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526 lines
18 KiB
EmacsLisp
526 lines
18 KiB
EmacsLisp
;;; help-fns.el --- Complex help functions
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;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999, 2000, 2001
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;; 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 file contains those help commands which are complicated, and
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;; which may not be used in every session. For example
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;; `describe-function' will probably be heavily used when doing elisp
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;; programming, but not if just editing C files. Simpler help commands
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;; are in help.el
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;;; Code:
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(require 'help-mode)
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;;;###autoload
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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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;; Convert the <<...>> line to the proper [...] line,
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;; or just delete the <<...>> line if a [...] line follows.
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(cond ((save-excursion
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(forward-line 1)
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(looking-at "\\["))
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(delete-region (point) (progn (forward-line 1) (point))))
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((looking-at "<<Blank lines inserted.*>>")
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(replace-match "[Middle of page left blank for didactic purposes. Text continues below]"))
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(t
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(looking-at "<<")
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(replace-match "[")
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(search-forward ">>")
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(replace-match "]")))
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(beginning-of-line)
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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 8)
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(progn
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;; For a short gap, we don't need the [...] line,
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;; so delete it.
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(delete-region (point) (progn (end-of-line) (point)))
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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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;; Skip the [...] line (don't delete it).
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(forward-line 1)
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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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;;;###autoload
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(defun locate-library (library &optional nosuffix path interactive-call)
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"Show the precise file name of Emacs library LIBRARY.
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This command searches the directories in `load-path' like `M-x load-library'
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to find the file that `M-x load-library RET LIBRARY RET' would load.
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Optional second arg NOSUFFIX non-nil means don't add suffixes `load-suffixes'
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to the specified name LIBRARY.
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If the optional third arg PATH is specified, that list of directories
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is used instead of `load-path'.
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When called from a program, the file name is normaly returned as a
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string. When run interactively, the argument INTERACTIVE-CALL is t,
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and the file name is displayed in the echo area."
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(interactive (list (read-string "Locate library: ")
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nil nil
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t))
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(catch 'answer
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(dolist (dir (or path load-path))
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(dolist (suf (append (unless nosuffix load-suffixes) '("")))
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(let ((try (expand-file-name (concat library suf) dir)))
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(and (file-readable-p try)
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(null (file-directory-p try))
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(progn
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(if interactive-call
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(message "Library is file %s" (abbreviate-file-name try)))
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(throw 'answer try))))))
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(if interactive-call
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(message "No library %s in search path" library))
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nil))
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;; Functions
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;;;###autoload
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(defun describe-function (function)
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"Display the full documentation of FUNCTION (a symbol)."
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(interactive
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(let ((fn (function-called-at-point))
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(enable-recursive-minibuffers t)
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val)
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(setq val (completing-read (if fn
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(format "Describe function (default %s): " fn)
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"Describe function: ")
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obarray 'fboundp t nil nil (symbol-name fn)))
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(list (if (equal val "")
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fn (intern val)))))
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(if (null function)
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(message "You didn't specify a function")
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(help-setup-xref (list #'describe-function function) (interactive-p))
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(save-excursion
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(with-output-to-temp-buffer (help-buffer)
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(prin1 function)
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;; Use " is " instead of a colon so that
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;; it is easier to get out the function name using forward-sexp.
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(princ " is ")
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(describe-function-1 function)
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(print-help-return-message)
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(with-current-buffer standard-output
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;; Return the text we displayed.
