lisp/help-macro.el

   1 ;;; help-macro.el --- Makes command line help such as help-for-help
   2
   3 ;; Copyright (C) 1993, 1994 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
   9 ;; This file is part of GNU Emacs.
  10
  11 ;; GNU Emacs is free software; you can redistribute it and/or modify
  12 ;; it under the terms of the GNU General Public License as published by
  13 ;; the Free Software Foundation; either version 2, or (at your option)
  14 ;; any later version.
  15
  16 ;; GNU Emacs is distributed in the hope that it will be useful,
  17 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 ;; GNU General Public License for more details.
  20
  21 ;; You should have received a copy of the GNU General Public License
  22 ;; along with GNU Emacs; see the file COPYING.  If not, write to
  23 ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
  24
  25 ;;; Commentary:
  26 ;;
  27 ;;      This file supplies the macro make-help-screen which constructs
  28 ;; single character dispatching with browsable help such as that provided
  29 ;; by help-for-help. This can be used to make many modes easier to use; for
  30 ;; example, the Gnu Emacs Empire Tool uses this for every "nested" mode map
  31 ;; called from the main mode map.
  32
  33 ;;       The name of this package was changed from help-screen.el to
  34 ;; help-macro.el in order to fit in a 14-character limit.
  35
  36 ;;-> ***********************  Example of use *********************************
  37
  38 ;;->(make-help-screen help-for-empire-redistribute-map
  39 ;;->              "c:civ m:mil p:population f:food ?"
  40 ;;->              "You have discovered the GEET redistribution commands
  41 ;;->   From here, you can use the following options:
  42 ;;->
  43 ;;->c   Redistribute civs from overfull sectors into connected underfull ones
  44 ;;->      The functions typically named by empire-ideal-civ-fcn control
  45 ;;->          based in part on empire-sector-civ-threshold
  46 ;;->m   Redistribute military using levels given by empire-ideal-mil-fcn
  47 ;;->p   Redistribute excess population to highways for max pop growth
  48 ;;->      Excess is any sector so full babies will not be born.
  49 ;;->f   Even out food on highways to highway min and leave levels
  50 ;;->      This is good to pump max food to all warehouses/dist pts
  51 ;;->
  52 ;;->
  53 ;;->Use \\[help-for-empire-redistribute-map] for help on redistribution.
  54 ;;->Use \\[help-for-empire-extract-map] for help on data extraction.
  55 ;;->Please use \\[describe-key] to find out more about any of the other keys."
  56 ;;->              empire-shell-redistribute-map)
  57
  58 ;;->  (define-key c-mp "\C-h" 'help-for-empire-redistribute-map)
  59 ;;->  (define-key c-mp help-character 'help-for-empire-redistribute-map)
  60
  61 ;;; Change Log:
  62 ;;
  63 ;; 22-Jan-1991          Lynn Slater x2048
  64 ;;    Last Modified: Mon Oct  1 11:43:52 1990 #3 (Lynn Slater)
  65 ;;    documented better
  66
  67 ;;; Code:
  68
  69 (provide 'help-macro)
  70 (require 'backquote)
  71
  72 ;;;###autoload
  73 (defvar three-step-help nil
  74   "*Non-nil means give more info about Help command in three steps.
  75 The three steps are simple prompt, prompt with all options,
  76 and window listing and describing the options.
  77 A value of nil means skip the middle step, so that
  78 \\[help-command] \\[help-command] gives the window that lists the options.")
  79
  80 (defmacro make-help-screen (fname help-line help-text helped-map)
  81   "Construct help-menu function name FNAME.
  82 When invoked, FNAME shows HELP-LINE and reads a command using HELPED-MAP.
  83 If the command is the help character, FNAME displays HELP-TEXT
  84 and continues trying to read a command using HELPED-MAP.
  85 When FNAME finally does get a command, it executes that command
  86 and then returns."
  87   (` (defun (, fname) ()
  88            (, help-text)
  89            (interactive)
  90            (let ((line-prompt
  91                   (substitute-command-keys (, help-line))))
  92              (if three-step-help
  93                  (message line-prompt))
  94              (let* ((help-screen (documentation (quote (, fname))))
  95                     ;; We bind overriding-local-map for very small
  96                     ;; sections, *excluding* where we switch buffers
  97                     ;; and where we execute the chosen help command.
  98                     (local-map (make-sparse-keymap))
  99                     (minor-mode-map-alist nil)
 100                     (prev-frame (selected-frame))
 101                     config new-frame key char)
 102                (unwind-protect
 103                    (progn
 104                      (setcdr local-map (, helped-map))
 105                      (define-key local-map [t] 'undefined)
 106                      (if three-step-help
 107                          (progn
 108                            (setq key (let ((overriding-local-map local-map))
 109                                      (read-key-sequence nil)))
 110                            ;; Make the HELP key translate to C-h.
 111                            (if (lookup-key function-key-map key)
 112                                (setq key (lookup-key function-key-map key)))
 113                            (setq char (aref key 0)))
 114                        (setq char ??))
 115                      (if (or (eq char ??) (eq char help-char)
 116                              (memq char help-event-list))
 117                          (progn
 118                            (setq config (current-window-configuration))
 119                            (switch-to-buffer-other-window "*Help*")
 120                            (and (fboundp 'make-frame)
 121                                 (not (eq (window-frame (selected-window))
 122                                          prev-frame))
 123                                 (setq new-frame (window-frame (selected-window))
 124                                       config nil))
 125                            (erase-buffer)
 126                            (insert help-screen)
 127                            (help-mode)
 128                            (goto-char (point-min))
 129                            (while (or (memq char (append help-event-list
 130                                                          (cons help-char '(?? ?\C-v ?\ ?\177 delete backspace ?\M-v))))
 131                                       (eq (car-safe char) 'switch-frame)
 132                                       (equal key "\M-v"))
 133                              (condition-case nil
 134                                  (progn
 135                                    (if (eq (car-safe char) 'switch-frame)
 136                                        (handle-switch-frame char))
 137                                    (if (memq char '(?\C-v ?\ ))
 138                                        (scroll-up))
 139                                    (if (or (memq char '(?\177 ?\M-v
 140                                                         delete backspace))
 141                                            (equal key "\M-v"))
 142                                        (scroll-down)))
 143                                (error nil))
 144                              (let ((cursor-in-echo-area t)
 145                                    (overriding-local-map local-map))
 146                                (setq key (read-key-sequence
 147                                           (format "Type one of the options listed%s: "
 148                                                   (if (pos-visible-in-window-p
 149                                                        (point-max))
 150                                                       "" " or Space to scroll")))
 151                                      char (aref key 0))))))
 152                      ;; Mouse clicks are not part of the help feature,
 153                      ;; so reexecute them in the standard environment.
 154                      (if (listp char)
 155                          (setq unread-command-events
 156                                (cons char unread-command-events)
 157                                config nil)
 158                        (let ((defn (lookup-key local-map key)))
 159                          (if defn
 160                              (progn
 161                                (if config
 162                                    (progn
 163                                      (set-window-configuration config)
 164                                      (setq config nil)))
 165                                (if new-frame
 166                                    (progn (iconify-frame new-frame)
 167                                           (setq new-frame nil)))
 168                                (call-interactively defn))
 169                            (ding)))))
 170                  (if new-frame (iconify-frame new-frame))
 171                  (if config
 172                      (set-window-configuration config))))))
 173      ))
 174
 175 ;;; help-macro.el
 176