;;; help-macro.el --- makes command line help such as help-for-help -*- lexical-binding: t -*- ;; Copyright (C) 1993-1994, 2001-2024 Free Software Foundation, Inc. ;; Author: Lynn Slater ;; Maintainer: emacs-devel@gnu.org ;; Created: Mon Oct 1 11:42:39 1990 ;; Adapted-By: ESR ;; Package: emacs ;; 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 ;; 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. 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 (long-since defunct) GNU Emacs ;; Empire Tool used 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) ;;; Code: (require 'backquote) ;; This needs to be autoloaded because it is used in the ;; make-help-screen macro. Using (bound-and-true-p three-step-help) ;; is not an acceptable alternative, because nothing loads help-macro ;; in a normal session, so any user customization would never be applied. ;;;###autoload (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) (defcustom help-for-help-use-variable-pitch t "If non-nil, `help-for-help' should use `variable-pitch-mode'." :type 'boolean :version "30.1" :group 'help) (defmacro make-help-screen (fname help-line help-text helped-map &optional buffer-name) "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." (declare (indent defun)) `(defun ,fname () "Help command." (interactive) (help--help-screen ,help-line ,help-text ,helped-map ,buffer-name))) ;;;###autoload (defun help--help-screen (help-line help-text helped-map buffer-name) (let ((line-prompt (substitute-command-keys help-line)) (help-buffer-under-preparation t)) (when three-step-help (message "%s" line-prompt)) (let* ((help-screen help-text) ;; 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 (help--key-description-fontified (substring (this-command-keys) 0 -1)) t t help-screen))) (unwind-protect (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 (progn (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)) (pop-to-buffer (or buffer-name " *Metahelp*") nil t) (and (fboundp 'make-frame) (not (eq (window-frame) prev-frame)) (setq new-frame (window-frame) config nil)) (setq buffer-read-only nil) (let ((inhibit-read-only t)) (erase-buffer) (insert (substitute-command-keys help-screen))) (let ((minor-mode-map-alist new-minor-mode-map-alist)) (help-mode) (when help-for-help-use-variable-pitch (variable-pitch-mode)) (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 ?\M-v ?\S-\s deletechar backspace vertical-scroll-bar home end next prior up down)))) (eq (car-safe char) 'switch-frame) (equal key "\M-v")) (condition-case nil (cond ((eq (car-safe char) 'switch-frame) (handle-switch-frame char)) ((memq char '(?\C-v ?\s next end)) (scroll-up)) ((or (memq char '(?\177 ?\M-v ?\S-\s deletechar backspace prior home)) (equal key "\M-v")) (scroll-down)) ((memq char '(down)) (scroll-up 1)) ((memq char '(up)) (scroll-down 1))) (error nil)) (let ((cursor-in-echo-area t) (overriding-local-map local-map)) (frame-toggle-on-screen-keyboard (selected-frame) nil) (setq key (read-key-sequence (format "Type one of listed options%s: " (if (pos-visible-in-window-p (point-max)) "" (concat ", or " (help--key-description-fontified (kbd "")) "/" (help--key-description-fontified (kbd "")) "/" (help--key-description-fontified (kbd "SPC")) "/" (help--key-description-fontified (kbd "DEL")) " to scroll"))) nil nil nil nil ;; Disable ``text conversion''. OS ;; input methods might otherwise chose ;; to insert user input directly into ;; a buffer. t) 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 (progn (when config (set-window-configuration config) (setq config nil)) ;; Temporarily rebind `minor-mode-map-alist' ;; to `new-minor-mode-map-alist' (Bug#10454). (let ((minor-mode-map-alist new-minor-mode-map-alist)) ;; `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))) (unless (equal (key-description key) "C-g") (message (substitute-command-keys (format "No help command is bound to `\\`%s''" (key-description key)))) (ding)))))) (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) ;;; help-macro.el ends here