-;;; map-ynp.el -- General-purpose boolean question-asker.
+;;; map-ynp.el --- General-purpose boolean question-asker.
+
;;; Copyright (C) 1991, 1992 Free Software Foundation, Inc.
-;;; Written by Roland McGrath.
-;;;
+
+;; Author: Roland McGrath <roland@gnu.ai.mit.edu>
+;; Keywords: lisp, extensions
+
;;; This program 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 1, or (at your option)
+;;; the Free Software Foundation; either version 2, or (at your option)
;;; any later version.
;;;
;;; This program is distributed in the hope that it will be useful,
;;; program's author (send electronic mail to roland@ai.mit.edu) or from
;;; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
;;; 02139, USA.
-;;;
+
+;;; Commentary:
+
;;; map-y-or-n-p is a general-purpose question-asking function.
;;; It asks a series of y/n questions (a la y-or-n-p), and decides to
;;; applies an action to each element of a list based on the answer.
;;; questions; ESC or q to answer n to all remaining questions; . to answer
;;; y once and then n for the remainder; and you can get help with C-h.
-(defun map-y-or-n-p-help (object objects action)
- (format "Type SPC or `y' to %s the current %s;
-DEL or `n' to skip the current %s;
-! to %s all remaining %s;
-ESC or `q' to exit;
-or . (period) to %s the current %s and exit."
- action object object action objects action object))
+;;; Code:
;;;###autoload
-(defun map-y-or-n-p (prompter actor list &optional help)
+(defun map-y-or-n-p (prompter actor list &optional help action-alist)
"Ask a series of boolean questions.
-Takes args PROMPTER ACTOR LIST, and optional arg HELP.
+Takes args PROMPTER ACTOR LIST, and optional args HELP and ACTION-ALIST.
LIST is a list of objects, or a function of no arguments to return the next
object or nil.
ignore the object, t to act on the object without asking the user, or a
form to do a more complex prompt.
-
ACTOR is a function of one arg (an object from LIST),
which gets called with each object that the user answers `yes' for.
ESC or q to exit (skip all following objects); . (period) to act on the
current object and then exit; or \\[help-command] to get help.
+If ACTION-ALIST is given, it is an alist (KEY FUNCTION HELP) of extra keys
+that will be accepted. KEY is a character; FUNCTION is a function of one
+arg (an object from LIST); HELP is a string. When the user hits KEY,
+FUNCTION is called. If it returns non-nil, the object is considered
+\"acted upon\", and the next object from LIST is processed. If it returns
+nil, the prompt is repeated for the same object.
+
Returns the number of actions taken."
(let* ((old-help-form help-form)
- (help-form (cons 'map-y-or-n-p-help
- (or help '("object" "objects" "act on"))))
+ (help-form (let ((object (if help (nth 0 help) "object"))
+ (objects (if help (nth 1 help) "objects"))
+ (action (if help (nth 2 help) "act on")))
+ (concat (format "Type SPC or `y' to %s the current %s;
+DEL or `n' to skip the current %s;
+! to %s all remaining %s;
+ESC or `q' to exit;\n"
+ action object object action objects)
+ (mapconcat (function
+ (lambda (elt)
+ (format "%c to %s"
+ (nth 0 elt)
+ (nth 2 elt))))
+ action-alist
+ ";\n")
+ (if action-alist ";\n")
+ (format "or . (period) to %s \
+the current %s and exit."
+ action object))))
+ (user-keys (if action-alist
+ (concat (mapconcat (function
+ (lambda (elt)
+ (key-description
+ (char-to-string (car elt)))))
+ action-alist ", ")
+ " ")
+ ""))
(actions 0)
- prompt
- char
- elt
+ prompt char elt tail
(next (if (or (symbolp list)
(subrp list)
(compiled-function-p list)
(progn
;; Prompt the user about this object.
(let ((cursor-in-echo-area t))
- (message "%s(y, n, ! ., q, or %s)"
- prompt (key-description (char-to-string help-char)))
+ (message "%s(y, n, !, ., q, %sor %s) "
+ prompt user-keys
+ (key-description (char-to-string help-char)))
(setq char (read-char)))
(cond ((or (= ?q char)
(= ?\e char))
(setq next (` (lambda ()
(setq next '(, next))
'(, elt)))))
+ ((setq tail (assq char action-alist))
+ ;; A user-defined key.
+ (if (funcall (nth 1 tail) elt) ;Call its function.
+ ;; The function has eaten this object.
+ (setq actions (1+ actions))
+ ;; Regurgitated; try again.
+ (setq next (` (lambda ()
+ (setq next '(, next))
+ '(, elt))))))
(t
;; Random char.
(message "Type %s for help."
(message "")
;; Return the number of actions that were taken.
actions))
+
+;;; map-ynp.el ends here