[bpt/emacs.git] / lisp / map-ynp.el

;;; map-ynp.el --- General-purpose boolean question-asker.

;;; Copyright (C) 1991, 1992 Free Software Foundation, Inc.

;; 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 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
	 (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))))))

    (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))))))
		  (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))))))
    ;; Clear the last prompt from the minibuffer.
    (message "")
    ;; Return the number of actions that were taken.
    actions))

;;; map-ynp.el ends here
Commit	Line	Data
6594deb0 ER	1	;;; map-ynp.el --- General-purpose boolean question-asker.
6594deb0 ER	2
eea8d4ef ER	3	;;; Copyright (C) 1991, 1992 Free Software Foundation, Inc.
eea8d4ef ER	4
e5167999	5	;; Author: Roland McGrath <roland@gnu.ai.mit.edu>
fd7fa35a	6	;; Keywords: lisp, extensions
e5167999	7
60205e0b RM	8	;;; This program is free software; you can redistribute it and/or modify
60205e0b RM	9	;;; it under the terms of the GNU General Public License as published by
e5167999	10	;;; the Free Software Foundation; either version 2, or (at your option)
60205e0b RM	11	;;; any later version.
	12	;;;
	13	;;; This program is distributed in the hope that it will be useful,
	14	;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	;;; GNU General Public License for more details.
	17	;;;
	18	;;; A copy of the GNU General Public License can be obtained from this
	19	;;; program's author (send electronic mail to roland@ai.mit.edu) or from
	20	;;; the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA
	21	;;; 02139, USA.
e5167999 ER	22
	23	;;; Commentary:
	24
60205e0b RM	25	;;; map-y-or-n-p is a general-purpose question-asking function.
	26	;;; It asks a series of y/n questions (a la y-or-n-p), and decides to
	27	;;; applies an action to each element of a list based on the answer.
	28	;;; The nice thing is that you also get some other possible answers
	29	;;; to use, reminiscent of query-replace: ! to answer y to all remaining
	30	;;; questions; ESC or q to answer n to all remaining questions; . to answer
	31	;;; y once and then n for the remainder; and you can get help with C-h.
	32
e5167999 ER	33	;;; Code:
e5167999 ER	34
60205e0b	35	;;;###autoload
907482b9	36	(defun map-y-or-n-p (prompter actor list &optional help action-alist)
60205e0b	37	"Ask a series of boolean questions.
907482b9	38	Takes args PROMPTER ACTOR LIST, and optional args HELP and ACTION-ALIST.
60205e0b RM	39
	40	LIST is a list of objects, or a function of no arguments to return the next
	41	object or nil.
	42
9fd54390	43	If PROMPTER is a string, the prompt is \(format PROMPTER OBJECT\). If not
03759fe0 RM	44	a string, PROMPTER is a function of one arg (an object from LIST), which
	45	returns a string to be used as the prompt for that object. If the return
	46	value is not a string, it is eval'd to get the answer; it may be nil to
	47	ignore the object, t to act on the object without asking the user, or a
	48	form to do a more complex prompt.
	49
60205e0b RM	50	ACTOR is a function of one arg (an object from LIST),
	51	which gets called with each object that the user answers `yes' for.
	52
	53	If HELP is given, it is a list (OBJECT OBJECTS ACTION),
	54	where OBJECT is a string giving the singular noun for an elt of LIST;
	55	OBJECTS is the plural noun for elts of LIST, and ACTION is a transitive
	56	verb describing ACTOR. The default is \(\"object\" \"objects\" \"act on\"\).
	57
	58	At the prompts, the user may enter y, Y, or SPC to act on that object;
	59	n, N, or DEL to skip that object; ! to act on all following objects;
	60	ESC or q to exit (skip all following objects); . (period) to act on the
	61	current object and then exit; or \\[help-command] to get help.
	62
907482b9 RM	63	If ACTION-ALIST is given, it is an alist (KEY FUNCTION HELP) of extra keys
	64	that will be accepted. KEY is a character; FUNCTION is a function of one
	65	arg (an object from LIST); HELP is a string. When the user hits KEY,
	66	FUNCTION is called. If it returns non-nil, the object is considered
	67	\"acted upon\", and the next object from LIST is processed. If it returns
	68	nil, the prompt is repeated for the same object.
	69
0a2eb25e RS	70	This function uses `query-replace-map' to define the standard responses,
	71	but not all of the responses which `query-replace' understands
	72	are meaningful here.
	73
60205e0b	74	Returns the number of actions taken."
