| 1 | ;; Help commands for Emacs |
| 2 | ;; Copyright (C) 1985, 1986 Free Software Foundation, Inc. |
| 3 | |
| 4 | ;; This file is part of GNU Emacs. |
| 5 | |
| 6 | ;; GNU Emacs is free software; you can redistribute it and/or modify |
| 7 | ;; it under the terms of the GNU General Public License as published by |
| 8 | ;; the Free Software Foundation; either version 1, or (at your option) |
| 9 | ;; any later version. |
| 10 | |
| 11 | ;; GNU Emacs is distributed in the hope that it will be useful, |
| 12 | ;; but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 14 | ;; GNU General Public License for more details. |
| 15 | |
| 16 | ;; You should have received a copy of the GNU General Public License |
| 17 | ;; along with GNU Emacs; see the file COPYING. If not, write to |
| 18 | ;; the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. |
| 19 | |
| 20 | |
| 21 | (defvar help-map (make-sparse-keymap) |
| 22 | "Keymap for characters following the Help key.") |
| 23 | |
| 24 | (define-key global-map "\C-h" 'help-command) |
| 25 | (fset 'help-command help-map) |
| 26 | |
| 27 | (define-key help-map "\C-h" 'help-for-help) |
| 28 | (define-key help-map "?" 'help-for-help) |
| 29 | |
| 30 | (define-key help-map "\C-c" 'describe-copying) |
| 31 | (define-key help-map "\C-d" 'describe-distribution) |
| 32 | (define-key help-map "\C-w" 'describe-no-warranty) |
| 33 | (define-key help-map "a" 'command-apropos) |
| 34 | |
| 35 | (define-key help-map "b" 'describe-bindings) |
| 36 | |
| 37 | (define-key help-map "c" 'describe-key-briefly) |
| 38 | (define-key help-map "k" 'describe-key) |
| 39 | |
| 40 | (define-key help-map "d" 'describe-function) |
| 41 | (define-key help-map "f" 'describe-function) |
| 42 | |
| 43 | (define-key help-map "i" 'info) |
| 44 | |
| 45 | (define-key help-map "l" 'view-lossage) |
| 46 | |
| 47 | (define-key help-map "m" 'describe-mode) |
| 48 | |
| 49 | (define-key help-map "\C-n" 'view-emacs-news) |
| 50 | (define-key help-map "n" 'view-emacs-news) |
| 51 | |
| 52 | (define-key help-map "s" 'describe-syntax) |
| 53 | |
| 54 | (define-key help-map "t" 'help-with-tutorial) |
| 55 | |
| 56 | (define-key help-map "w" 'where-is) |
| 57 | |
| 58 | (define-key help-map "v" 'describe-variable) |
| 59 | |
| 60 | (defun help-with-tutorial () |
| 61 | "Select the Emacs learn-by-doing tutorial." |
| 62 | (interactive) |
| 63 | (let ((file (expand-file-name "~/TUTORIAL"))) |
| 64 | (delete-other-windows) |
| 65 | (if (get-file-buffer file) |
| 66 | (switch-to-buffer (get-file-buffer file)) |
| 67 | (switch-to-buffer (create-file-buffer file)) |
| 68 | (setq buffer-file-name file) |
| 69 | (setq default-directory (expand-file-name "~/")) |
| 70 | (setq auto-save-file-name nil) |
| 71 | (insert-file-contents (expand-file-name "TUTORIAL" exec-directory)) |
| 72 | (goto-char (point-min)) |
| 73 | (search-forward "\n<<") |
| 74 | (beginning-of-line) |
| 75 | (delete-region (point) (progn (end-of-line) (point))) |
| 76 | (newline (- (window-height (selected-window)) |
| 77 | (count-lines (point-min) (point)) |
| 78 | 6)) |
| 79 | (goto-char (point-min)) |
| 80 | (set-buffer-modified-p nil)))) |
| 81 | |
| 82 | (defun describe-key-briefly (key) |
| 83 | "Print the name of the function KEY invokes. KEY is a string." |
| 84 | (interactive "kDescribe key briefly: ") |
| 85 | (let ((defn (key-binding key))) |
| 86 | (if (or (null defn) (integerp defn)) |
| 87 | (message "%s is undefined" (key-description key)) |
| 88 | (message "%s runs the command %s" |
| 89 | (key-description key) |
| 90 | (if (symbolp defn) defn (prin1-to-string defn)))))) |
| 91 | |
| 92 | (defun print-help-return-message (&optional function) |
| 93 | "Display or return message saying how to restore windows after help command. |
| 94 | Computes a message and applies the argument FUNCTION to it. |
| 95 | If FUNCTION is nil, applies `message' to it, thus printing it." |
| 96 | (and (not (get-buffer-window standard-output)) |
| 97 | (funcall (or function 'message) |
| 98 | (substitute-command-keys |
