mirror of
https://git.savannah.gnu.org/git/emacs.git
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1125 lines
41 KiB
EmacsLisp
1125 lines
41 KiB
EmacsLisp
;;; help.el --- help commands for Emacs
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;; Copyright (C) 1985, 1986, 1993, 1994, 1998 Free Software Foundation, Inc.
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;; Maintainer: FSF
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;; Keywords: help, internal
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;; This file is part of GNU Emacs.
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;; GNU Emacs is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation; either version 2, or (at your option)
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;; any later version.
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;; GNU Emacs is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with GNU Emacs; see the file COPYING. If not, write to the
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;; Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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;; Boston, MA 02111-1307, USA.
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;;; Commentary:
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;; This code implements GNU Emacs' on-line help system, the one invoked by
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;;`M-x help-for-help'.
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;;; Code:
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;; Get the macro make-help-screen when this is compiled,
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;; or run interpreted, but not when the compiled code is loaded.
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(eval-when-compile (require 'help-macro))
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(defvar help-map (make-sparse-keymap)
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"Keymap for characters following the Help key.")
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(defvar help-mode-map (make-sparse-keymap)
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"Keymap for help mode.")
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(define-key global-map (char-to-string help-char) 'help-command)
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(define-key global-map [help] 'help-command)
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(define-key global-map [f1] 'help-command)
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(fset 'help-command help-map)
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(define-key help-map (char-to-string help-char) 'help-for-help)
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(define-key help-map [help] 'help-for-help)
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(define-key help-map [f1] 'help-for-help)
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(define-key help-map "?" 'help-for-help)
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(define-key help-map "\C-c" 'describe-copying)
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(define-key help-map "\C-d" 'describe-distribution)
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(define-key help-map "\C-w" 'describe-no-warranty)
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(define-key help-map "\C-p" 'describe-project)
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(define-key help-map "a" 'apropos-command)
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(define-key help-map "b" 'describe-bindings)
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(define-key help-map "c" 'describe-key-briefly)
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(define-key help-map "k" 'describe-key)
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(define-key help-map "d" 'describe-function)
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(define-key help-map "f" 'describe-function)
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(define-key help-map "F" 'view-emacs-FAQ)
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(define-key help-map "i" 'info)
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(define-key help-map "4i" 'info-other-window)
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(define-key help-map "\C-f" 'Info-goto-emacs-command-node)
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(define-key help-map "\C-k" 'Info-goto-emacs-key-command-node)
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(define-key help-map "\C-i" 'info-lookup-symbol)
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(define-key help-map "l" 'view-lossage)
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(define-key help-map "m" 'describe-mode)
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(define-key help-map "\C-n" 'view-emacs-news)
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(define-key help-map "n" 'view-emacs-news)
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(define-key help-map "p" 'finder-by-keyword)
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(autoload 'finder-by-keyword "finder"
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"Find packages matching a given keyword." t)
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(define-key help-map "s" 'describe-syntax)
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(define-key help-map "t" 'help-with-tutorial)
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(define-key help-map "w" 'where-is)
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(define-key help-map "v" 'describe-variable)
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(define-key help-map "q" 'help-quit)
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(define-key help-mode-map [mouse-2] 'help-follow-mouse)
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(define-key help-mode-map "\C-c\C-b" 'help-go-back)
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(define-key help-mode-map "\C-c\C-c" 'help-follow)
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(define-key help-mode-map "\t" 'help-next-ref)
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(define-key help-mode-map [backtab] 'help-previous-ref)
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(define-key help-mode-map [(shift tab)] 'help-previous-ref)
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;; Documentation only, since we use minor-mode-overriding-map-alist.
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(define-key help-mode-map "\r" 'help-follow)
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;; Font-locking is incompatible with the new xref stuff.
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;(defvar help-font-lock-keywords
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; (eval-when-compile
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; (let ((name-char "[-+a-zA-Z0-9_*]") (sym-char "[-+a-zA-Z0-9_:*]"))
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; (list
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; ;;
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; ;; The symbol itself.
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; (list (concat "\\`\\(" name-char "+\\)\\(\\(:\\)\\|\\('\\)\\)")
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; '(1 (if (match-beginning 3)
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; font-lock-function-name-face
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; font-lock-variable-name-face)))
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; ;;
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; ;; Words inside `' which tend to be symbol names.
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; (list (concat "`\\(" sym-char sym-char "+\\)'")
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; 1 'font-lock-constant-face t)
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; ;;
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; ;; CLisp `:' keywords as references.
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; (list (concat "\\<:" sym-char "+\\>") 0 'font-lock-builtin-face t))))
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; "Default expressions to highlight in Help mode.")
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(defvar help-xref-stack nil
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"A stack of ways by which to return to help buffers after following xrefs.
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Used by `help-follow' and `help-xref-go-back'.
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An element looks like (POSITION FUNCTION ARGS...).
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To use the element, do (apply FUNCTION ARGS) then (goto-char POSITION).")
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(put 'help-xref-stack 'permanent-local t)
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(defvar help-xref-stack-item nil
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"An item for `help-follow' in this buffer to push onto `help-xref-stack'.
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The format is (FUNCTION ARGS...).")
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(put 'help-xref-stack-item 'permanent-local t)
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(setq-default help-xref-stack nil help-xref-stack-item nil)
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(defun help-mode ()
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"Major mode for viewing help text and navigating references in it.
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Entry to this mode runs the normal hook `help-mode-hook'.
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Commands:
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\\{help-mode-map}"
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(interactive)
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(kill-all-local-variables)
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(use-local-map help-mode-map)
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(setq mode-name "Help")
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(setq major-mode 'help-mode)
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(make-local-variable 'font-lock-defaults)
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(setq font-lock-defaults nil) ; font-lock would defeat xref
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(view-mode)
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(make-local-variable 'view-no-disable-on-exit)
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(setq view-no-disable-on-exit t)
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;; `help-make-xrefs' would be run here if not invoked from
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;; `help-mode-maybe'.