0a2eb25e	75	(let* ((user-keys (if action-alist
08a6ff81 RM	76	(concat (mapconcat (function
	77	(lambda (elt)
	78	(key-description
	79	(char-to-string (car elt)))))
907482b9 RM	80	action-alist ", ")
	81	" ")
	82	""))
03329370 RM	83	;; Make a map that defines each user key as a vector containing
03329370 RM	84	;; its definition.
0a2eb25e	85	(map (cons 'keymap
03329370 RM	86	(append (mapcar (lambda (elt)
03329370 RM	87	(cons (car elt) (vector (nth 1 elt))))
0a2eb25e RS	88	action-alist)
0a2eb25e RS	89	query-replace-map)))
aa228418	90	(actions 0)
0a2eb25e	91	prompt char elt tail def
aa228418 JB	92	(next (if (or (symbolp list)
aa228418 JB	93	(subrp list)
dbc4e1c1	94	(byte-code-function-p list)
aa228418 JB	95	(and (consp list)
	96	(eq (car list) 'lambda)))
	97	(function (lambda ()
	98	(setq elt (funcall list))))
	99	(function (lambda ()
	100	(if list
	101	(progn
	102	(setq elt (car list)
	103	list (cdr list))
	104	t)
	105	nil))))))
0a2eb25e	106
60205e0b RM	107	(if (stringp prompter)
	108	(setq prompter (` (lambda (object)
	109	(format (, prompter) object)))))
ef0ba3e3	110	(while (funcall next)
60205e0b RM	111	(setq prompt (funcall prompter elt))
	112	(if (stringp prompt)
	113	(progn
81eb8fcd	114	(setq quit-flag nil)
60205e0b RM	115	;; Prompt the user about this object.
60205e0b RM	116	(let ((cursor-in-echo-area t))
1586b965	117	(message "%s(y, n, !, ., q, %sor %s) "
907482b9 RM	118	prompt user-keys
907482b9 RM	119	(key-description (char-to-string help-char)))
0a2eb25e	120	(setq char (read-event)))
31ba9d39 RS	121	;; Show the answer to the question.
	122	(message "%s(y, n, !, ., q, %sor %s) %s"
	123	prompt user-keys
	124	(key-description (char-to-string help-char))
	125	(single-key-description char))
0a2eb25e RS	126	(setq def (lookup-key map (vector char)))
0a2eb25e RS	127	(cond ((eq def 'exit)
60205e0b	128	(setq next (function (lambda () nil))))
0a2eb25e	129	((eq def 'act)
60205e0b	130	;; Act on the object.
0a2eb25e	131	(funcall actor elt)
60205e0b	132	(setq actions (1+ actions)))
0a2eb25e	133	((eq def 'skip)
60205e0b RM	134	;; Skip the object.
60205e0b RM	135	)
0a2eb25e	136	((eq def 'act-and-exit)
60205e0b RM	137	;; Act on the object and then exit.
	138	(funcall actor elt)
	139	(setq actions (1+ actions)
	140	next (function (lambda () nil))))
81eb8fcd RS	141	((eq def 'quit)
	142	(setq quit-flag t)
	143	(setq next (` (lambda ()
	144	(setq next '(, next))
	145	'(, elt)))))
0a2eb25e	146	((eq def 'automatic)
0af46a8b RM	147	;; Act on this and all following objects.
	148	(if (eval (funcall prompter elt))
	149	(progn
	150	(funcall actor elt)
	151	(setq actions (1+ actions))))
aa228418	152	(while (funcall next)
0af46a8b	153	(if (eval (funcall prompter elt))
60205e0b RM	154	(progn
60205e0b RM	155	(funcall actor elt)
bed40c39	156	(setq actions (1+ actions))))))
0a2eb25e RS	157	((eq def 'help)
	158	(with-output-to-temp-buffer "Help"
	159	(princ
	160	(let ((object (if help (nth 0 help) "object"))
	161	(objects (if help (nth 1 help) "objects"))
	162	(action (if help (nth 2 help) "act on")))
	163	(concat (format "Type SPC or `y' to %s the current %s;
	164	DEL or `n' to skip the current %s;
	165	! to %s all remaining %s;
	166	ESC or `q' to exit;\n"
	167	action object object action objects)
	168	(mapconcat (function
	169	(lambda (elt)
	170	(format "%c to %s"
	171	(nth 0 elt)
	172	(nth 2 elt))))
	173	action-alist
	174	";\n")
	175	(if action-alist ";\n")
	176	(format "or . (period) to %s \
	177	the current %s and exit."
	178	action object)))))
	179
0af46a8b RM	180	(setq next (` (lambda ()
	181	(setq next '(, next))
	182	'(, elt)))))
03329370	183	((vectorp def)
907482b9	184	;; A user-defined key.
03329370	185	(if (funcall (aref def 0) elt) ;Call its function.
907482b9 RM	186	;; The function has eaten this object.
	187	(setq actions (1+ actions))
	188	;; Regurgitated; try again.
	189	(setq next (` (lambda ()
0a2eb25e RS	190	(setq next '(, next))
0a2eb25e RS	191	'(, elt))))))
60205e0b RM	192	(t
	193	;; Random char.
	194	(message "Type %s for help."
	195	(key-description (char-to-string help-char)))
	196	(beep)
	197	(sit-for 1)
0af46a8b RM	198	(setq next (` (lambda ()
	199	(setq next '(, next))
	200	'(, elt)))))))
60205e0b RM	201	(if (eval prompt)
60205e0b RM	202	(progn
0af46a8b RM	203	(funcall actor elt)
0af46a8b RM	204	(setq actions (1+ actions))))))
60205e0b RM	205	;; Clear the last prompt from the minibuffer.
	206	(message "")
	207	;; Return the number of actions that were taken.
	208	actions))
6594deb0 ER	209
6594deb0 ER	210	;;; map-ynp.el ends here