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;;; help-macro.el --- makes command line help such as help-for-help
;; Copyright (C) 1993, 1994, 2001, 2002, 2003, 2004,
;; 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
;; Author: Lynn Slater <>
;; 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 3 of the License, 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
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see <>.
;;; 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.
;; 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 *********************************
;;->(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:
(require 'backquote)
(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)
"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 nil)
(defun ,fname ()
"Help command."
(let ((line-prompt
(substitute-command-keys ,help-line)))
(when 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))
(new-minor-mode-map-alist minor-mode-map-alist)
(prev-frame (selected-frame))
config new-frame key char)
(when (string-match "%THIS-KEY%" help-screen)
(setq help-screen
(replace-match (key-description
(substring (this-command-keys) 0 -1))
t t help-screen)))
(let ((minor-mode-map-alist nil))
(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
(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 ??))
(when (or (eq char ??) (eq char help-char)
(memq char help-event-list))
(setq config (current-window-configuration))
(switch-to-buffer-other-window "*Help*")
(and (fboundp 'make-frame)
(not (eq (window-frame (selected-window))
(setq new-frame (window-frame (selected-window))
config nil))
(setq buffer-read-only nil)
(let ((inhibit-read-only t))
(insert help-screen))
(let ((minor-mode-map-alist new-minor-mode-map-alist))
(setq new-minor-mode-map-alist minor-mode-map-alist))
(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
((eq (car-safe char) 'switch-frame)
(handle-switch-frame char))
((memq char '(?\C-v ?\s))
((or (memq char '(?\177 ?\M-v delete backspace))
(equal key "\M-v"))
(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
"" ", 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
(when config
(set-window-configuration config)
(setq config nil))
;; `defn' must make sure that its frame is
;; selected, so we won't iconify it below.
(call-interactively defn)
(when new-frame
;; Do not iconify the selected frame.
(unless (eq new-frame (selected-frame))
(iconify-frame new-frame))
(setq new-frame nil)))
(when config
(set-window-configuration config))
(when new-frame
(iconify-frame new-frame))
(setq minor-mode-map-alist new-minor-mode-map-alist))))))))
(provide 'help-macro)
;; arch-tag: 59fee949-1686-485a-8a05-83418073e257
;;; help-macro.el ends here
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