;;; help-fns.el --- Complex help functions -*- lexical-binding: t -*-
;; Copyright (C) 1985-1986, 1993-1994, 1998-2012
;; Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: help, internal
;; Package: emacs
;; This file is part of GNU Emacs.
;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.
;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs. If not, see .
;;; Commentary:
;; This file contains those help commands which are complicated, and
;; which may not be used in every session. For example
;; `describe-function' will probably be heavily used when doing elisp
;; programming, but not if just editing C files. Simpler help commands
;; are in help.el
;;; Code:
;; Functions
;;;###autoload
(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
(and fn (symbol-name fn))))
(list (if (equal val "")
fn (intern val)))))
(if (null function)
(message "You didn't specify a function")
(help-setup-xref (list #'describe-function function)
(called-interactively-p 'interactive))
(save-excursion
(with-help-window (help-buffer)
(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)
(with-current-buffer standard-output
;; Return the text we displayed.
(buffer-string))))))
(defun help-split-fundoc (docstring def)
"Split a function DOCSTRING into the actual doc and the usage info.
Return (USAGE . DOC) or nil if there's no usage info, where USAGE info
is a string describing the argument list of DEF, such as
\"(apply FUNCTION &rest ARGUMENTS)\".
DEF is the function whose usage we're looking for in DOCSTRING."
;; Functions can get the calling sequence at the end of the doc string.
;; In cases where `function' has been fset to a subr we can't search for
;; function's name in the doc string so we use `fn' as the anonymous
;; function name instead.
(when (and docstring (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring))
(cons (format "(%s%s"
;; Replace `fn' with the actual function name.
(if (consp def) "anonymous" def)
(match-string 1 docstring))
(unless (zerop (match-beginning 0))
(substring docstring 0 (match-beginning 0))))))
;; FIXME: Move to subr.el?
(defun help-add-fundoc-usage (docstring arglist)
"Add the usage info to DOCSTRING.
If DOCSTRING already has a usage info, then just return it unchanged.
The usage info is built from ARGLIST. DOCSTRING can be nil.
ARGLIST can also be t or a string of the form \"(FUN ARG1 ARG2 ...)\"."
(unless (stringp docstring) (setq docstring ""))
(if (or (string-match "\n\n(fn\\(\\( .*\\)?)\\)\\'" docstring)
(eq arglist t))
docstring
(concat docstring
(if (string-match "\n?\n\\'" docstring)
(if (< (- (match-end 0) (match-beginning 0)) 2) "\n" "")
"\n\n")
(if (and (stringp arglist)
(string-match "\\`([^ ]+\\(.*\\))\\'" arglist))
(concat "(fn" (match-string 1 arglist) ")")
(format "%S" (help-make-usage 'fn arglist))))))
;; FIXME: Move to subr.el?
(defun help-function-arglist (def &optional preserve-names)
"Return a formal argument list for the function DEF.
IF PRESERVE-NAMES is non-nil, return a formal arglist that uses
the same names as used in the original source code, when possible."
;; Handle symbols aliased to other symbols.
(if (and (symbolp def) (fboundp def)) (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)))
(cond
((and (byte-code-function-p def) (listp (aref def 0))) (aref def 0))
((eq (car-safe def) 'lambda) (nth 1 def))
((eq (car-safe def) 'closure) (nth 2 def))
((or (and (byte-code-function-p def) (integerp (aref def 0)))
(subrp def))
(or (when preserve-names
(let* ((doc (condition-case nil (documentation def) (error nil)))
(docargs (if doc (car (help-split-fundoc doc nil))))
(arglist (if docargs
(cdar (read-from-string (downcase docargs)))))
(valid t))
;; Check validity.
(dolist (arg arglist)
(unless (and (symbolp arg)
(let ((name (symbol-name arg)))
(if (eq (aref name 0) ?&)
(memq arg '(&rest &optional))
(not (string-match "\\." name)))))
(setq valid nil)))
(when valid arglist)))
(let* ((args-desc (if (not (subrp def))
(aref def 0)
(let ((a (subr-arity def)))
(logior (car a)
(if (numberp (cdr a))
(lsh (cdr a) 8)
(lsh 1 7))))))
(max (lsh args-desc -8))
(min (logand args-desc 127))
(rest (logand args-desc 128))
(arglist ()))
(dotimes (i min)
(push (intern (concat "arg" (number-to-string (1+ i)))) arglist))
(when (> max min)
(push '&optional arglist)
(dotimes (i (- max min))
(push (intern (concat "arg" (number-to-string (+ 1 i min))))
arglist)))
(unless (zerop rest) (push '&rest arglist) (push 'rest arglist))
(nreverse arglist))))
((and (autoloadp def) (not (eq (nth 4 def) 'keymap)))
"[Arg list not available until function definition is loaded.]")
(t t)))
;; FIXME: Move to subr.el?
