 | (setq next (` (lambda () |
134 | (setq next '(, next)) | |
135 | '(, elt))))) | |
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136 | (t |
137 | ;; Random char. | |
138 | (message "Type %s for help." | |
139 | (key-description (char-to-string help-char))) | |
140 | (beep) | |
141 | (sit-for 1) | |
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142 | (setq next (` (lambda () |
143 | (setq next '(, next)) | |
144 | '(, elt))))))) | |
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145 | (if (eval prompt) |
146 | (progn | |
0af46a8b RM |
147 | (funcall actor elt) |
148 | (setq actions (1+ actions)))))) | |
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149 | ;; Clear the last prompt from the minibuffer. |
150 | (message "") | |
151 | ;; Return the number of actions that were taken. | |
152 | actions)) | |
6594deb0 ER |
153 | |
154 | ;;; map-ynp.el ends here |