Update years in copyright notice; nfc.
[bpt/emacs.git] / lisp / help-macro.el
index 04699ae..cc78bd7 100644 (file)
@@ -1,12 +1,12 @@
-;;; help-macro.el --- Makes command line help such as help-for-help
+;;; help-macro.el --- makes command line help such as help-for-help
 
-;; Copyright (C) 1993 Free Software Foundation, Inc.
+;; Copyright (C) 1993, 1994, 2002, 2003, 2004,
+;;   2005, 2006 Free Software Foundation, Inc.
 
 ;; Author: Lynn Slater <lrs@indetech.com>
-;; Created: : Mon Oct  1 11:42:39 1990
+;; Maintainer: FSF
+;; Created: Mon Oct  1 11:42:39 1990
 ;; Adapted-By: ESR
-;; Last Modified By: Lynn Slater x2048
-;; Last Modified On: Mon Sep 23 14:40:19 1991
 
 ;; This file is part of GNU Emacs.
 
 ;; GNU General Public License for more details.
 
 ;; You should have received a copy of the GNU General Public License
-;; along with GNU Emacs; see the file COPYING.  If not, write to
-;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
+;; along with GNU Emacs; see the file COPYING.  If not, write to the
+;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+;; Boston, MA 02110-1301, USA.
 
 ;;; Commentary:
-;;
-;;     This file supplies the macro make-help-screen which constructs
+
+;; This file supplies the macro make-help-screen which constructs
 ;; single character dispatching with browsable help such as that provided
 ;; by help-for-help. This can be used to make many modes easier to use; for
-;; example, the Gnu Emacs Empire Tool uses this for every "nested" mode map
+;; example, the GNU Emacs Empire Tool uses this for every "nested" mode map
 ;; called from the main mode map.
 
 ;;       The name of this package was changed from help-screen.el to
@@ -44,7 +45,7 @@
 ;;->
 ;;->c  Redistribute civs from overfull sectors into connected underfull ones
 ;;->     The functions typically named by empire-ideal-civ-fcn control
-;;->          based in part on empire-sector-civ-threshold  
+;;->          based in part on empire-sector-civ-threshold
 ;;->m  Redistribute military using levels given by empire-ideal-mil-fcn
 ;;->p  Redistribute excess population to highways for max pop growth
 ;;->     Excess is any sector so full babies will not be born.
 
 ;;; Change Log:
 ;;
-;; 22-Jan-1991         Lynn Slater x2048       
+;; 22-Jan-1991         Lynn Slater x2048
 ;;    Last Modified: Mon Oct  1 11:43:52 1990 #3 (Lynn Slater)
 ;;    documented better
 
 ;;; Code:
 
-(provide 'help-macro)
 (require 'backquote)
 