(defun help-make-usage (function arglist)
(cons (if (symbolp function) function 'anonymous)
(mapcar (lambda (arg)
(if (not (symbolp arg)) arg
(let ((name (symbol-name arg)))
(cond
((string-match "\\`&" name) arg)
((string-match "\\`_" name)
(intern (upcase (substring name 1))))
(t (intern (upcase name)))))))
arglist)))
;; Could be this, if we make symbol-file do the work below.
;; (defun help-C-file-name (subr-or-var kind)
;; "Return the name of the C file where SUBR-OR-VAR is defined.
;; KIND should be `var' for a variable or `subr' for a subroutine."
;; (symbol-file (if (symbolp subr-or-var) subr-or-var
;; (subr-name subr-or-var))
;; (if (eq kind 'var) 'defvar 'defun)))
;;;###autoload
(defun help-C-file-name (subr-or-var kind)
"Return the name of the C file where SUBR-OR-VAR is defined.
KIND should be `var' for a variable or `subr' for a subroutine."
(let ((docbuf (get-buffer-create " *DOC*"))
(name (if (eq 'var kind)
(concat "V" (symbol-name subr-or-var))
(concat "F" (subr-name subr-or-var)))))
(with-current-buffer docbuf
(goto-char (point-min))
(if (eobp)
(insert-file-contents-literally
(expand-file-name internal-doc-file-name doc-directory)))
(let ((file (catch 'loop
(while t
(let ((pnt (search-forward (concat " " name "\n"))))
(re-search-backward " S\\(.*\\)")
(let ((file (match-string 1)))
(if (member file build-files)
(throw 'loop file)
(goto-char pnt))))))))
(if (string-match "^ns.*\\(\\.o\\|obj\\)\\'" file)
(setq file (replace-match ".m" t t file 1))
(if (string-match "\\.\\(o\\|obj\\)\\'" file)
(setq file (replace-match ".c" t t file))))
(if (string-match "\\.\\(c\\|m\\)\\'" file)
(concat "src/" file)
file)))))
(defcustom help-downcase-arguments nil
"If non-nil, argument names in *Help* buffers are downcased."
:type 'boolean
:group 'help
:version "23.2")
(defun help-highlight-arg (arg)
"Highlight ARG as an argument name for a *Help* buffer.
Return ARG in face `help-argument-name'; ARG is also downcased
if the variable `help-downcase-arguments' is non-nil."
(propertize (if help-downcase-arguments (downcase arg) arg)
'face 'help-argument-name))
(defun help-do-arg-highlight (doc args)
(with-syntax-table (make-syntax-table emacs-lisp-mode-syntax-table)
(modify-syntax-entry ?\- "w")
(dolist (arg args)
(setq doc (replace-regexp-in-string
;; This is heuristic, but covers all common cases
;; except ARG1-ARG2
(concat "\\<" ; beginning of word
"\\(?:[a-z-]*-\\)?" ; for xxx-ARG
"\\("
(regexp-quote arg)
"\\)"
"\\(?:es\\|s\\|th\\)?" ; for ARGth, ARGs
"\\(?:-[a-z0-9-]+\\)?" ; for ARG-xxx, ARG-n
"\\(?:-[{([<`\"].*?\\)?"; for ARG-{x}, (x), , [x], `x'
"\\>") ; end of word
(help-highlight-arg arg)
doc t t 1)))
doc))
(defun help-highlight-arguments (usage doc &rest args)
(when (and usage (string-match "^(" usage))
(with-temp-buffer
(insert usage)
(goto-char (point-min))
(let ((case-fold-search nil)
(next (not (or args (looking-at "\\["))))
(opt nil))
;; Make a list of all arguments
(skip-chars-forward "^ ")
(while next
(or opt (not (looking-at " &")) (setq opt t))
(if (not (re-search-forward " \\([\\[(]*\\)\\([^] &)\.]+\\)" nil t))
(setq next nil)
(setq args (cons (match-string 2) args))
(when (and opt (string= (match-string 1) "("))
;; A pesky CL-style optional argument with default value,
;; so let's skip over it
(search-backward "(")
(goto-char (scan-sexps (point) 1)))))
;; Highlight arguments in the USAGE string
(setq usage (help-do-arg-highlight (buffer-string) args))
;; Highlight arguments in the DOC string
(setq doc (and doc (help-do-arg-highlight doc args))))))
;; Return value is like the one from help-split-fundoc, but highlighted
(cons usage doc))
;; The following function was compiled from the former functions
;; `describe-simplify-lib-file-name' and `find-source-lisp-file' with
;; some excerpts from `describe-function-1' and `describe-variable'.
;; The only additional twists provided are (1) locate the defining file
;; for autoloaded functions, and (2) give preference to files in the
;; "install directory" (directories found via `load-path') rather than
;; to files in the "compile directory" (directories found by searching
;; the loaddefs.el file). We autoload it because it's also used by
;; `describe-face' (instead of `describe-simplify-lib-file-name').