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(run-hooks 'help-mode-hook))
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(defun help-mode-maybe ()
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(if (eq major-mode 'fundamental-mode)
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(help-mode))
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(when (eq major-mode 'help-mode)
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;; View mode's read-only status of existing *Help* buffer is lost
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;; by with-output-to-temp-buffer.
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(toggle-read-only 1)
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(help-make-xrefs (current-buffer)))
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(setq view-return-to-alist
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(list (cons (selected-window) help-return-method))))
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(add-hook 'temp-buffer-show-hook 'help-mode-maybe)
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(defun help-quit ()
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(interactive)
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nil)
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(defun help-with-tutorial (&optional arg)
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"Select the Emacs learn-by-doing tutorial.
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If there is a tutorial version written in the language
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of the selected language environment, that version is used.
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If there's no tutorial in that language, `TUTORIAL' is selected.
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With arg, you are asked to choose which language."
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(interactive "P")
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(let ((lang (if arg
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(read-language-name 'tutorial "Language: " "English")
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(if (get-language-info current-language-environment 'tutorial)
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current-language-environment
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"English")))
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file filename)
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(setq filename (get-language-info lang 'tutorial))
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(setq file (expand-file-name (concat "~/" filename)))
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(delete-other-windows)
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(if (get-file-buffer file)
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(switch-to-buffer (get-file-buffer file))
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(switch-to-buffer (create-file-buffer file))
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(setq buffer-file-name file)
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(setq default-directory (expand-file-name "~/"))
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(setq buffer-auto-save-file-name nil)
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(insert-file-contents (expand-file-name filename data-directory))
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(goto-char (point-min))
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(search-forward "\n<<")
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(beginning-of-line)
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(delete-region (point) (progn (end-of-line) (point)))
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(let ((n (- (window-height (selected-window))
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(count-lines (point-min) (point))
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6)))
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(if (< n 12)
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(newline n)
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;; Some people get confused by the large gap.
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(newline (/ n 2))
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(insert "[Middle of page left blank for didactic purposes. "
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"Text continues below]")
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(newline (- n (/ n 2)))))
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(goto-char (point-min))
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(set-buffer-modified-p nil))))
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(defun describe-key-briefly (key &optional insert)
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"Print the name of the function KEY invokes. KEY is a string.
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If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
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(interactive "kDescribe key briefly: \nP")
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(save-excursion
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(let ((modifiers (event-modifiers (aref key 0)))
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(standard-output (if insert (current-buffer) t))
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window position)
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;; For a mouse button event, go to the button it applies to
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;; to get the right key bindings. And go to the right place
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;; in case the keymap depends on where you clicked.
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(if (or (memq 'click modifiers) (memq 'down modifiers)
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(memq 'drag modifiers))
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(setq window (posn-window (event-start (aref key 0)))
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position (posn-point (event-start (aref key 0)))))
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(if (windowp window)
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(progn
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(set-buffer (window-buffer window))
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(goto-char position)))
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;; Ok, now look up the key and name the command.
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(let ((defn (key-binding key))
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(key-desc (key-description key)))
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(if (or (null defn) (integerp defn))
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(princ (format "%s is undefined" key-desc))
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(princ (format (if insert
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"`%s' (`%s')"
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(if (windowp window)
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"%s at that spot runs the command %s"
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"%s runs the command %s"))
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key-desc
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(if (symbolp defn) defn (prin1-to-string defn)))))))))
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(defvar help-return-method nil
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"What to do to \"exit\" the help buffer.
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This is a list
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(WINDOW . t) delete the selected window, go to WINDOW.
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(WINDOW . quit-window) do quit-window, then select WINDOW.
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(WINDOW BUF START POINT) display BUF at START, POINT, then select WINDOW.")
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(defun print-help-return-message (&optional function)
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"Display or return message saying how to restore windows after help command.
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Computes a message and applies the optional argument FUNCTION to it.
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If FUNCTION is nil, applies `message' to it, thus printing it."
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(and (not (get-buffer-window standard-output))
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(let ((first-message
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(cond ((special-display-p (buffer-name standard-output))
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(setq help-return-method (cons (selected-window) t))
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;; If the help output buffer is a special display buffer,
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;; don't say anything about how to get rid of it.
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;; First of all, the user will do that with the window
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;; manager, not with Emacs.
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;; Secondly, the buffer has not been displayed yet,
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;; so we don't know whether its frame will be selected.
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nil)
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((not (one-window-p t))
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(setq help-return-method
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(cons (selected-window) 'quit-window))
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"Type \\[switch-to-buffer-other-window] RET to restore the other window.")
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(pop-up-windows
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(setq help-return-method (cons (selected-window) t))
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"Type \\[delete-other-windows] to remove help window.")
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(t
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(setq help-return-method
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(list (selected-window) (window-buffer)
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(window-start) (window-point)))
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"Type \\[switch-to-buffer] RET to remove help window."))))
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(funcall (or function 'message)
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(concat
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(if first-message
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(substitute-command-keys first-message)
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"")
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(if first-message " " "")
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;; If the help buffer will go in a separate frame,
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;; it's no use mentioning a command to scroll, so don't.
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(if (special-display-p (buffer-name standard-output))
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nil
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(if (same-window-p (buffer-name standard-output))
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;; Say how to scroll this window.
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(substitute-command-keys
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"\\[scroll-up] to scroll the help.")
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;; Say how to scroll some other window.
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(substitute-command-keys
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"\\[scroll-other-window] to scroll the help."))))))))
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(defun describe-key (key)
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"Display documentation of the function invoked by KEY. KEY is a string."