+;;;###autoload
+(defcustom three-step-help nil
+  "*Non-nil means give more info about Help command in three steps.
+The three steps are simple prompt, prompt with all options,
+and window listing and describing the options.
+A value of nil means skip the middle step, so that
+\\[help-command] \\[help-command] gives the window that lists the options."
+  :type 'boolean
+  :group 'help)
+
 (defmacro make-help-screen (fname help-line help-text helped-map)
-  "Constructs function FNAME that when invoked shows HELP-LINE and if a help
-character is requested, shows HELP-TEXT. The user is prompted for a character
-from the HELPED-MAP and the corresponding interactive function is executed."
-  (` (defun (, fname) ()
-          (, help-text)
+  "Construct help-menu function name FNAME.
+When invoked, FNAME shows HELP-LINE and reads a command using HELPED-MAP.
+If the command is the help character, FNAME displays HELP-TEXT
+and continues trying to read a command using HELPED-MAP.
+If HELP-TEXT contains the sequence `%THIS-KEY%', that is replaced
+with the key sequence that invoked FNAME.
+When FNAME finally does get a command, it executes that command
+and then returns."
+ (let ((doc-fn (intern (concat (symbol-name fname) "-doc"))))
+  `(progn
+    (defun ,doc-fn () ,help-text)
+    (defun ,fname ()
+          "Help command."
           (interactive)
           (let ((line-prompt
-                 (substitute-command-keys (, help-line))))
-            (message line-prompt)
-            (let ((char (read-char)))
-              (if (or (= char ??) (= char help-char))
-                  (save-window-excursion
-                    (switch-to-buffer-other-window "*Help*")
-                    (erase-buffer)
-                    (insert (documentation (quote (, fname))))
-                    (goto-char (point-min))
-                    (while (memq char (cons help-char '(?? ?\C-v ?\ ?\177 ?\M-v)))
-                      (if (memq char '(?\C-v ?\ ))
-                          (scroll-up))
-                      (if (memq char '(?\177 ?\M-v))
-                          (scroll-down))
-                      (message "%s%s: "
-                               line-prompt
-                               (if (pos-visible-in-window-p (point-max))
-                                   "" " or Space to scroll"))
-                      (let ((cursor-in-echo-area t))
-                        (setq char (read-char))))))
-              (let ((defn (cdr (assq (downcase char) (, helped-map)))))
-                (if defn
-                    (if (keymapp defn)
-                        (error "sorry, this command cannot be run from the help screen. Start over.")
-                      (call-interactively defn))
-                  (ding))))))
-     ))
-
-;;; help-macro.el
+                 (substitute-command-keys ,help-line)))
+            (if three-step-help
+                (message "%s" line-prompt))
+            (let* ((help-screen (documentation (quote ,doc-fn)))
+                   ;; We bind overriding-local-map for very small
+                   ;; sections, *excluding* where we switch buffers
+                   ;; and where we execute the chosen help command.
+                   (local-map (make-sparse-keymap))
+                   (minor-mode-map-alist nil)
+                   (prev-frame (selected-frame))
+                   config new-frame key char)
+              (if (string-match "%THIS-KEY%" help-screen)
+                  (setq help-screen
+                        (replace-match (key-description (substring (this-command-keys) 0 -1))
+                                       t t help-screen)))
+              (unwind-protect
+                  (progn
+                    (setcdr local-map ,helped-map)
+                    (define-key local-map [t] 'undefined)
+                    ;; Make the scroll bar keep working normally.
+                    (define-key local-map [vertical-scroll-bar]
+                      (lookup-key global-map [vertical-scroll-bar]))
+                    (if three-step-help
+                        (progn
+                          (setq key (let ((overriding-local-map local-map))
+                                      (read-key-sequence nil)))
+                          ;; Make the HELP key translate to C-h.
+                          (if (lookup-key function-key-map key)
+                              (setq key (lookup-key function-key-map key)))
+                          (setq char (aref key 0)))
+                      (setq char ??))
+                    (if (or (eq char ??) (eq char help-char)
+                            (memq char help-event-list))
+                        (progn
+                          (setq config (current-window-configuration))
+                          (switch-to-buffer-other-window "*Help*")
+                          (and (fboundp 'make-frame)
+                               (not (eq (window-frame (selected-window))
+                                        prev-frame))
+                               (setq new-frame (window-frame (selected-window))
+                                     config nil))
+                          (setq buffer-read-only nil)
+                          (let ((inhibit-read-only t))
+                            (erase-buffer)
+                            (insert help-screen))
+                          (help-mode)
+                          (goto-char (point-min))
+                          (while (or (memq char (append help-event-list
+                                                        (cons help-char '(?? ?\C-v ?\s ?\177 delete backspace vertical-scroll-bar ?\M-v))))
+                                     (eq (car-safe char) 'switch-frame)
+                                     (equal key "\M-v"))
+                            (condition-case nil
+                                (progn
+                                  (if (eq (car-safe char) 'switch-frame)
+                                      (handle-switch-frame char))
+                                  (if (memq char '(?\C-v ?\ ))
+                                      (scroll-up))
+                                  (if (or (memq char '(?\177 ?\M-v
+                                                       delete backspace))
+                                          (equal key "\M-v"))
+                                      (scroll-down)))
+                              (error nil))
+                            (let ((cursor-in-echo-area t)
+                                  (overriding-local-map local-map))
+                              (setq key (read-key-sequence
+                                         (format "Type one of the options listed%s: "
+                                                 (if (pos-visible-in-window-p
+                                                      (point-max))
+                                                     "" ", or SPACE or DEL to scroll")))
+                                    char (aref key 0)))
+
+                            ;; If this is a scroll bar command, just run it.
+                            (when (eq char 'vertical-scroll-bar)
+                              (command-execute (lookup-key local-map key) nil key)))))
+                    ;; We don't need the prompt any more.
+                    (message "")
+                    ;; Mouse clicks are not part of the help feature,
+                    ;; so reexecute them in the standard environment.
+                    (if (listp char)
+                        (setq unread-command-events
+                              (cons char unread-command-events)
+                              config nil)
+                      (let ((defn (lookup-key local-map key)))
+                        (if defn
+                            (progn
+                              (if config
+                                  (progn
+                                    (set-window-configuration config)
+                                    (setq config nil)))
+                              (if new-frame
+                                  (progn (iconify-frame new-frame)
+                                         (setq new-frame nil)))
+                              (call-interactively defn))
+                          (ding)))))
+                (if new-frame (iconify-frame new-frame))
+                (if config
+                    (set-window-configuration config))))))
+     )))
+
+(provide 'help-macro)
 
+;;; arch-tag: 59fee949-1686-485a-8a05-83418073e257
+;;; help-macro.el ends here