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(buffer-string))))))
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;;;###autoload
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(defun describe-function-1 (function)
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(let* ((def (if (symbolp function)
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(symbol-function function)
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function))
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file-name string
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(beg (if (commandp def) "an interactive " "a ")))
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(setq string
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(cond ((or (stringp def)
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(vectorp def))
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"a keyboard macro")
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((subrp def)
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(if (eq 'unevalled (cdr (subr-arity def)))
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(concat beg "special form")
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(concat beg "built-in function")))
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((byte-code-function-p def)
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(concat beg "compiled Lisp function"))
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((symbolp def)
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(while (symbolp (symbol-function def))
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(setq def (symbol-function def)))
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(format "an alias for `%s'" def))
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((eq (car-safe def) 'lambda)
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(concat beg "Lisp function"))
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((eq (car-safe def) 'macro)
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"a Lisp macro")
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((eq (car-safe def) 'autoload)
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(setq file-name (nth 1 def))
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(format "%s autoloaded %s"
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(if (commandp def) "an interactive" "an")
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(if (eq (nth 4 def) 'keymap) "keymap"
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(if (nth 4 def) "Lisp macro" "Lisp function"))
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))
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;; perhaps use keymapp here instead
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((eq (car-safe def) 'keymap)
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(let ((is-full nil)
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(elts (cdr-safe def)))
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(while elts
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(if (char-table-p (car-safe elts))
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(setq is-full t
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elts nil))
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(setq elts (cdr-safe elts)))
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(if is-full
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"a full keymap"
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"a sparse keymap")))
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(t "")))
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(princ string)
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(with-current-buffer standard-output
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(save-excursion
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(save-match-data
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(if (re-search-backward "alias for `\\([^`']+\\)'" nil t)
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(help-xref-button 1 'help-function def)))))
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(or file-name
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(setq file-name (symbol-file function)))
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(when (equal file-name "loaddefs.el")
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;; Find the real def site of the preloaded function.
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;; This is necessary only for defaliases.
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(let ((location
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(condition-case nil
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(find-function-search-for-symbol function nil "loaddefs.el")
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(error nil))))
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(when location
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(with-current-buffer (car location)
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(goto-char (cdr location))
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(when (re-search-backward
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"^;;; Generated autoloads from \\(.*\\)" nil t)
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(setq file-name (match-string 1)))))))
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(cond
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(file-name
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(princ " in `")
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;; We used to add .el to the file name,
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;; but that's completely wrong when the user used load-file.
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(princ file-name)
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(princ "'")
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;; Make a hyperlink to the library.
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(with-current-buffer standard-output
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(save-excursion
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(re-search-backward "`\\([^`']+\\)'" nil t)
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(help-xref-button 1 'help-function-def function file-name)))))
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(princ ".")
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(terpri)
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(when (commandp function)
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(let* ((remapped (remap-command function))
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(keys (where-is-internal
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(or remapped function) overriding-local-map nil nil)))
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(when remapped
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(princ "It is remapped to `")
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(princ (symbol-name remapped))
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(princ "'"))
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(when keys
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(princ (if remapped " which is bound to " "It is bound to "))
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;; FIXME: This list can be very long (f.ex. for self-insert-command).
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(princ (mapconcat 'key-description keys ", ")))
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(when (or remapped keys)
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(princ ".")
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(terpri))))
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;; Handle symbols aliased to other symbols.
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(setq def (indirect-function def))
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;; If definition is a macro, find the function inside it.
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(if (eq (car-safe def) 'macro)
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(setq def (cdr def)))
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(let ((arglist (cond ((byte-code-function-p def)
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(car (append def nil)))
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((eq (car-safe def) 'lambda)
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(nth 1 def))
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((and (eq (car-safe def) 'autoload)
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(not (eq (nth 4 def) 'keymap)))
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(concat "[Arg list not available until "
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"function definition is loaded.]"))
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(t t))))
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(cond ((listp arglist)
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(princ (cons (if (symbolp function) function "anonymous")
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(mapcar (lambda (arg)
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(if (memq arg '(&optional &rest))
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arg
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(intern (upcase (symbol-name arg)))))
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arglist)))
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(terpri))
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((stringp arglist)
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(princ arglist)
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(terpri))))
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(let ((doc (documentation function)))
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(if doc
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(progn (terpri)
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(princ doc)
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(if (subrp def)
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(with-current-buffer standard-output
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(beginning-of-line)
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;; Builtins get the calling sequence at the end of
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;; the doc string. Move it to the same place as
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;; for other functions.
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;; In cases where `function' has been fset to a
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;; subr we can't search for function's name in
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;; the doc string. Kluge round that using the
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;; printed representation. The arg list then
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;; shows the wrong function name, but that
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;; might be a useful hint.
