lisp/help-macro.el

   1 ;;; help-macro.el --- Makes command line help such as help-for-help
   2
   3 ;; Copyright (C) 1993 Free Software Foundation, Inc.
   4
   5 ;; Author: Lynn Slater <lrs@indetech.com>
   6 ;; Created: : Mon Oct  1 11:42:39 1990
   7 ;; Adapted-By: ESR
   8 ;; Last Modified By: Lynn Slater x2048
   9 ;; Last Modified On: Mon Sep 23 14:40:19 1991
  10
  11 ;; This file is part of GNU Emacs.
  12
  13 ;; GNU Emacs is free software; you can redistribute it and/or modify
  14 ;; it under the terms of the GNU General Public License as published by
  15 ;; the Free Software Foundation; either version 2, or (at your option)
  16 ;; any later version.
  17
  18 ;; GNU Emacs is distributed in the hope that it will be useful,
  19 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  20 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21 ;; GNU General Public License for more details.
  22
  23 ;; You should have received a copy of the GNU General Public License
  24 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  25 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  26
  27 ;;; Commentary:
  28 ;;
  29 ;;      This file supplies the macro make-help-screen which constructs
  30 ;; single character dispatching with browsable help such as that provided
  31 ;; by help-for-help. This can be used to make many modes easier to use; for
  32 ;; example, the Gnu Emacs Empire Tool uses this for every "nested" mode map
  33 ;; called from the main mode map.
  34
  35 ;;       The name of this package was changed from help-screen.el to
  36 ;; help-macro.el in order to fit in a 14-character limit.
  37
  38 ;;-> ***********************  Example of use *********************************
  39
  40 ;;->(make-help-screen help-for-empire-redistribute-map
  41 ;;->              "c:civ m:mil p:population f:food ?"
  42 ;;->              "You have discovered the GEET redistribution commands
  43 ;;->   From here, you can use the following options:
  44 ;;->
  45 ;;->c   Redistribute civs from overfull sectors into connected underfull ones
  46 ;;->      The functions typically named by empire-ideal-civ-fcn control
  47 ;;->          based in part on empire-sector-civ-threshold
  48 ;;->m   Redistribute military using levels given by empire-ideal-mil-fcn
  49 ;;->p   Redistribute excess population to highways for max pop growth
  50 ;;->      Excess is any sector so full babies will not be born.
  51 ;;->f   Even out food on highways to highway min and leave levels
  52 ;;->      This is good to pump max food to all warehouses/dist pts
  53 ;;->
  54 ;;->
  55 ;;->Use \\[help-for-empire-redistribute-map] for help on redistribution.
  56 ;;->Use \\[help-for-empire-extract-map] for help on data extraction.
  57 ;;->Please use \\[describe-key] to find out more about any of the other keys."
  58 ;;->              empire-shell-redistribute-map)
  59
  60 ;;->  (define-key c-mp "\C-h" 'help-for-empire-redistribute-map)
  61 ;;->  (define-key c-mp help-character 'help-for-empire-redistribute-map)
  62
  63 ;;; Change Log:
  64 ;;
  65 ;; 22-Jan-1991          Lynn Slater x2048
  66 ;;    Last Modified: Mon Oct  1 11:43:52 1990 #3 (Lynn Slater)
  67 ;;    documented better
  68
  69 ;;; Code:
  70
  71 (provide 'help-macro)
  72 (require 'backquote)
  73
  74 ;;;###autoload
  75 (defvar three-step-help nil
  76   "*Non-nil means give more info about Help command in three steps.
  77 The three steps are simple prompt, prompt with all options,
  78 and window listing and describing the options.
  79 A value of nil means skip the middle step, so that
  80 \\[help-command] \\[help-command] gives the window that lists the options.")
  81
  82 (defmacro make-help-screen (fname help-line help-text helped-map)
  83   "Construct help-menu function name FNAME.
  84 When invoked, FNAME shows HELP-LINE and reads a command using HELPED-MAP.
  85 If the command is the help character is requested, FNAME displays HELP-TEXT
  86 and continues trying to read a command using HELPED-MAP.
  87 When FNAME finally does get a command, it executes that command
  88 and then returns."
  89   (` (defun (, fname) ()
  90            (, help-text)
  91            (interactive)
  92            (let ((line-prompt
  93                   (substitute-command-keys (, help-line))))
  94              (if three-step-help
  95                  (message line-prompt))
  96              (let* ((help-screen (documentation (quote (, fname))))
  97                     (overriding-local-map (make-sparse-keymap))
  98                     (minor-mode-map-alist nil)
  99                     config key char)
 100                (unwind-protect
 101                    (progn
 102                      (setcdr overriding-local-map (, helped-map))
 103                      (define-key overriding-local-map [t] 'undefined)
 104                      (if three-step-help
 105                          (setq key (read-key-sequence nil)
 106                                char (aref key 0))
 107                        (setq char ??))
 108                      (if (or (eq char ??) (eq char help-char))
 109                          (progn
 110                            (setq config (current-window-configuration))
 111                            (switch-to-buffer-other-window "*Help*")
 112                            (erase-buffer)
 113                            (insert help-screen)
 114                            (goto-char (point-min))
 115                            (while (or (memq char (cons help-char '(?? ?\C-v ?\ ?\177 delete ?\M-v)))
 116                                       (equal key "\M-v"))
 117                              (condition-case nil
 118                                  (progn
 119                                    (if (memq char '(?\C-v ?\ ))
 120                                        (scroll-up))
 121                                    (if (or (memq char '(?\177 ?\M-v delete))
 122                                            (equal key "\M-v"))
 123                                        (scroll-down)))
 124                                (error nil))
 125                              (let ((cursor-in-echo-area t))
 126                                (setq key (read-key-sequence
 127                                           (format "Type one of the options listed%s: "
 128                                                   (if (pos-visible-in-window-p
 129                                                        (point-max))
 130                                                       "" " or Space to scroll")))
 131                                      char (aref key 0))))))
 132                      ;; Mouse clicks are not part of the help feature,
 133                      ;; so reexecute them in the standard environment.
 134                      (if (listp char)
 135                          (setq unread-command-events
 136                                (cons char unread-command-events)
 137                                config nil)
 138                        (let ((defn (key-binding key)))
 139                          (if defn
 140                              (progn
 141                                (if config
 142                                    (progn
 143                                      (set-window-configuration config)
 144                                      (setq config nil)))
 145                                (setq overriding-local-map nil)
 146                                (call-interactively defn))
 147                            (ding)))))
 148                  (if config
 149                      (set-window-configuration config))))))
 150      ))
 151
 152 ;;; help-macro.el
 153