Initial revision

lisp/help-macro.el

+;;; help-screen.el --- Makes command line help such as help-for-help
+
+;; Copyright (C) 1993 Free Software Foundation, Inc.
+
+;; Author: Lynn Slater <lrs@indetech.com>
+;; 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 Emacs 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.
+
+;; GNU Emacs 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.
+
+;; 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.
+
+;;; Commentary:
+;;
+;; 	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
+;; called from the main mode map.
+
+;;-> ***********************  Example of use *********************************
+
+;;->(make-help-screen help-for-empire-redistribute-map
+;;->		  "c:civ m:mil p:population f:food ?"
+;;->		  "You have discovered the GEET redistribution commands
+;;->   From here, you can use the following options:
+;;->
+;;->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  
+;;->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.
+;;->f	Even out food on highways to highway min and leave levels
+;;->	  This is good to pump max food to all warehouses/dist pts
+;;->
+;;->
+;;->Use \\[help-for-empire-redistribute-map] for help on redistribution.
+;;->Use \\[help-for-empire-extract-map] for help on data extraction.
+;;->Please use \\[describe-key] to find out more about any of the other keys."
+;;->		  empire-shell-redistribute-map)
+
+;;->  (define-key c-mp "\C-h" 'help-for-empire-redistribute-map)
+;;->  (define-key c-mp help-character 'help-for-empire-redistribute-map)
+
+;;; Change Log:
+;;
+;; 22-Jan-1991		Lynn Slater x2048	
+;;    Last Modified: Mon Oct  1 11:43:52 1990 #3 (Lynn Slater)
+;;    documented better
+
+;;; Code:
+
+(provide 'help-screen)
+(require 'backquote)
+
+(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)
+	   (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-screen.el
+