;;;###autoload
(defun find-lisp-object-file-name (object type)
"Guess the file that defined the Lisp object OBJECT, of type TYPE.
OBJECT should be a symbol associated with a function, variable, or face;
alternatively, it can be a function definition.
If TYPE is `defvar', search for a variable definition.
If TYPE is `defface', search for a face definition.
If TYPE is the value returned by `symbol-function' for a function symbol,
search for a function definition.
The return value is the absolute name of a readable file where OBJECT is
defined. If several such files exist, preference is given to a file
found via `load-path'. The return value can also be `C-source', which
means that OBJECT is a function or variable defined in C. If no
suitable file is found, return nil."
(let* ((autoloaded (autoloadp type))
(file-name (or (and autoloaded (nth 1 type))
(symbol-file
object (if (memq type (list 'defvar 'defface))
type
'defun)))))
(cond
(autoloaded
;; An autoloaded function: Locate the file since `symbol-function'
;; has only returned a bare string here.
(setq file-name
(locate-file file-name load-path '(".el" ".elc") 'readable)))
((and (stringp file-name)
(string-match "[.]*loaddefs.el\\'" file-name))
;; An autoloaded variable or face. Visit loaddefs.el in a buffer
;; and try to extract the defining file. The following form is
;; from `describe-function-1' and `describe-variable'.
(let ((location
(condition-case nil
(find-function-search-for-symbol object nil file-name)
(error nil))))
(when (cdr location)
(with-current-buffer (car location)
(goto-char (cdr location))
(when (re-search-backward
"^;;; Generated autoloads from \\(.*\\)" nil t)
(setq file-name
(locate-file
(file-name-sans-extension
(match-string-no-properties 1))
load-path '(".el" ".elc") 'readable))))))))
(cond
((and (not file-name) (subrp type))
;; A built-in function. The form is from `describe-function-1'.
(if (get-buffer " *DOC*")
(help-C-file-name type 'subr)
'C-source))
((and (not file-name) (symbolp object)
(integerp (get object 'variable-documentation)))
;; A variable defined in C. The form is from `describe-variable'.
(if (get-buffer " *DOC*")
(help-C-file-name object 'var)
'C-source))
((not (stringp file-name))
;; If we don't have a file-name string by now, we lost.
nil)
;; Now, `file-name' should have become an absolute file name.
;; For files loaded from ~/.emacs.elc, try ~/.emacs.
((let (fn)
(and (string-equal file-name
(expand-file-name ".emacs.elc" "~"))
(file-readable-p (setq fn (expand-file-name ".emacs" "~")))
fn)))
;; When the Elisp source file can be found in the install
;; directory, return the name of that file.
((let ((lib-name
(if (string-match "[.]elc\\'" file-name)
(substring-no-properties file-name 0 -1)
file-name)))
(or (and (file-readable-p lib-name) lib-name)
;; The library might be compressed.
(and (file-readable-p (concat lib-name ".gz")) lib-name))))
((let* ((lib-name (file-name-nondirectory file-name))
;; The next form is from `describe-simplify-lib-file-name'.
(file-name
;; Try converting the absolute file name to a library
;; name, convert that back to a file name and see if we
;; get the original one. If so, they are equivalent.
(if (equal file-name (locate-file lib-name load-path '("")))
(if (string-match "[.]elc\\'" lib-name)
(substring-no-properties lib-name 0 -1)
lib-name)
file-name))
;; The next three forms are from `find-source-lisp-file'.
(elc-file (locate-file
(concat file-name
(if (string-match "\\.el\\'" file-name)
"c"
".elc"))
load-path nil 'readable))
(str (when elc-file
(with-temp-buffer
(insert-file-contents-literally elc-file nil 0 256)
(buffer-string))))
(src-file (and str
(string-match ";;; from file \\(.*\\.el\\)" str)
(match-string 1 str))))
(and src-file (file-readable-p src-file) src-file))))))
(declare-function ad-get-advice-info "advice" (function))
(defun help-fns--key-bindings (function)
(when (commandp function)
(let ((pt2 (with-current-buffer standard-output (point)))
(remapped (command-remapping function)))
(unless (memq remapped '(ignore undefined))
(let ((keys (where-is-internal
(or remapped function) overriding-local-map nil nil))
non-modified-keys)
(if (and (eq function 'self-insert-command)
(vectorp (car-safe keys))
(consp (aref (car keys) 0)))
(princ "It is bound to many ordinary text characters.\n")
;; Which non-control non-meta keys run this command?
(dolist (key keys)
(if (member (event-modifiers (aref key 0)) '(nil (shift)))
(push key non-modified-keys)))
(when remapped
(princ "Its keys are remapped to `")
(princ (symbol-name remapped))
(princ "'.\n"))
(when keys
(princ (if remapped
"Without this remapping, it would be bound to "
"It is bound to "))
;; If lots of ordinary text characters run this command,
;; don't mention them one by one.