| 99 | (if (one-window-p t) |
| 100 | (if pop-up-windows |
| 101 | "Type \\[delete-other-windows] to remove help window." |
| 102 | "Type \\[switch-to-buffer] RET to remove help window.") |
| 103 | "Type \\[switch-to-buffer-other-window] RET to restore old contents of help window."))))) |
| 104 | |
| 105 | (defun describe-key (key) |
| 106 | "Display documentation of the function KEY invokes. KEY is a string." |
| 107 | (interactive "kDescribe key: ") |
| 108 | (let ((defn (key-binding key))) |
| 109 | (if (or (null defn) (integerp defn)) |
| 110 | (message "%s is undefined" (key-description key)) |
| 111 | (with-output-to-temp-buffer "*Help*" |
| 112 | (prin1 defn) |
| 113 | (princ ":\n") |
| 114 | (if (documentation defn) |
| 115 | (princ (documentation defn)) |
| 116 | (princ "not documented")) |
| 117 | (print-help-return-message))))) |
| 118 | |
| 119 | (defun describe-mode () |
| 120 | "Display documentation of current major mode." |
| 121 | (interactive) |
| 122 | (with-output-to-temp-buffer "*Help*" |
| 123 | (princ mode-name) |
| 124 | (princ " Mode:\n") |
| 125 | (princ (documentation major-mode)) |
| 126 | (print-help-return-message))) |
| 127 | |
| 128 | (defun describe-distribution () |
| 129 | "Display info on how to obtain the latest version of GNU Emacs." |
| 130 | (interactive) |
| 131 | (find-file-read-only |
| 132 | (expand-file-name "DISTRIB" exec-directory))) |
| 133 | |
| 134 | (defun describe-copying () |
| 135 | "Display info on how you may redistribute copies of GNU Emacs." |
| 136 | (interactive) |
| 137 | (find-file-read-only |
| 138 | (expand-file-name "COPYING" exec-directory)) |
| 139 | (goto-char (point-min))) |
| 140 | |
| 141 | (defun describe-no-warranty () |
| 142 | "Display info on all the kinds of warranty Emacs does NOT have." |
| 143 | (interactive) |
| 144 | (describe-copying) |
| 145 | (let (case-fold-search) |
| 146 | (search-forward "NO WARRANTY") |
| 147 | (recenter 0))) |
| 148 | |
| 149 | (defun view-emacs-news () |
| 150 | "Display info on recent changes to Emacs." |
| 151 | (interactive) |
| 152 | (find-file-read-only (expand-file-name "NEWS" exec-directory))) |
| 153 | |
| 154 | (defun view-lossage () |
| 155 | "Display last 100 input keystrokes." |
| 156 | (interactive) |
| 157 | (with-output-to-temp-buffer "*Help*" |
| 158 | (princ (key-description (recent-keys))) |
| 159 | (save-excursion |
| 160 | (set-buffer standard-output) |
| 161 | (goto-char (point-min)) |
| 162 | (while (progn (move-to-column 50) (not (eobp))) |
| 163 | (search-forward " " nil t) |
| 164 | (insert "\n"))) |
| 165 | (print-help-return-message))) |
| 166 | |
| 167 | (defun help-for-help () |
| 168 | "You have typed C-h, the help character. Type a Help option: |
| 169 | |
| 170 | A command-apropos. Give a substring, and see a list of commands |
| 171 | (functions interactively callable) that contain |
| 172 | that substring. See also the apropos command. |
| 173 | B describe-bindings. Display table of all key bindings. |
| 174 | C describe-key-briefly. Type a command key sequence; |
| 175 | it prints the function name that sequence runs. |
| 176 | F describe-function. Type a function name and get documentation of it. |
| 177 | I info. The info documentation reader. |
| 178 | K describe-key. Type a command key sequence; |
| 179 | it displays the full documentation. |
| 180 | L view-lossage. Shows last 100 characters you typed. |
| 181 | M describe-mode. Print documentation of current major mode, |
| 182 | which describes the commands peculiar to it. |
| 183 | N view-emacs-news. Shows emacs news file. |
| 184 | S describe-syntax. Display contents of syntax table, plus explanations |
| 185 | T help-with-tutorial. Select the Emacs learn-by-doing tutorial. |
| 186 | V describe-variable. Type name of a variable; |
| 187 | it displays the variable's documentation and value. |
| 188 | W where-is. Type command name; it prints which keystrokes |
| 189 | invoke that command. |
| 190 | C-c print Emacs copying permission (General Public License). |
