;;; map-ynp.el --- General-purpose boolean question-asker. ;;; Copyright (C) 1991, 1992 Free Software Foundation, Inc. ;; Author: Roland McGrath ;; 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 2, or (at your option) ;;; any later version. ;;; ;;; This program 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. ;;; ;;; A copy of the GNU General Public License can be obtained from this ;;; 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. ;;; The nice thing is that you also get some other possible answers ;;; to use, reminiscent of query-replace: ! to answer y to all remaining ;;; 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. ;;; Code: ;;;###autoload (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 args HELP and ACTION-ALIST. LIST is a list of objects, or a function of no arguments to return the next object or nil. If PROMPTER is a string, the prompt is \(format PROMPTER OBJECT\). If not a string, PROMPTER is a function of one arg (an object from LIST), which returns a string to be used as the prompt for that object. If the return value is not a string, it is eval'd to get the answer; it may be nil to 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. If HELP is given, it is a list (OBJECT OBJECTS ACTION), where OBJECT is a string giving the singular noun for an elt of LIST; OBJECTS is the plural noun for elts of LIST, and ACTION is a transitive verb describing ACTOR. The default is \(\"object\" \"objects\" \"act on\"\). At the prompts, the user may enter y, Y, or SPC to act on that object; n, N, or DEL to skip that object; ! to act on all following objects; 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. This function uses `query-replace-map' to define the standard responses, but not all of the responses which `query-replace' understands are meaningful here. Returns the number of actions taken." (let* ((user-keys (if action-alist (concat (mapconcat (function (lambda (elt) (key-description (char-to-string (car elt))))) action-alist ", ") " ") "")) ;; Make a map that defines each user key as a vector containing ;; its definition. (map (cons 'keymap (append (mapcar (lambda (elt) (cons (car elt) (vector (nth 1 elt)))) action-alist) query-replace-map))) (actions 0) prompt char elt tail def delayed-switch-frame (next (if (or (symbolp list) (subrp list) (byte-code-function-p list) (and (consp list) (eq (car list) 'lambda))) (function (lambda () (setq elt (funcall list)))) (function (lambda () (if list (progn (setq elt (car list) list (cdr list)) t) nil)))))) (unwind-protect (progn (if (stringp prompter) (setq prompter (` (lambda (object) (format (, prompter) object))))) (while (funcall next) (setq prompt (funcall prompter elt)) (if (stringp prompt) (progn (setq quit-flag nil) ;; Prompt the user about this object. (let ((cursor-in-echo-area t)) (message "%s(y, n, !, ., q, %sor %s) " prompt user-keys (key-description (char-to-string help-char))) (setq char (read-event))) ;; Show the answer to the question. (message "%s(y, n, !, ., q, %sor %s) %s" prompt user-keys (key-description (char-to-string help-char)) (single-key-description char)) (setq def (lookup-key map (vector char))) (cond ((eq def 'exit) (setq next (function (lambda () nil)))) ((eq def 'act) ;; Act on the object. (funcall actor elt) (setq actions (1+ actions))) ((eq def 'skip) ;; Skip the object. ) ((eq def 'act-and-exit) ;; Act on the object and then exit. (funcall actor elt) (setq actions (1+ actions) next (function (lambda () nil)))) ((eq def 'quit) (setq quit-flag t) (setq next (` (lambda () (setq next '(, next)) '(, elt))))) ((eq def 'automatic) ;; Act on this and all following objects. (if (eval (funcall prompter elt)) (progn (funcall actor elt) (setq actions (1+ actions)))) (while (funcall next) (if (eval (funcall prompter elt)) (progn (funcall actor elt) (setq actions (1+ actions)))))) ((eq def 'help) (with-output-to-temp-buffer "*Help*" (princ (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))))) (setq next (` (lambda () (setq next '(, next)) '(, elt))))) ((vectorp def) ;; A user-defined key. (if (funcall (aref def 0) elt) ;Call its function. ;; The function has eaten this object. (setq actions (1+ actions)) ;; Regurgitated; try again. (setq next (` (lambda () (setq next '(, next)) '(, elt)))))) ((and (consp char) (eq (car char) 'switch-frame)) ;; switch-frame event. Put it off until we're done. (setq delayed-switch-frame char) (setq next (` (lambda () (setq next '(, next)) '(, elt))))) (t ;; Random char. (message "Type %s for help." (key-description (char-to-string help-char))) (beep) (sit-for 1) (setq next (` (lambda () (setq next '(, next)) '(, elt))))))) (if (eval prompt) (progn (funcall actor elt) (setq actions (1+ actions))))))) (if delayed-switch-frame (setq unread-command-events (cons delayed-switch-frame unread-command-events)))) ;; Clear the last prompt from the minibuffer. (message "") ;; Return the number of actions that were taken. actions)) ;;; map-ynp.el ends here