(if (< (length non-modified-keys) 10)
(princ (mapconcat 'key-description keys ", "))
(dolist (key non-modified-keys)
(setq keys (delq key keys)))
(if keys
(progn
(princ (mapconcat 'key-description keys ", "))
(princ ", and many ordinary text characters"))
(princ "many ordinary text characters"))))
(when (or remapped keys non-modified-keys)
(princ ".")
(terpri)))))
(with-current-buffer standard-output
(fill-region-as-paragraph pt2 (point))
(unless (looking-back "\n\n")
(terpri))))))
(defun help-fns--compiler-macro (function)
(let ((handler (function-get function 'compiler-macro)))
(when handler
(insert "\nThis function has a compiler macro")
(let ((lib (get function 'compiler-macro-file)))
;; FIXME: rather than look at the compiler-macro-file property,
;; just look at `handler' itself.
(when (stringp lib)
(insert (format " in `%s'" lib))
(save-excursion
(re-search-backward "`\\([^`']+\\)'" nil t)
(help-xref-button 1 'help-function-cmacro function lib))))
(insert ".\n"))))
(defun help-fns--signature (function doc real-def real-function)
(unless (keymapp function) ; If definition is a keymap, skip arglist note.
(let* ((advertised (gethash real-def advertised-signature-table t))
(arglist (if (listp advertised)
advertised (help-function-arglist real-def)))
(usage (help-split-fundoc doc function)))
(if usage (setq doc (cdr usage)))
(let* ((use (cond
((and usage (not (listp advertised))) (car usage))
((listp arglist)
(format "%S" (help-make-usage function arglist)))
((stringp arglist) arglist)
;; Maybe the arglist is in the docstring of a symbol
;; this one is aliased to.
((let ((fun real-function))
(while (and (symbolp fun)
(setq fun (symbol-function fun))
(not (setq usage (help-split-fundoc
(documentation fun)
function)))))
usage)
(car usage))
((or (stringp real-def)
(vectorp real-def))
(format "\nMacro: %s" (format-kbd-macro real-def)))
(t "[Missing arglist. Please make a bug report.]")))
(high (help-highlight-arguments use doc)))
(let ((fill-begin (point)))
(insert (car high) "\n")
(fill-region fill-begin (point)))
(cdr high)))))
(defun help-fns--parent-mode (function)
;; If this is a derived mode, link to the parent.
(let ((parent-mode (and (symbolp function)
(get function
'derived-mode-parent))))
(when parent-mode
(insert "\nParent mode: `")
(let ((beg (point)))
(insert (format "%s" parent-mode))
(make-text-button beg (point)
'type 'help-function
'help-args (list parent-mode)))
(insert "'.\n"))))
(defun help-fns--obsolete (function)
(let* ((obsolete (and
;; `function' might be a lambda construct.
(symbolp function)
(get function 'byte-obsolete-info)))
(use (car obsolete)))
(when obsolete
(insert "\nThis function is obsolete")
(when (nth 2 obsolete)
(insert (format " since %s" (nth 2 obsolete))))
(insert (cond ((stringp use) (concat ";\n" use))
(use (format ";\nuse `%s' instead." use))
(t "."))
"\n"))))
;; We could use `symbol-file' but this is a wee bit more efficient.
(defun help-fns--autoloaded-p (function file)
"Return non-nil if FUNCTION has previously been autoloaded.
FILE is the file where FUNCTION was probably defined."
(let* ((file (file-name-sans-extension (file-truename file)))
(load-hist load-history)
(target (cons t function))
found)
(while (and load-hist (not found))
(and (caar load-hist)
(equal (file-name-sans-extension (caar load-hist)) file)
(setq found (member target (cdar load-hist))))
(setq load-hist (cdr load-hist)))
found))
;;;###autoload
(defun describe-function-1 (function)
(let* ((advised (and (symbolp function) (featurep 'advice)
(ad-get-advice-info function)))
;; If the function is advised, use the symbol that has the
;; real definition, if that symbol is already set up.
(real-function
(or (and advised
(let ((origname (cdr (assq 'origname advised))))
(and (fboundp origname) origname)))
function))
;; Get the real definition.
(def (if (symbolp real-function)
(symbol-function real-function)
function))
(aliased (symbolp def))
(real-def (if aliased
(let ((f def))
(while (and (fboundp f)
(symbolp (symbol-function f)))
(setq f (symbol-function f)))
f)
def))
(file-name (find-lisp-object-file-name function def))
(pt1 (with-current-buffer (help-buffer) (point)))
(beg (if (and (or (byte-code-function-p def)
(keymapp def)
(memq (car-safe def) '(macro lambda closure)))
file-name
(help-fns--autoloaded-p function file-name))
(if (commandp def)
"an interactive autoloaded "
"an autoloaded ")
(if (commandp def) "an interactive " "a "))))
;; Print what kind of function-like object FUNCTION is.