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(interactive "kDescribe key: ")
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(save-excursion
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(let ((modifiers (event-modifiers (aref key 0)))
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window position)
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;; For a mouse button event, go to the button it applies to
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;; to get the right key bindings. And go to the right place
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;; in case the keymap depends on where you clicked.
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(if (or (memq 'click modifiers) (memq 'down modifiers)
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(memq 'drag modifiers))
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(setq window (posn-window (event-start (aref key 0)))
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position (posn-point (event-start (aref key 0)))))
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(if (windowp window)
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(progn
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(set-buffer (window-buffer window))
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(goto-char position)))
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(let ((defn (key-binding key)))
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(if (or (null defn) (integerp defn))
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(message "%s is undefined" (key-description key))
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(with-output-to-temp-buffer "*Help*"
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(princ (key-description key))
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(if (windowp window)
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(princ " at that spot"))
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(princ " runs the command ")
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(prin1 defn)
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(princ "\n which is ")
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(describe-function-1 defn nil)
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(print-help-return-message)))))))
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(defun describe-mode ()
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"Display documentation of current major mode and minor modes.
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For this to work correctly for a minor mode, the mode's indicator variable
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\(listed in `minor-mode-alist') must also be a function whose documentation
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describes the minor mode."
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(interactive)
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(with-output-to-temp-buffer "*Help*"
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(let ((minor-modes minor-mode-alist)
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(first t))
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(while minor-modes
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(let* ((minor-mode (car (car minor-modes)))
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(indicator (car (cdr (car minor-modes)))))
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;; Document a minor mode if it is listed in minor-mode-alist,
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;; bound locally in this buffer, non-nil, and has a function
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;; definition.
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(if (and (symbol-value minor-mode)
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(fboundp minor-mode))
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(let ((pretty-minor-mode minor-mode))
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(if (string-match "-mode$" (symbol-name minor-mode))
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(setq pretty-minor-mode
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(capitalize
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(substring (symbol-name minor-mode)
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0 (match-beginning 0)))))
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(while (and indicator (symbolp indicator))
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(setq indicator (symbol-value indicator)))
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(if first
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(princ "The minor modes are described first,
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followed by the major mode, which is described on the last page.\n\f\n"))
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(setq first nil)
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(princ (format "%s minor mode (%s):\n"
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pretty-minor-mode
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(if indicator
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(format "indicator%s" indicator)
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"no indicator")))
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(princ (documentation minor-mode))
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(princ "\n\f\n"))))
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(setq minor-modes (cdr minor-modes))))
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(princ mode-name)
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(princ " mode:\n")
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(princ (documentation major-mode))
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(help-setup-xref (list #'help-xref-mode (current-buffer)) (interactive-p))
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(print-help-return-message)))
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;; So keyboard macro definitions are documented correctly
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(fset 'defining-kbd-macro (symbol-function 'start-kbd-macro))
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(defun describe-distribution ()
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"Display info on how to obtain the latest version of GNU Emacs."
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(interactive)
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(find-file-read-only
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(expand-file-name "DISTRIB" data-directory)))
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(defun describe-copying ()
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"Display info on how you may redistribute copies of GNU Emacs."
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(interactive)
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(find-file-read-only
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(expand-file-name "COPYING" data-directory))
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(goto-char (point-min)))
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(defun describe-project ()
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"Display info on the GNU project."
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(interactive)
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(find-file-read-only
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(expand-file-name "GNU" data-directory))
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(goto-char (point-min)))
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(defun describe-no-warranty ()
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"Display info on all the kinds of warranty Emacs does NOT have."
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(interactive)
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(describe-copying)
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(let (case-fold-search)
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(search-forward "NO WARRANTY")
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(recenter 0)))
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(defun describe-prefix-bindings ()
|
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"Describe the bindings of the prefix used to reach this command.
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The prefix described consists of all but the last event
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of the key sequence that ran this command."
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(interactive)
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(let* ((key (this-command-keys)))
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(describe-bindings
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(if (stringp key)
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(substring key 0 (1- (length key)))
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(let ((prefix (make-vector (1- (length key)) nil))
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(i 0))
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(while (< i (length prefix))
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(aset prefix i (aref key i))
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(setq i (1+ i)))
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prefix)))))
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;; Make C-h after a prefix, when not specifically bound,
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;; run describe-prefix-bindings.
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(setq prefix-help-command 'describe-prefix-bindings)
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(defun view-emacs-news (&optional arg)
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"Display info on recent changes to Emacs.
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With numeric argument display information on correspondingly older changes."
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(interactive "P")
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(let* ((arg (if arg (prefix-numeric-value arg) 0)))
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(find-file-read-only
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(expand-file-name (concat (make-string arg ?O) "NEWS")
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data-directory))))
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|
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(defun view-emacs-FAQ ()
|
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"Display the Emacs Frequently Asked Questions (FAQ) file."
|
||
(interactive)
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||
(find-file-read-only (expand-file-name "FAQ" data-directory)))
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||
|
||
(defun view-lossage ()
|
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"Display last 100 input keystrokes."
|
||
(interactive)
|
||
(with-output-to-temp-buffer "*Help*"
|
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(princ (mapconcat (function (lambda (key)
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(if (or (integerp key)
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(symbolp key)
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(listp key))
|
||
(single-key-description key)
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(prin1-to-string key nil))))
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||
(recent-keys)
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||
" "))
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||
(save-excursion
|
||
(set-buffer standard-output)
|
||
(goto-char (point-min))
|
||
(while (progn (move-to-column 50) (not (eobp)))
|
||
(search-forward " " nil t)
|
||
(insert "\n"))
|
||
(setq help-xref-stack nil
|
||
help-xref-stack-item nil))
|
||
(print-help-return-message)))
|
||
|
||
(defalias 'help 'help-for-help)
|
||
(make-help-screen help-for-help
|
||
"a b c C f F C-f i I k C-k l L m n p s t v w C-c C-d C-n C-p C-w; ? for help:"
|
||
"You have typed \\[help-command], the help character. Type a Help option:
|
||
\(Use SPC or DEL to scroll through this text. Type \\<help-map>\\[help-quit] to exit the Help command.)