| 191 | C-d print Emacs ordering information. |
| 192 | C-n print news of recent Emacs changes. |
| 193 | C-w print information on absence of warranty for GNU Emacs." |
| 194 | (interactive) |
| 195 | (message |
| 196 | "A B C F I K L M N S T V W C-c C-d C-n C-w. Type C-h again for more help: ") |
| 197 | (let ((char (read-char))) |
| 198 | (if (or (= char ?\C-h) (= char ??)) |
| 199 | (save-window-excursion |
| 200 | (switch-to-buffer "*Help*") |
| 201 | (erase-buffer) |
| 202 | (insert (documentation 'help-for-help)) |
| 203 | (goto-char (point-min)) |
| 204 | (while (memq char '(?\C-h ?? ?\C-v ?\ ?\177 ?\M-v)) |
| 205 | (if (memq char '(?\C-v ?\ )) |
| 206 | (scroll-up)) |
| 207 | (if (memq char '(?\177 ?\M-v)) |
| 208 | (scroll-down)) |
| 209 | (message "A B C F I K L M N S T V W C-c C-d C-n C-w%s: " |
| 210 | (if (pos-visible-in-window-p (point-max)) |
| 211 | "" " or Space to scroll")) |
| 212 | (let ((cursor-in-echo-area t)) |
| 213 | (setq char (read-char)))))) |
| 214 | (let ((defn (cdr (assq (downcase char) (cdr help-map))))) |
| 215 | (if defn (call-interactively defn) (ding))))) |
| 216 | |
| 217 | |
| 218 | (defun function-called-at-point () |
| 219 | (condition-case () |
| 220 | (save-excursion |
| 221 | (save-restriction |
| 222 | (narrow-to-region (max (point-min) (- (point) 1000)) (point-max)) |
| 223 | (backward-up-list 1) |
| 224 | (forward-char 1) |
| 225 | (let (obj) |
| 226 | (setq obj (read (current-buffer))) |
| 227 | (and (symbolp obj) (fboundp obj) obj)))) |
| 228 | (error nil))) |
| 229 | |
| 230 | (defun describe-function (function) |
| 231 | "Display the full documentation of FUNCTION (a symbol)." |
| 232 | (interactive |
| 233 | (let ((fn (function-called-at-point)) |
| 234 | (enable-recursive-minibuffers t) |
| 235 | val) |
| 236 | (setq val (completing-read (if fn |
| 237 | (format "Describe function (default %s): " fn) |
| 238 | "Describe function: ") |
| 239 | obarray 'fboundp t)) |
| 240 | (list (if (equal val "") |
| 241 | fn (intern val))))) |
| 242 | (with-output-to-temp-buffer "*Help*" |
| 243 | (prin1 function) |
| 244 | (princ ": |
| 245 | ") |
| 246 | (if (documentation function) |
| 247 | (princ (documentation function)) |
| 248 | (princ "not documented")) |
| 249 | (print-help-return-message))) |
| 250 | |
| 251 | (defun variable-at-point () |
| 252 | (condition-case () |
| 253 | (save-excursion |
| 254 | (forward-sexp -1) |
| 255 | (skip-chars-forward "'") |
| 256 | (let ((obj (read (current-buffer)))) |
| 257 | (and (symbolp obj) (boundp obj) obj))) |
| 258 | (error nil))) |
| 259 | |
| 260 | (defun describe-variable (variable) |
| 261 | "Display the full documentation of VARIABLE (a symbol)." |
| 262 | (interactive |
| 263 | (let ((v (variable-at-point)) |
| 264 | (enable-recursive-minibuffers t) |
| 265 | val) |
| 266 | (setq val (completing-read (if v |
| 267 | (format "Describe variable (default %s): " v) |
| 268 | "Describe variable: ") |
| 269 | obarray 'boundp t)) |
| 270 | (list (if (equal val "") |
| 271 | v (intern val))))) |
| 272 | (with-output-to-temp-buffer "*Help*" |
| 273 | (prin1 variable) |
| 274 | (princ "'s value is ") |
| 275 | (if (not (boundp variable)) |
| 276 | (princ "void.") |
| 277 | (prin1 (symbol-value variable))) |
| 278 | (terpri) (terpri) |
| 279 | (princ "Documentation:") |
| 280 | (terpri) |
| 281 | (let ((doc (documentation-property variable 'variable-documentation))) |
| 282 | (if doc |
| 283 | (princ (substitute-command-keys doc)) |
| 284 | (princ "not documented as a variable."))) |
| 285 | (print-help-return-message))) |
| 286 | |
| 287 | (defun command-apropos (string) |
| 288 | "Like apropos but lists only symbols that are names of commands |
| 289 | \(interactively callable functions)." |
| 290 | (interactive "sCommand apropos (regexp): ") |
| 291 | (let ((message |
| 292 | (let ((standard-output (get-buffer-create "*Help*"))) |
| 293 | (print-help-return-message 'identity)))) |
| 294 | (apropos string 'commandp) |
| 295 | (and message (message message)))) |