(princ (cond ((or (stringp def) (vectorp def))
"a keyboard macro")
((subrp def)
(if (eq 'unevalled (cdr (subr-arity def)))
(concat beg "special form")
(concat beg "built-in function")))
((byte-code-function-p def)
(concat beg "compiled Lisp function"))
(aliased
(format "an alias for `%s'" real-def))
((eq (car-safe def) 'lambda)
(concat beg "Lisp function"))
((eq (car-safe def) 'macro)
(concat beg "Lisp macro"))
((eq (car-safe def) 'closure)
(concat beg "Lisp closure"))
((autoloadp def)
(format "%s autoloaded %s"
(if (commandp def) "an interactive" "an")
(if (eq (nth 4 def) 'keymap) "keymap"
(if (nth 4 def) "Lisp macro" "Lisp function"))))
((keymapp def)
(let ((is-full nil)
(elts (cdr-safe def)))
(while elts
(if (char-table-p (car-safe elts))
(setq is-full t
elts nil))
(setq elts (cdr-safe elts)))
(concat beg (if is-full "keymap" "sparse keymap"))))
(t "")))
(if (and aliased (not (fboundp real-def)))
(princ ",\nwhich is not defined. Please make a bug report.")
(with-current-buffer standard-output
(save-excursion
(save-match-data
(when (re-search-backward "alias for `\\([^`']+\\)'" nil t)
(help-xref-button 1 'help-function real-def)))))
(when file-name
(princ " in `")
;; We used to add .el to the file name,
;; but that's completely wrong when the user used load-file.
(princ (if (eq file-name 'C-source)
"C source code"
(file-name-nondirectory file-name)))
(princ "'")
;; Make a hyperlink to the library.
(with-current-buffer standard-output
(save-excursion
(re-search-backward "`\\([^`']+\\)'" nil t)
(help-xref-button 1 'help-function-def function file-name))))
(princ ".")
(with-current-buffer (help-buffer)
(fill-region-as-paragraph (save-excursion (goto-char pt1) (forward-line 0) (point))
(point)))
(terpri)(terpri)
(let* ((doc-raw (condition-case err
(documentation function t)
(error (format "No Doc! %S" err))))
;; If the function is autoloaded, and its docstring has
;; key substitution constructs, load the library.
(doc (progn
(and (autoloadp real-def)
help-enable-auto-load
(string-match "\\([^\\]=\\|[^=]\\|\\`\\)\\\\[[{<]"
doc-raw)
(load (cadr real-def) t))
(substitute-command-keys doc-raw))))
(help-fns--key-bindings function)
(with-current-buffer standard-output
(setq doc (help-fns--signature function doc real-def real-function))
(help-fns--compiler-macro function)
(help-fns--parent-mode function)
(help-fns--obsolete function)
(insert "\n"
(or doc "Not documented.")))))))
;; Variables
;;;###autoload
(defun variable-at-point (&optional any-symbol)
"Return the bound variable symbol found at or before point.
Return 0 if there is no such symbol.
If ANY-SYMBOL is non-nil, don't insist the symbol be bound."
(with-syntax-table emacs-lisp-mode-syntax-table
(or (condition-case ()
(save-excursion
(skip-chars-forward "'")
(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) (boundp obj) obj)))
(error nil))
(let* ((str (find-tag-default))
(sym (if str (intern-soft str))))
(if (and sym (or any-symbol (boundp sym)))
sym
(save-match-data
(when (and str (string-match "\\`\\W*\\(.*?\\)\\W*\\'" str))
(setq sym (intern-soft (match-string 1 str)))
(and (or any-symbol (boundp sym)) sym)))))
0)))
(defun describe-variable-custom-version-info (variable)
(let ((custom-version (get variable 'custom-version))
(cpv (get variable 'custom-package-version))
(output nil))
(if custom-version
(setq output
(format "This variable was introduced, or its default value was changed, in\nversion %s of Emacs.\n"
custom-version))
(when cpv
(let* ((package (car-safe cpv))
(version (if (listp (cdr-safe cpv))
(car (cdr-safe cpv))
(cdr-safe cpv)))
(pkg-versions (assq package customize-package-emacs-version-alist))
(emacsv (cdr (assoc version pkg-versions))))
(if (and package version)
(setq output
(format (concat "This variable was introduced, or its default value was changed, in\nversion %s of the %s package"
(if emacsv
(format " that is part of Emacs %s" emacsv))
".\n")
version package))))))
output))
;;;###autoload
(defun describe-variable (variable &optional buffer frame)
"Display the full documentation of VARIABLE (a symbol).
Returns the documentation as a string, also.