|
||
|
||
a command-apropos. Give a substring, and see a list of commands
|
||
(functions interactively callable) that contain
|
||
that substring. See also the apropos command.
|
||
b describe-bindings. Display table of all key bindings.
|
||
c describe-key-briefly. Type a command key sequence;
|
||
it prints the function name that sequence runs.
|
||
C describe-coding-system. This describes either a specific coding system
|
||
(if you type its name) or the coding systems currently in use
|
||
(if you type just RET).
|
||
f describe-function. Type a function name and get documentation of it.
|
||
C-f Info-goto-emacs-command-node. Type a function name;
|
||
it takes you to the Info node for that command.
|
||
i info. The info documentation reader.
|
||
I describe-input-method. Describe a specific input method (if you type
|
||
its name) or the current input method (if you type just RET).
|
||
k describe-key. Type a command key sequence;
|
||
it displays the full documentation.
|
||
C-k Info-goto-emacs-key-command-node. Type a command key sequence;
|
||
it takes you to the Info node for the command bound to that key.
|
||
l view-lossage. Shows last 100 characters you typed.
|
||
L describe-language-environment. This describes either the a
|
||
specific language environment (if you type its name)
|
||
or the current language environment (if you type just RET).
|
||
m describe-mode. Print documentation of current minor modes,
|
||
and the current major mode, including their special commands.
|
||
n view-emacs-news. Shows emacs news file.
|
||
p finder-by-keyword. Find packages matching a given topic keyword.
|
||
s describe-syntax. Display contents of syntax table, plus explanations
|
||
t help-with-tutorial. Select the Emacs learn-by-doing tutorial.
|
||
v describe-variable. Type name of a variable;
|
||
it displays the variable's documentation and value.
|
||
w where-is. Type command name; it prints which keystrokes
|
||
invoke that command.
|
||
|
||
F Display the frequently asked questions file.
|
||
h Display the HELLO file which illustrates various scripts.
|
||
C-c Display Emacs copying permission (General Public License).
|
||
C-d Display Emacs ordering information.
|
||
C-n Display news of recent Emacs changes.
|
||
C-p Display information about the GNU project.
|
||
C-w Display information on absence of warranty for GNU Emacs."
|
||
help-map)
|
||
|
||
;; Return a function which is called by the list containing point.
|
||
;; If that gives no function, return a function whose name is around point.
|
||
;; If that doesn't give a function, return nil.
|
||
(defun function-called-at-point ()
|
||
(let ((stab (syntax-table)))
|
||
(set-syntax-table emacs-lisp-mode-syntax-table)
|
||
(unwind-protect
|
||
(or (condition-case ()
|
||
(save-excursion
|
||
(save-restriction
|
||
(narrow-to-region (max (point-min) (- (point) 1000)) (point-max))
|
||
;; Move up to surrounding paren, then after the open.
|
||
(backward-up-list 1)
|
||
(forward-char 1)
|
||
;; If there is space here, this is probably something
|
||
;; other than a real Lisp function call, so ignore it.
|
||
(if (looking-at "[ \t]")
|
||
(error "Probably not a Lisp function call"))
|
||
(let (obj)
|
||
(setq obj (read (current-buffer)))
|
||
(and (symbolp obj) (fboundp obj) obj))))
|
||
(error nil))
|
||
(condition-case ()
|
||
(save-excursion
|
||
(or (not (zerop (skip-syntax-backward "_w")))
|
||
(eq (char-syntax (following-char)) ?w)
|
||
(eq (char-syntax (following-char)) ?_)
|
||
(forward-sexp -1))
|
||
(skip-chars-forward "'")
|
||
(let ((obj (read (current-buffer))))
|
||
(and (symbolp obj) (fboundp obj) obj)))
|
||
(error nil)))
|
||
(set-syntax-table stab))))
|
||
|
||
(defun describe-function-find-file (function)
|
||
(let ((files load-history)
|
||
file functions)
|
||
(while files
|
||
(if (memq function (cdr (car files)))
|
||
(setq file (car (car files)) files nil))
|
||
(setq files (cdr files)))
|
||
file))
|
||
|
||
(defun describe-function (function)
|
||
"Display the full documentation of FUNCTION (a symbol)."
|
||
(interactive
|
||
(let ((fn (function-called-at-point))
|
||
(enable-recursive-minibuffers t)
|
||
val)
|
||
(setq val (completing-read (if fn
|
||
(format "Describe function (default %s): " fn)
|
||
"Describe function: ")
|
||
obarray 'fboundp t nil nil (symbol-name fn)))
|
||
(list (if (equal val "")
|
||
fn (intern val)))))
|
||
(if function
|
||
(with-output-to-temp-buffer "*Help*"
|
||
(prin1 function)
|
||
;; Use " is " instead of a colon so that
|
||
;; it is easier to get out the function name using forward-sexp.
|
||
(princ " is ")
|
||
(describe-function-1 function nil)
|
||
(print-help-return-message)
|
||
(save-excursion
|
||
(set-buffer standard-output)
|
||
;; Return the text we displayed.