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(let* ((rep (prin1-to-string def))
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(name (progn
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(string-match " \\([^ ]+\\)>$" rep)
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(match-string 1 rep))))
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(if (looking-at (format "(%s[ )]" (regexp-quote name)))
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(let ((start (point-marker)))
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(goto-char (point-min))
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(forward-paragraph)
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(insert-buffer-substring (current-buffer) start)
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(insert ?\n)
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(delete-region (1- start) (point-max)))
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(goto-char (point-min))
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(forward-paragraph)
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(insert
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"[Missing arglist. Please make a bug report.]\n")))
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(goto-char (point-max)))))
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(princ "not documented")))))
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;; Variables
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;;;###autoload
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(defun variable-at-point ()
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"Return the bound variable symbol found around point.
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Return 0 if there is no such symbol."
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(condition-case ()
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(with-syntax-table emacs-lisp-mode-syntax-table
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(save-excursion
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(or (not (zerop (skip-syntax-backward "_w")))
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(eq (char-syntax (following-char)) ?w)
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(eq (char-syntax (following-char)) ?_)
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(forward-sexp -1))
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(skip-chars-forward "'")
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(let ((obj (read (current-buffer))))
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(or (and (symbolp obj) (boundp obj) obj)
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0))))
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(error 0)))
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;;;###autoload
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(defun describe-variable (variable &optional buffer)
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"Display the full documentation of VARIABLE (a symbol).
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Returns the documentation as a string, also.
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If VARIABLE has a buffer-local value in BUFFER (default to the current buffer),
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it is displayed along with the global value."
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(interactive
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(let ((v (variable-at-point))
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(enable-recursive-minibuffers t)
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val)
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(setq val (completing-read (if (symbolp v)
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(format
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"Describe variable (default %s): " v)
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"Describe variable: ")
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obarray 'boundp t nil nil
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(if (symbolp v) (symbol-name v))))
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(list (if (equal val "")
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v (intern val)))))
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(unless (bufferp buffer) (setq buffer (current-buffer)))
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(if (not (symbolp variable))
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(message "You did not specify a variable")
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(save-excursion
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(let (valvoid)
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(help-setup-xref (list #'describe-variable variable buffer)
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(interactive-p))
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(with-output-to-temp-buffer (help-buffer)
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(with-current-buffer buffer
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(prin1 variable)
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(if (not (boundp variable))
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(progn
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(princ " is void")
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(setq valvoid t))
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(let ((val (symbol-value variable)))
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(with-current-buffer standard-output
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(princ "'s value is ")
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(terpri)
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(let ((from (point)))
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(pp val)
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(help-xref-on-pp from (point))
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(if (< (point) (+ from 20))
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(save-excursion
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(goto-char from)
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(delete-char -1)))))))
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(terpri)
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(when (local-variable-p variable)
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(princ (format "Local in buffer %s; " (buffer-name)))
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(if (not (default-boundp variable))
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(princ "globally void")
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(let ((val (default-value variable)))
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(with-current-buffer standard-output
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(princ "global value is ")
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(terpri)
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;; Fixme: pp can take an age if you happen to
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;; ask for a very large expression. We should
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;; probably print it raw once and check it's a
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;; sensible size before prettyprinting. -- fx
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(let ((from (point)))
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(pp val)
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(help-xref-on-pp from (point))
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(if (< (point) (+ from 20))
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(save-excursion
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(goto-char from)
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(delete-char -1)))))))
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(terpri))
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(terpri)
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(with-current-buffer standard-output
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(when (> (count-lines (point-min) (point-max)) 10)
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;; Note that setting the syntax table like below
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;; makes forward-sexp move over a `'s' at the end
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;; of a symbol.
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(set-syntax-table emacs-lisp-mode-syntax-table)
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(goto-char (point-min))
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(if valvoid
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(forward-line 1)
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(forward-sexp 1)
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(delete-region (point) (progn (end-of-line) (point)))
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(insert " value is shown below.\n\n")
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(save-excursion
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(insert "\n\nValue:"))))
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;; Add a note for variables that have been make-var-buffer-local.
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(when (and (local-variable-if-set-p variable)
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(or (not (local-variable-p variable))
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(with-temp-buffer
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(local-variable-if-set-p variable))))
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(save-excursion
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(forward-line -1)
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(insert "Automatically becomes buffer-local when set in any fashion.\n"))))
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(princ "Documentation:")
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(terpri)
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(let ((doc (documentation-property variable 'variable-documentation)))
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(princ (or doc "not documented as a variable.")))