If VARIABLE has a buffer-local value in BUFFER or FRAME
\(default to the current buffer and current frame),
it is displayed along with the global value."
(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
(lambda (vv)
(or (get vv 'variable-documentation)
(and (boundp vv) (not (keywordp vv)))))
t nil nil
(if (symbolp v) (symbol-name v))))
(list (if (equal val "")
v (intern val)))))
(let (file-name)
(unless (buffer-live-p buffer) (setq buffer (current-buffer)))
(unless (frame-live-p frame) (setq frame (selected-frame)))
(if (not (symbolp variable))
(message "You did not specify a variable")
(save-excursion
(let ((valvoid (not (with-current-buffer buffer (boundp variable))))
(permanent-local (get variable 'permanent-local))
val val-start-pos locus)
;; Extract the value before setting up the output buffer,
;; in case `buffer' *is* the output buffer.
(unless valvoid
(with-selected-frame frame
(with-current-buffer buffer
(setq val (symbol-value variable)
locus (variable-binding-locus variable)))))
(help-setup-xref (list #'describe-variable variable buffer)
(called-interactively-p 'interactive))
(with-help-window (help-buffer)
(with-current-buffer buffer
(prin1 variable)
(setq file-name (find-lisp-object-file-name variable 'defvar))
(if file-name
(progn
(princ " is a variable defined in `")
(princ (if (eq file-name 'C-source)
"C source code"
(file-name-nondirectory file-name)))
(princ "'.\n")
(with-current-buffer standard-output
(save-excursion
(re-search-backward "`\\([^`']+\\)'" nil t)
(help-xref-button 1 'help-variable-def
variable file-name)))
(if valvoid
(princ "It is void as a variable.")
(princ "Its ")))
(if valvoid
(princ " is void as a variable.")
(princ "'s "))))
(unless valvoid
(with-current-buffer standard-output
(setq val-start-pos (point))
(princ "value is ")
(let ((from (point))
(line-beg (line-beginning-position))
(print-rep
(let ((print-quoted t))
(prin1-to-string val))))
(if (< (+ (length print-rep) (point) (- line-beg)) 68)
(insert print-rep)
(terpri)
(pp val)
(if (< (point) (+ 68 (line-beginning-position 0)))
(delete-region from (1+ from))
(delete-region (1- from) from)))
(let* ((sv (get variable 'standard-value))
(origval (and (consp sv)
(condition-case nil
(eval (car sv))
(error :help-eval-error)))))
(when (and (consp sv)
(not (equal origval val))
(not (equal origval :help-eval-error)))
(princ "\nOriginal value was \n")
(setq from (point))
(pp origval)
(if (< (point) (+ from 20))
(delete-region (1- from) from)))))))
(terpri)
(when locus
(cond
((bufferp locus)
(princ (format "Local in buffer %s; "
(buffer-name))))
((framep locus)
(princ (format "It is a frame-local variable; ")))
((terminal-live-p locus)
(princ (format "It is a terminal-local variable; ")))
(t
(princ (format "It is local to %S" locus))))
(if (not (default-boundp variable))
(princ "globally void")
(let ((global-val (default-value variable)))
(with-current-buffer standard-output
(princ "global value is ")
(if (eq val global-val)
(princ "the same.")
(terpri)
;; Fixme: pp can take an age if you happen to
;; ask for a very large expression. We should
;; probably print it raw once and check it's a
;; sensible size before prettyprinting. -- fx
(let ((from (point)))
(pp global-val)
;; See previous comment for this function.
;; (help-xref-on-pp from (point))
(if (< (point) (+ from 20))
(delete-region (1- from) from)))))))
(terpri))
;; If the value is large, move it to the end.
(with-current-buffer standard-output
(when (> (count-lines (point-min) (point-max)) 10)
;; Note that setting the syntax table like below
;; makes forward-sexp move over a `'s' at the end
;; of a symbol.
(set-syntax-table emacs-lisp-mode-syntax-table)
(goto-char val-start-pos)
;; The line below previously read as
;; (delete-region (point) (progn (end-of-line) (point)))
;; which suppressed display of the buffer local value for
;; large values.
(when (looking-at "value is") (replace-match ""))
(save-excursion
(insert "\n\nValue:")
(set (make-local-variable 'help-button-cache)
(point-marker)))
(insert "value is shown ")
(insert-button "below"
'action help-button-cache
'follow-link t
'help-echo "mouse-2, RET: show value")
(insert ".\n")))
(terpri)
(let* ((alias (condition-case nil
(indirect-variable variable)
(error variable)))
(obsolete (get variable 'byte-obsolete-variable))
(use (car obsolete))
(safe-var (get variable 'safe-local-variable))
(doc (condition-case err
(or (documentation-property
variable 'variable-documentation)
(documentation-property
alias 'variable-documentation))
(error (format "Doc not found: %S" err))))
(extra-line nil))
;; Mention if it's a local variable.