|
||
(buffer-string)))
|
||
(message "You didn't specify a function")))
|
||
|
||
(defun describe-function-1 (function parens)
|
||
(let* ((def (symbol-function function))
|
||
file-name string need-close
|
||
(beg (if (commandp def) "an interactive " "a ")))
|
||
(setq string
|
||
(cond ((or (stringp def)
|
||
(vectorp def))
|
||
"a keyboard macro")
|
||
((subrp def)
|
||
(concat beg "built-in function"))
|
||
((byte-code-function-p def)
|
||
(concat beg "compiled Lisp function"))
|
||
((symbolp def)
|
||
(while (symbolp (symbol-function def))
|
||
(setq def (symbol-function def)))
|
||
(format "alias for `%s'" def))
|
||
((eq (car-safe def) 'lambda)
|
||
(concat beg "Lisp function"))
|
||
((eq (car-safe def) 'macro)
|
||
"a Lisp macro")
|
||
((eq (car-safe def) 'mocklisp)
|
||
"a mocklisp function")
|
||
((eq (car-safe def) 'autoload)
|
||
(setq file-name (nth 1 def))
|
||
(format "%s autoloaded Lisp %s"
|
||
(if (commandp def) "an interactive" "an")
|
||
(if (nth 4 def) "macro" "function")
|
||
))
|
||
(t "")))
|
||
(when (and parens (not (equal string "")))
|
||
(setq need-close t)
|
||
(princ "("))
|
||
(princ string)
|
||
(or file-name
|
||
(setq file-name (describe-function-find-file function)))
|
||
(if file-name
|
||
(progn
|
||
(princ " in `")
|
||
;; We used to add .el to the file name,
|
||
;; but that's completely wrong when the user used load-file.
|
||
(princ file-name)
|
||
(princ "'")
|
||
;; Make a hyperlink to the library.
|
||
(with-current-buffer "*Help*"
|
||
(save-excursion
|
||
(re-search-backward "`\\([^`']+\\)'" nil t)
|
||
(help-xref-button 1 #'(lambda (arg)
|
||
(let ((location
|
||
(find-function-noselect arg)))
|
||
(pop-to-buffer (car location))
|
||
(goto-char (cdr location))))
|
||
function)))))
|
||
(if need-close (princ ")"))
|
||
(princ ".")
|
||
(terpri)
|
||
;; Handle symbols aliased to other symbols.
|
||
(setq def (indirect-function def))
|
||
;; If definition is a macro, find the function inside it.
|
||
(if (eq (car-safe def) 'macro)
|
||
(setq def (cdr def)))
|
||
(let ((arglist (cond ((byte-code-function-p def)
|
||
(car (append def nil)))
|
||
((eq (car-safe def) 'lambda)
|
||
(nth 1 def))
|
||
(t t))))
|
||
(if (listp arglist)
|
||
(progn
|
||
(princ (cons function
|
||
(mapcar (lambda (arg)
|
||
(if (memq arg '(&optional &rest))
|
||
arg
|
||
(intern (upcase (symbol-name arg)))))
|
||
arglist)))
|
||
(terpri))))
|
||
(let ((doc (documentation function)))
|
||
(if doc
|
||
(progn (terpri)
|
||
(princ doc)
|
||
(help-setup-xref (list #'describe-function function) (interactive-p)))
|
||
(princ "not documented")))))
|
||
|
||
;; We return 0 if we can't find a variable to return.
|
||
(defun variable-at-point ()
|
||
(condition-case ()
|
||
(let ((stab (syntax-table)))
|
||
(unwind-protect
|
||
(save-excursion
|
||
(set-syntax-table emacs-lisp-mode-syntax-table)
|
||
(or (not (zerop (skip-syntax-backward "_w")))
|
||
(eq (char-syntax (following-char)) ?w)
|
||
(eq (char-syntax (following-char)) ?_)
|
||
(forward-sexp -1))
|
||
(skip-chars-forward "'")
|
||
(let ((obj (read (current-buffer))))
|
||
(or (and (symbolp obj) (boundp obj) obj)
|
||
0)))
|
||
(set-syntax-table stab)))
|
||
(error 0)))
|
||
|
||
(defun describe-variable (variable)
|
||
"Display the full documentation of VARIABLE (a symbol).
|
||
Returns the documentation as a string, also."
|
||
(interactive
|
||
(let ((v (variable-at-point))
|
||
(enable-recursive-minibuffers t)
|
||
val)
|
||
(setq val (completing-read (if (symbolp v)
|
||
(format "Describe variable (default %s): " v)
|
||
"Describe variable: ")
|
||
obarray 'boundp t nil nil
|
||
(if (symbolp v) (symbol-name v))))
|
||
(list (if (equal val "")
|
||
v (intern val)))))
|
||
(if (symbolp variable)
|
||
(let (valvoid)
|
||
(with-output-to-temp-buffer "*Help*"
|
||
(prin1 variable)
|
||
(if (not (boundp variable))
|
||
(progn
|
||
(princ " is void")
|
||
(terpri)
|
||
(setq valvoid t))
|
||
(princ "'s value is ")
|
||
(terpri)
|
||
(pp (symbol-value variable))
|
||
(terpri))
|
||
(if (local-variable-p variable)
|
||
(progn
|
||
(princ (format "Local in buffer %s; " (buffer-name)))
|
||
(if (not (default-boundp variable))
|
||
(princ "globally void")
|
||
(princ "global value is ")
|
||
(terpri)
|
||
(pp (default-value variable)))
|
||
(terpri)))
|
||
(terpri)
|
||
(save-current-buffer
|
||
(set-buffer standard-output)
|
||
(if (> (count-lines (point-min) (point-max)) 10)
|
||
(progn
|
||
(goto-char (point-min))
|
||
(if valvoid
|
||
(forward-line 1)
|
||
(forward-sexp 1)
|
||
(delete-region (point) (progn (end-of-line) (point)))
|
||
(insert "'s value is shown below.\n\n")
|
||
(save-excursion
|
||
(insert "\n\nValue:"))))))
|
||
(princ "Documentation:")
|
||
(terpri)
|
||
(let ((doc (documentation-property variable 'variable-documentation)))
|
||
(princ (or doc "not documented as a variable.")))
