;;; help-macro.el --- makes command line help such as help-for-help
;; Copyright (C) 1993, 1994 Free Software Foundation, Inc.
;; Author: Lynn Slater <email@example.com>
;; Maintainer: FSF
;; Created: Mon Oct 1 11:42:39 1990
;; Adapted-By: ESR
;; 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, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;; 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.
;; The name of this package was changed from help-screen.el to
;; help-macro.el in order to fit in a 14-character limit.
;;-> *********************** Example of use *********************************
;;-> "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."
;;-> (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
(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."
(defmacro make-help-screen (fname help-line help-text helped-map)
"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"))))
(defun ,doc-fn () ,help-text)
(defun ,fname ()
(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.
config new-frame key char)
(if (string-match "%THIS-KEY%" help-screen)
(replace-match (key-description (substring (this-command-keys) 0 -1))
t t help-screen)))
(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]))
(setq key (let ((overriding-local-map local-map))
;; 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))
(setq config (current-window-configuration))
(and (fboundp 'make-frame)
(not (eq (window-frame (selected-window))
(setq new-frame (window-frame (selected-window))
(setq buffer-read-only nil)
(while (or (memq char (append help-event-list
(cons help-char '(?? ?\C-v ?\ ?\177 delete backspace vertical-scroll-bar ?\M-v))))
(eq (car-safe char) 'switch-frame)
(equal key "\M-v"))
(if (eq (car-safe char) 'switch-frame)
(if (memq char '(?\C-v ?\ ))
(if (or (memq char '(?\177 ?\M-v
(equal key "\M-v"))
(let ((cursor-in-echo-area t)
(setq key (read-key-sequence
(format "Type one of the options listed%s: "
"" ", 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.
;; Mouse clicks are not part of the help feature,
;; so reexecute them in the standard environment.
(if (listp char)
(cons char unread-command-events)
(let ((defn (lookup-key local-map key)))
(setq config nil)))
(progn (iconify-frame new-frame)
(setq new-frame nil)))
(if new-frame (iconify-frame new-frame))
;;; help-macro.el ends here