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;; Make a link to customize if this variable can be customized.
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;; Note, it is not reliable to test only for a custom-type property
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;; because those are only present after the var's definition
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;; has been loaded.
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(if (or (get variable 'custom-type) ; after defcustom
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(get variable 'custom-loads) ; from loaddefs.el
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(get variable 'standard-value)) ; from cus-start.el
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(let ((customize-label "customize"))
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(terpri)
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(terpri)
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(princ (concat "You can " customize-label " this variable."))
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(with-current-buffer standard-output
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(save-excursion
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(re-search-backward
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(concat "\\(" customize-label "\\)") nil t)
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(help-xref-button 1 'help-customize-variable variable)))))
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;; Make a hyperlink to the library if appropriate. (Don't
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;; change the format of the buffer's initial line in case
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;; anything expects the current format.)
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(let ((file-name (symbol-file variable)))
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(when (equal file-name "loaddefs.el")
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;; Find the real def site of the preloaded variable.
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(let ((location
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(condition-case nil
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(find-variable-noselect variable file-name)
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(error nil))))
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(when location
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(with-current-buffer (car location)
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(goto-char (cdr location))
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(when (re-search-backward
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"^;;; Generated autoloads from \\(.*\\)" nil t)
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(setq file-name (match-string 1)))))))
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(when file-name
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(princ "\n\nDefined in `")
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(princ file-name)
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(princ "'.")
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(with-current-buffer standard-output
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(save-excursion
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(re-search-backward "`\\([^`']+\\)'" nil t)
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(help-xref-button 1 'help-variable-def
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variable file-name)))))
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(print-help-return-message)
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(save-excursion
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(set-buffer standard-output)
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;; Return the text we displayed.
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(buffer-string))))))))
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;;;###autoload
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(defun describe-syntax (&optional buffer)
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||
"Describe the syntax specifications in the syntax table of BUFFER.
|
||
The descriptions are inserted in a help buffer, which is then displayed.
|
||
BUFFER defaults to the current buffer."
|
||
(interactive)
|
||
(setq buffer (or buffer (current-buffer)))
|
||
(help-setup-xref (list #'describe-syntax buffer) (interactive-p))
|
||
(with-output-to-temp-buffer (help-buffer)
|
||
(let ((table (with-current-buffer buffer (syntax-table))))
|
||
(with-current-buffer standard-output
|
||
(describe-vector table 'internal-describe-syntax-value)
|
||
(while (setq table (char-table-parent table))
|
||
(insert "\nThe parent syntax table is:")
|
||
(describe-vector table 'internal-describe-syntax-value))))))
|
||
|
||
(defun help-describe-category-set (value)
|
||
(insert (cond
|
||
((null value) "default")
|
||
((char-table-p value) "deeper char-table ...")
|
||
(t (condition-case err
|
||
(category-set-mnemonics value)
|
||
(error "invalid"))))))
|
||
|
||
;;;###autoload
|
||
(defun describe-categories (&optional buffer)
|
||
"Describe the category specifications in the current category table.
|
||
The descriptions are inserted in a buffer, which is then displayed."
|
||
(interactive)
|
||
(setq buffer (or buffer (current-buffer)))
|
||
(help-setup-xref (list #'describe-categories buffer) (interactive-p))
|
||
(with-output-to-temp-buffer (help-buffer)
|
||
(let ((table (with-current-buffer buffer (category-table))))
|
||
(with-current-buffer standard-output
|
||
(describe-vector table 'help-describe-category-set)
|
||
(let ((docs (char-table-extra-slot table 0)))
|
||
(if (or (not (vectorp docs)) (/= (length docs) 95))
|
||
(insert "Invalid first extra slot in this char table\n")
|
||
(insert "Meanings of mnemonic characters are:\n")
|
||
(dotimes (i 95)
|
||
(let ((elt (aref docs i)))
|
||
(when elt
|
||
(insert (+ i ?\ ) ": " elt "\n"))))
|
||
(while (setq table (char-table-parent table))
|
||
(insert "\nThe parent category table is:")
|
||
(describe-vector table 'help-describe-category-set))))))))
|
||
|
||
(provide 'help-fns)
|
||
|
||
;;; help-fns.el ends here
|