|
||
(help-setup-xref (list #'describe-variable variable) (interactive-p))
|
||
|
||
;; Make a link to customize if this variable can be customized.
|
||
;; Note, it is not reliable to test for a custom-type property
|
||
;; because those are only present after the var's definition
|
||
;; has been loaded.
|
||
(if (user-variable-p variable)
|
||
(let ((customize-label "customize"))
|
||
(terpri)
|
||
(terpri)
|
||
(princ (concat "You can " customize-label " this variable."))
|
||
(with-current-buffer "*Help*"
|
||
(save-excursion
|
||
(re-search-backward
|
||
(concat "\\(" customize-label "\\)") nil t)
|
||
(help-xref-button 1 #'(lambda (v)
|
||
(customize-variable v)) variable)
|
||
))))
|
||
|
||
(print-help-return-message)
|
||
(save-excursion
|
||
(set-buffer standard-output)
|
||
;; Return the text we displayed.
|
||
(buffer-string))))
|
||
(message "You did not specify a variable")))
|
||
|
||
(defun describe-bindings (&optional prefix buffer)
|
||
"Show a list of all defined keys, and their definitions.
|
||
We put that list in a buffer, and display the buffer.
|
||
|
||
The optional argument PREFIX, if non-nil, should be a key sequence;
|
||
then we display only bindings that start with that prefix.
|
||
The optional argument BUFFER specifies which buffer's bindings
|
||
to display (default, the current buffer)."
|
||
(interactive "P")
|
||
(or buffer (setq buffer (current-buffer)))
|
||
(with-current-buffer buffer
|
||
(describe-bindings-internal nil prefix))
|
||
(with-current-buffer "*Help*"
|
||
(help-setup-xref (list #'describe-bindings prefix buffer)
|
||
(interactive-p))))
|
||
|
||
(defun where-is (definition &optional insert)
|
||
"Print message listing key sequences that invoke specified command.
|
||
Argument is a command definition, usually a symbol with a function definition.
|
||
If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
|
||
(interactive
|
||
(let ((fn (function-called-at-point))
|
||
(enable-recursive-minibuffers t)
|
||
val)
|
||
(setq val (completing-read (if fn
|
||
(format "Where is command (default %s): " fn)
|
||
"Where is command: ")
|
||
obarray 'fboundp t))
|
||
(list (if (equal val "")
|
||
fn (intern val))
|
||
current-prefix-arg)))
|
||
(let* ((keys (where-is-internal definition overriding-local-map nil nil))
|
||
(keys1 (mapconcat 'key-description keys ", "))
|
||
(standard-output (if insert (current-buffer) t)))
|
||
(if insert
|
||
(if (> (length keys1) 0)
|
||
(princ (format "%s (%s)" keys1 definition))
|
||
(princ (format "M-x %s RET" definition)))
|
||
(if (> (length keys1) 0)
|
||
(princ (format "%s is on %s" definition keys1))
|
||
(princ (format "%s is not on any key" definition)))))
|
||
nil)
|
||
|
||
(defun locate-library (library &optional nosuffix path interactive-call)
|
||
"Show the precise file name of Emacs library LIBRARY.
|
||
This command searches the directories in `load-path' like `M-x load-library'
|
||
to find the file that `M-x load-library RET LIBRARY RET' would load.
|
||
Optional second arg NOSUFFIX non-nil means don't add suffixes `.elc' or `.el'
|
||
to the specified name LIBRARY.
|
||
|
||
If the optional third arg PATH is specified, that list of directories
|
||
is used instead of `load-path'."
|
||
(interactive (list (read-string "Locate library: ")
|
||
nil nil
|
||
t))
|
||
(let (result)
|
||
(catch 'answer
|
||
(mapcar
|
||
(lambda (dir)
|
||
(mapcar
|
||
(lambda (suf)
|
||
(let ((try (expand-file-name (concat library suf) dir)))
|
||
(and (file-readable-p try)
|
||
(null (file-directory-p try))
|
||
(progn
|
||
(setq result try)
|
||
(throw 'answer try)))))
|
||
(if nosuffix
|
||
'("")
|
||
'(".elc" ".el" "")
|
||
;;; load doesn't handle this yet.
|
||
;;; (let ((basic '(".elc" ".el" ""))
|
||
;;; (compressed '(".Z" ".gz" "")))
|
||
;;; ;; If autocompression mode is on,
|
||
;;; ;; consider all combinations of library suffixes
|
||
;;; ;; and compression suffixes.
|
||
;;; (if (rassq 'jka-compr-handler file-name-handler-alist)
|
||
;;; (apply 'nconc
|
||
;;; (mapcar (lambda (compelt)
|
||
;;; (mapcar (lambda (baselt)
|
||
;;; (concat baselt compelt))
|
||
;;; basic))
|
||
;;; compressed))
|
||
;;; basic))
|
||
)))
|
||
(or path load-path)))
|
||
(and interactive-call
|
||
(if result
|
||
(message "Library is file %s" result)
|
||
(message "No library %s in search path" library)))
|
||
result))
|
||
|
||
|
||
;;; Grokking cross-reference information in doc strings and
|
||
;;; hyperlinking it.
|
||
|
||
;; This may have some scope for extension and the same or something
|
||
;; similar should be done for widget doc strings, which currently use
|
||
;; another mechanism.
|
||
|
||
(defcustom help-highlight-p t
|
||
"*If non-nil, `help-make-xrefs' highlight cross-references.
|
||
Under a window system it highlights them with face defined by
|
||
`help-highlight-face'. On a character terminal highlighted
|
||
references look like cross-references in info mode."
|
||
:group 'help
|
||
:version "20.3"
|
||
:type 'boolean)
|
||
|
||
(defcustom help-highlight-face 'underline
|
||
"Face used by `help-make-xrefs' to highlight cross-references.
|
||
Must be previously-defined."