(cond
((and (local-variable-if-set-p variable)
(or (not (local-variable-p variable))
(with-temp-buffer
(local-variable-if-set-p variable))))
(setq extra-line t)
(princ " Automatically becomes ")
(if permanent-local
(princ "permanently "))
(princ "buffer-local when set.\n"))
((not permanent-local))
((bufferp locus)
(princ " This variable's buffer-local value is permanent.\n"))
(t
(princ " This variable's value is permanent \
if it is given a local binding.\n")))
;; Mention if it's an alias.
(unless (eq alias variable)
(setq extra-line t)
(princ (format " This variable is an alias for `%s'.\n" alias)))
(when obsolete
(setq extra-line t)
(princ " This variable is obsolete")
(if (nth 2 obsolete)
(princ (format " since %s" (nth 2 obsolete))))
(princ (cond ((stringp use) (concat ";\n " use))
(use (format ";\n use `%s' instead." (car obsolete)))
(t ".")))
(terpri))
(when (member (cons variable val) file-local-variables-alist)
(setq extra-line t)
(if (member (cons variable val) dir-local-variables-alist)
(let ((file (and (buffer-file-name)
(not (file-remote-p (buffer-file-name)))
(dir-locals-find-file
(buffer-file-name))))
(dir-file t))
(princ " This variable's value is directory-local")
(if (null file)
(princ ".\n")
(princ ", set ")
(if (consp file) ; result from cache
;; If the cache element has an mtime, we
;; assume it came from a file.
(if (nth 2 file)
(setq file (expand-file-name
dir-locals-file (car file)))
;; Otherwise, assume it was set directly.
(setq dir-file nil)))
(princ (if dir-file
"by the file\n `"
"for the directory\n `"))
(with-current-buffer standard-output
(insert-text-button
file 'type 'help-dir-local-var-def
'help-args (list variable file)))
(princ "'.\n")))
(princ " This variable's value is file-local.\n")))
(when (memq variable ignored-local-variables)
(setq extra-line t)
(princ " This variable is ignored as a file-local \
variable.\n"))
;; Can be both risky and safe, eg auto-fill-function.
(when (risky-local-variable-p variable)
(setq extra-line t)
(princ " This variable may be risky if used as a \
file-local variable.\n")
(when (assq variable safe-local-variable-values)
(princ " However, you have added it to \
`safe-local-variable-values'.\n")))
(when safe-var
(setq extra-line t)
(princ " This variable is safe as a file local variable ")
(princ "if its value\n satisfies the predicate ")
(princ (if (byte-code-function-p safe-var)
"which is byte-compiled expression.\n"
(format "`%s'.\n" safe-var))))
(if extra-line (terpri))
(princ "Documentation:\n")
(with-current-buffer standard-output
(insert (or doc "Not documented as a variable."))))
;; Make a link to customize if this variable can be customized.
(when (custom-variable-p variable)
(let ((customize-label "customize"))
(terpri)
(terpri)
(princ (concat "You can " customize-label " this variable."))
(with-current-buffer standard-output
(save-excursion
(re-search-backward
(concat "\\(" customize-label "\\)") nil t)
(help-xref-button 1 'help-customize-variable variable))))
;; Note variable's version or package version
(let ((output (describe-variable-custom-version-info variable)))
(when output
(terpri)
(terpri)
(princ output))))
(with-current-buffer standard-output
;; Return the text we displayed.
(buffer-string))))))))
;;;###autoload
(defun describe-syntax (&optional buffer)
"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)
(called-interactively-p 'interactive))
(with-help-window (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 nil
(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.
If BUFFER is non-nil, then describe BUFFER's category table instead.
BUFFER should be a buffer or a buffer name."
(interactive)
(setq buffer (or buffer (current-buffer)))
(help-setup-xref (list #'describe-categories buffer)
(called-interactively-p 'interactive))
(with-help-window (help-buffer)
(let* ((table (with-current-buffer buffer (category-table)))
(docs (char-table-extra-slot table 0)))
(if (or (not (vectorp docs)) (/= (length docs) 95))
(error "Invalid first extra slot in this category table\n"))
(with-current-buffer standard-output
(insert "Legend of category mnemonics (see the tail for the longer description)\n")
(let ((pos (point)) (items 0) lines n)
(dotimes (i 95)
(if (aref docs i) (setq items (1+ items))))
(setq lines (1+ (/ (1- items) 4)))
(setq n 0)
(dotimes (i 95)
(let ((elt (aref docs i)))
(when elt
(string-match ".*" elt)
(setq elt (match-string 0 elt))
(if (>= (length elt) 17)
(setq elt (concat (substring elt 0 14) "...")))