|
||
:group 'help
|
||
:version "20.3"
|
||
:type 'face)
|
||
|
||
(defvar help-back-label "[back]"
|
||
"Label to use by `help-make-xrefs' for the go-back reference.")
|
||
|
||
(defvar help-xref-symbol-regexp
|
||
(concat "\\(\\<\\(\\(variable\\|option\\)\\|"
|
||
"\\(function\\|command\\)\\|"
|
||
"\\(symbol\\)\\)\\s-+\\)?"
|
||
;; Note starting with word-syntax character:
|
||
"`\\(\\sw\\(\\sw\\|\\s_\\)+\\)'")
|
||
"Regexp matching doc string references to symbols.
|
||
|
||
The words preceding the quoted symbol can be used in doc strings to
|
||
distinguish references to variables, functions and symbols.")
|
||
|
||
(defvar help-xref-info-regexp
|
||
"\\<info\\s-+node\\s-`\\([^']+\\)'"
|
||
"Regexp matching doc string references to an Info node.")
|
||
|
||
(defun help-setup-xref (item interactive-p)
|
||
"Invoked from commands using the \"*Help*\" buffer to install some xref info.
|
||
|
||
ITEM is a (FUNCTION . ARGS) pair appropriate for recreating the help
|
||
buffer after following a reference. INTERACTIVE-P is non-nil if the
|
||
calling command was invoked interactively. In this case the stack of
|
||
items for help buffer \"back\" buttons is cleared."
|
||
(if interactive-p
|
||
(setq help-xref-stack nil))
|
||
(setq help-xref-stack-item item))
|
||
|
||
(defun help-make-xrefs (&optional buffer)
|
||
"Parse and hyperlink documentation cross-references in the given BUFFER.
|
||
|
||
Find cross-reference information in a buffer and, if
|
||
`help-highlight-p' is non-nil, highlight it with face defined by
|
||
`help-highlight-face'; activate such cross references for selection
|
||
with `help-follow'. Cross-references have the canonical form `...'
|
||
and the type of reference may be disambiguated by the preceding
|
||
word(s) used in `help-xref-symbol-regexp'.
|
||
|
||
A special reference `back' is made to return back through a stack of
|
||
help buffers. Variable `help-back-label' specifies the text for
|
||
that."
|
||
(interactive "b")
|
||
(save-excursion
|
||
(set-buffer (or buffer (current-buffer)))
|
||
(goto-char (point-min))
|
||
;; Skip the header-type info, though it might be useful to parse
|
||
;; it at some stage (e.g. "function in `library'").
|
||
(forward-paragraph)
|
||
(let ((old-modified (buffer-modified-p)))
|
||
(let ((stab (syntax-table))
|
||
(case-fold-search t)
|
||
(inhibit-read-only t))
|
||
(set-syntax-table emacs-lisp-mode-syntax-table)
|
||
;; The following should probably be abstracted out.
|
||
(unwind-protect
|
||
(progn
|
||
;; Quoted symbols
|
||
(save-excursion
|
||
(while (re-search-forward help-xref-symbol-regexp nil t)
|
||
(let* ((data (match-string 6))
|
||
(sym (intern-soft data)))
|
||
(if sym
|
||
(cond
|
||
((match-string 3) ; `variable' &c
|
||
(and (boundp sym) ; `variable' doesn't ensure
|
||
; it's actually bound
|
||
(help-xref-button 6 #'describe-variable sym)))
|
||
((match-string 4) ; `function' &c
|
||
(and (fboundp sym) ; similarly
|
||
(help-xref-button 6 #'describe-function sym)))
|
||
((match-string 5)) ; nothing for symbol
|
||
((and (boundp sym) (fboundp sym))
|
||
;; We can't intuit whether to use the
|
||
;; variable or function doc -- supply both.
|
||
(help-xref-button 6 #'help-xref-interned sym))
|
||
((boundp sym)
|
||
(help-xref-button 6 #'describe-variable sym))
|
||
((fboundp sym)
|
||
(help-xref-button 6 #'describe-function sym)))))))
|
||
;; Info references
|
||
(save-excursion
|
||
(while (re-search-forward help-xref-info-regexp nil t)
|
||
(help-xref-button 1 #'Info-goto-node (list (match-data 1)))))
|
||
;; An obvious case of a key substitution:
|
||
(save-excursion
|
||
(while (re-search-forward
|
||
"\\<M-x\\s-+\\(\\sw\\(\\sw\\|\\s_\\)+\\)" nil t)
|
||
(let ((sym (intern-soft (match-string 1))))
|
||
(if (fboundp sym)
|
||
(help-xref-button 1 #'describe-function sym)))))
|
||
;; Look for commands in whole keymap substitutions:
|
||
(save-excursion
|
||
;; Make sure to find the first keymap.
|
||
(goto-char (point-min))
|
||
;; Find a header and the column at which the command
|
||
;; name will be found.
|
||
(while (re-search-forward "^key +binding\n\\(-+ +\\)-+\n\n"
|
||
nil t)
|
||
(let ((col (- (match-end 1) (match-beginning 1))))
|
||
(while
|
||
;; Ignore single blank lines in table, but not
|
||
;; double ones, which should terminate it.
|
||
(and (looking-at "^\n?[^\n]")
|
||
(progn
|
||
(if (and (> (move-to-column col) 0)
|
||
(looking-at "\\(\\sw\\|\\s_\\)+$"))
|
||
;;
|
||
(let ((sym (intern-soft (match-string 0))))
|
||
(if (fboundp sym)
|
||
(help-xref-button
|
||
0 #'describe-function sym))))
|
||
t)
|
||
(zerop (forward-line))
|
||
(move-to-column 0)))))))
|
||
(set-syntax-table stab))
|
||
;; Make a back-reference in this buffer if appropriate.