(if (< (point) (point-max))
(move-to-column (* 20 (/ n lines)) t))
(insert (+ i ?\s) ?: elt)
(if (< (point) (point-max))
(forward-line 1)
(insert "\n"))
(setq n (1+ n))
(if (= (% n lines) 0)
(goto-char pos))))))
(goto-char (point-max))
(insert "\n"
"character(s)\tcategory mnemonics\n"
"------------\t------------------")
(describe-vector table 'help-describe-category-set)
(insert "Legend of category mnemonics:\n")
(dotimes (i 95)
(let ((elt (aref docs i)))
(when elt
(if (string-match "\n" elt)
(setq elt (substring elt (match-end 0))))
(insert (+ i ?\s) ": " elt "\n"))))
(while (setq table (char-table-parent table))
(insert "\nThe parent category table is:")
(describe-vector table 'help-describe-category-set))))))
;;; Replacements for old lib-src/ programs. Don't seem especially useful.
;; Replaces lib-src/digest-doc.c.
;;;###autoload
(defun doc-file-to-man (file)
"Produce an nroff buffer containing the doc-strings from the DOC file."
(interactive (list (read-file-name "Name of DOC file: " doc-directory
internal-doc-file-name t)))
(or (file-readable-p file)
(error "Cannot read file `%s'" file))
(pop-to-buffer (generate-new-buffer "*man-doc*"))
(setq buffer-undo-list t)
(insert ".TH \"Command Summary for GNU Emacs\"\n"
".AU Richard M. Stallman\n")
(insert-file-contents file)
(let (notfirst)
(while (search-forward " " nil 'move)
(if (looking-at "S")
(delete-region (1- (point)) (line-end-position))
(delete-char -1)
(if notfirst
(insert "\n.DE\n")
(setq notfirst t))
(insert "\n.SH ")
(insert (if (looking-at "F") "Function " "Variable "))
(delete-char 1)
(forward-line 1)
(insert ".DS L\n"))))
(insert "\n.DE\n")
(setq buffer-undo-list nil)
(nroff-mode))
;; Replaces lib-src/sorted-doc.c.
;;;###autoload
(defun doc-file-to-info (file)
"Produce a texinfo buffer with sorted doc-strings from the DOC file."
(interactive (list (read-file-name "Name of DOC file: " doc-directory
internal-doc-file-name t)))
(or (file-readable-p file)
(error "Cannot read file `%s'" file))
(let ((i 0) type name doc alist)
(with-temp-buffer
(insert-file-contents file)
;; The characters "@{}" need special treatment.
(while (re-search-forward "[@{}]" nil t)
(backward-char)
(insert "@")
(forward-char 1))
(goto-char (point-min))
(while (search-forward " " nil t)
(unless (looking-at "S")
(setq type (char-after)
name (buffer-substring (1+ (point)) (line-end-position))
doc (buffer-substring (line-beginning-position 2)
(if (search-forward " " nil 'move)
(1- (point))
(point)))
alist (cons (list name type doc) alist))
(backward-char 1))))
(pop-to-buffer (generate-new-buffer "*info-doc*"))
(setq buffer-undo-list t)
;; Write the output header.
(insert "\\input texinfo @c -*-texinfo-*-\n"
"@setfilename emacsdoc.info\n"
"@settitle Command Summary for GNU Emacs\n"
"@finalout\n"
"\n@node Top\n"
"@unnumbered Command Summary for GNU Emacs\n\n"
"@table @asis\n\n"
"@iftex\n"
"@global@let@ITEM@item\n"
"@def@item{@filbreak@vskip5pt@ITEM}\n"
"@font@tensy cmsy10 scaled @magstephalf\n"
"@font@teni cmmi10 scaled @magstephalf\n"
"@def\\{{@tensy@char110}}\n" ; this backslash goes with cmr10
"@def|{{@tensy@char106}}\n"
"@def@{{{@tensy@char102}}\n"
"@def@}{{@tensy@char103}}\n"
"@def<{{@teni@char62}}\n"
"@def>{{@teni@char60}}\n"
"@chardef@@64\n"
"@catcode43=12\n"
"@tableindent-0.2in\n"
"@end iftex\n")
;; Sort the array by name; within each name, by type (functions first).
(setq alist (sort alist (lambda (e1 e2)
(if (string-equal (car e1) (car e2))
(<= (cadr e1) (cadr e2))
(string-lessp (car e1) (car e2))))))
;; Print each function.
(dolist (e alist)
(insert "\n@item "
(if (char-equal (cadr e) ?\F) "Function" "Variable")
" @code{" (car e) "}\n@display\n"
(nth 2 e)
"\n@end display\n")
;; Try to avoid a save size overflow in the TeX output routine.
(if (zerop (setq i (% (1+ i) 100)))
(insert "\n@end table\n@table @asis\n")))
(insert "@end table\n"
"@bye\n")
(setq buffer-undo-list nil)
(texinfo-mode)))
(provide 'help-fns)
;;; help-fns.el ends here