|
||
(when help-xref-stack
|
||
(goto-char (point-max))
|
||
(save-excursion
|
||
(insert "\n\n" help-back-label))
|
||
;; Just to provide the match data:
|
||
(looking-at (concat "\n\n\\(" (regexp-quote help-back-label) "\\)"))
|
||
(help-xref-button 1 #'help-xref-go-back (current-buffer))))
|
||
;; View mode steals RET from us.
|
||
(set (make-local-variable 'minor-mode-overriding-map-alist)
|
||
(list (cons 'view-mode
|
||
(let ((map (make-sparse-keymap)))
|
||
(set-keymap-parent map view-mode-map)
|
||
(define-key map "\r" 'help-follow)
|
||
map))))
|
||
(set-buffer-modified-p old-modified))))
|
||
|
||
(defun help-xref-button (match-number function data)
|
||
"Make a hyperlink for cross-reference text previously matched.
|
||
|
||
MATCH-NUMBER is the subexpression of interest in the last matched
|
||
regexp. FUNCTION is a function to invoke when the button is
|
||
activated, applied to DATA. DATA may be a single value or a list.
|
||
See `help-make-xrefs'."
|
||
(add-text-properties (match-beginning match-number)
|
||
(match-end match-number)
|
||
(list 'mouse-face 'highlight
|
||
'help-xref (cons function
|
||
(if (listp data)
|
||
data
|
||
(list data)))))
|
||
(if help-highlight-p
|
||
(put-text-property (match-beginning match-number)
|
||
(match-end match-number)
|
||
'face help-highlight-face)))
|
||
|
||
|
||
;; Additional functions for (re-)creating types of help buffers.
|
||
(defun help-xref-interned (symbol)
|
||
"Follow a hyperlink which appeared to be an arbitrary interned SYMBOL.
|
||
|
||
Both variable and function documentation are extracted into a single
|
||
help buffer."
|
||
(let ((fdoc (describe-function symbol)))
|
||
(describe-variable symbol)
|
||
;; We now have a help buffer on the variable. Insert the function
|
||
;; text after it.
|
||
(goto-char (point-max))
|
||
(insert "\n\n" fdoc))
|
||
(goto-char (point-min))
|
||
(help-setup-xref (list #'help-xref-interned symbol) nil))
|
||
|
||
(defun help-xref-mode (buffer)
|
||
"Do a `describe-mode' for the specified BUFFER."
|
||
(save-excursion
|
||
(set-buffer buffer)
|
||
(describe-mode)))
|
||
|
||
;;; Navigation/hyperlinking with xrefs
|
||
|
||
(defun help-follow-mouse (click)
|
||
"Follow the cross-reference that you click on."
|
||
(interactive "e")
|
||
(let* ((start (event-start click))
|
||
(window (car start))
|
||
(pos (car (cdr start))))
|
||
(with-current-buffer (window-buffer window)
|
||
(help-follow pos))))
|
||
|
||
(defun help-xref-go-back (buffer)
|
||
"Go back to the previous help buffer text using info on `help-xref-stack'."
|
||
(interactive)
|
||
(let (item position method args)
|
||
(with-current-buffer buffer
|
||
(when help-xref-stack
|
||
(setq help-xref-stack (cdr help-xref-stack)) ; due to help-follow
|
||
(setq item (car help-xref-stack)
|
||
position (car item)
|
||
method (cadr item)
|
||
args (cddr item))
|
||
(setq help-xref-stack (cdr help-xref-stack))))
|
||
(apply method args)
|
||
(goto-char position)))
|
||
|
||
(defun help-go-back ()
|
||
(interactive)
|
||
(help-follow (1- (point-max))))
|
||
|
||
(defun help-follow (&optional pos)
|
||
"Follow cross-reference at POS, defaulting to point.
|
||
|
||
For the cross-reference format, see `help-make-xrefs'."
|
||
(interactive "d")
|
||
(let* ((help-data (or (and (not (= pos (point-max)))
|
||
(get-text-property pos 'help-xref))
|
||
(and (not (= pos (point-min)))
|
||
(get-text-property (1- pos) 'help-xref))))
|
||
(method (car help-data))
|
||
(args (cdr help-data)))
|
||
(setq help-xref-stack (cons (cons (point) help-xref-stack-item)
|
||
help-xref-stack))
|
||
(setq help-xref-stack-item nil)
|
||
(when help-data
|
||
;; There is a reference at point. Follow it.
|
||
(apply method args))))
|
||
|
||
;; For tabbing through buffer.
|
||
(defun help-next-ref ()
|
||
"Find the next help cross-reference in the buffer."
|
||
(interactive)
|
||
(let (pos)
|
||
(while (not pos)
|
||
(if (get-text-property (point) 'help-xref) ; move off reference
|
||
(goto-char (or (next-single-property-change (point) 'help-xref)
|
||
(point))))
|
||
(cond ((setq pos (next-single-property-change (point) 'help-xref))
|
||
(if pos (goto-char pos)))
|
||
((bobp)
|
||
(message "No cross references in the buffer.")
|
||
(setq pos t))
|
||
(t ; be circular
|
||
(goto-char (point-min)))))))
|
||
|
||
(defun help-previous-ref ()
|
||
"Find the previous help cross-reference in the buffer."
|
||
(interactive)
|
||
(let (pos)
|
||
(while (not pos)
|
||
(if (get-text-property (point) 'help-xref) ; move off reference
|
||
(goto-char (or (previous-single-property-change (point) 'help-xref)
|
||
(point))))
|
||
(cond ((setq pos (previous-single-property-change (point) 'help-xref))
|
||
(if pos (goto-char pos)))
|
||
((bobp)
|
||
(message "No cross references in the buffer.")
|
||
(setq pos t))
|
||
(t ; be circular
|
||
(goto-char (point-max)))))))
|
||
|
||
;;; help.el ends here
|