;;; help.el --- help commands for Emacs
-;; Copyright (C) 1985, 1986, 1993, 1994, 1998 Free Software Foundation, Inc.
+;; Copyright (C) 1985, 1986, 1993, 1994, 1998, 1999 Free Software Foundation, Inc.
;; Maintainer: FSF
;; Keywords: help, internal
;;; Commentary:
;; This code implements GNU Emacs' on-line help system, the one invoked by
-;;`M-x help-for-help'.
+;; `M-x help-for-help'.
;;; Code:
;; Get the macro make-help-screen when this is compiled,
;; or run interpreted, but not when the compiled code is loaded.
(eval-when-compile (require 'help-macro))
+(eval-when-compile (require 'view))
(defvar help-map (make-sparse-keymap)
"Keymap for characters following the Help key.")
(define-key help-map "F" 'view-emacs-FAQ)
(define-key help-map "i" 'info)
+(define-key help-map "4i" 'info-other-window)
(define-key help-map "\C-f" 'Info-goto-emacs-command-node)
(define-key help-map "\C-k" 'Info-goto-emacs-key-command-node)
(define-key help-map "\C-i" 'info-lookup-symbol)
(defvar help-xref-stack nil
"A stack of ways by which to return to help buffers after following xrefs.
-Used by `help-follow' and `help-xref-go-back'.")
+Used by `help-follow' and `help-xref-go-back'.
+An element looks like (POSITION FUNCTION ARGS...).
+To use the element, do (apply FUNCTION ARGS) then (goto-char POSITION).")
(put 'help-xref-stack 'permanent-local t)
(defvar help-xref-stack-item nil
- "An item for `help-follow' in this buffer to push onto `help-xref-stack'.")
+ "An item for `help-follow' in this buffer to push onto `help-xref-stack'.
+The format is (FUNCTION ARGS...).")
(put 'help-xref-stack-item 'permanent-local t)
(setq-default help-xref-stack nil help-xref-stack-item nil)
+(defcustom help-mode-hook nil
+ "Hook run by `help-mode'."
+ :type 'hook
+ :group 'help)
+
(defun help-mode ()
"Major mode for viewing help text and navigating references in it.
Entry to this mode runs the normal hook `help-mode-hook'.
;; `help-mode-maybe'.
(run-hooks 'help-mode-hook))
-(defun help-mode-maybe ()
- (if (eq major-mode 'fundamental-mode)
- (help-mode))
+(defun help-mode-setup ()
+ (help-mode)
+ (setq buffer-read-only nil))
+
+(add-hook 'temp-buffer-setup-hook 'help-mode-setup)
+
+(defun help-mode-finish ()
(when (eq major-mode 'help-mode)
;; View mode's read-only status of existing *Help* buffer is lost
;; by with-output-to-temp-buffer.
(setq view-return-to-alist
(list (cons (selected-window) help-return-method))))
-(add-hook 'temp-buffer-show-hook 'help-mode-maybe)
+(add-hook 'temp-buffer-show-hook 'help-mode-finish)
(defun help-quit ()
+ "Just exit from the Help command's command loop."
(interactive)
nil)
(goto-char (point-min))
(set-buffer-modified-p nil))))
+(defun mode-line-key-binding (key)
+ "Value is the binding of KEY in the mode line or nil if none."
+ (let (string-info defn)
+ (when (and (eq 'mode-line (aref key 0))
+ (consp (setq string-info (nth 4 (event-start (aref key 1))))))
+ (let* ((string (car string-info))
+ (pos (cdr string-info))
+ (local-map (and (> pos 0)
+ (< pos (length string))
+ (get-text-property pos 'local-map string))))
+ (setq defn (and local-map (lookup-key local-map key)))))
+ defn))
+
(defun describe-key-briefly (key &optional insert)
"Print the name of the function KEY invokes. KEY is a string.
If INSERT (the prefix arg) is non-nil, insert the message in the buffer."
(interactive "kDescribe key briefly: \nP")
- ;; If this key seq ends with a down event, discard the
- ;; following click or drag event. Otherwise that would
- ;; erase the message.
- (let ((type (aref key (1- (length key)))))
- (if (listp type) (setq type (car type)))
- (and (symbolp type)
- (memq 'down (event-modifiers type))
- (read-event)))
(save-excursion
(let ((modifiers (event-modifiers (aref key 0)))
(standard-output (if insert (current-buffer) t))
(set-buffer (window-buffer window))
(goto-char position)))
;; Ok, now look up the key and name the command.
- (let ((defn (key-binding key))
+ (let ((defn (or (mode-line-key-binding key)
+ (key-binding key)))
(key-desc (key-description key)))
(if (or (null defn) (integerp defn))
(princ (format "%s is undefined" key-desc))
(princ (format (if insert
- "%s (%s)"
+ "`%s' (`%s')"
(if (windowp window)
"%s at that spot runs the command %s"
"%s runs the command %s"))
(defun describe-key (key)
"Display documentation of the function invoked by KEY. KEY is a string."
(interactive "kDescribe key: ")
- ;; If this key seq ends with a down event, discard the
- ;; following click or drag event. Otherwise that would
- ;; erase the message.
- (let ((type (aref key (1- (length key)))))
- (if (listp type) (setq type (car type)))
- (and (symbolp type)
- (memq 'down (event-modifiers type))
- (read-event)))
(save-excursion
(let ((modifiers (event-modifiers (aref key 0)))
window position)
(progn
(set-buffer (window-buffer window))
(goto-char position)))
- (let ((defn (key-binding key)))
+ (let ((defn (or (mode-line-key-binding key) (key-binding key))))
(if (or (null defn) (integerp defn))
(message "%s is undefined" (key-description key))
(with-output-to-temp-buffer "*Help*"
(princ " runs the command ")
(prin1 defn)
(princ "\n which is ")
- (describe-function-1 defn nil)
+ (describe-function-1 defn nil (interactive-p))
(print-help-return-message)))))))
(defun describe-mode ()
"Display documentation of current major mode and minor modes.
+The major mode description comes first, followed by the minor modes,
+each on a separate page.
+
For this to work correctly for a minor mode, the mode's indicator variable
\(listed in `minor-mode-alist') must also be a function whose documentation
describes the minor mode."
(interactive)
(with-output-to-temp-buffer "*Help*"
- (let ((minor-modes minor-mode-alist)
- (first t))
+ (when minor-mode-alist
+ (princ "The major mode is described first.
+For minor modes, see following pages.\n\n"))
+ (princ mode-name)
+ (princ " mode:\n")
+ (princ (documentation major-mode))
+ (help-setup-xref (list #'help-xref-mode (current-buffer)) (interactive-p))
+ (let ((minor-modes minor-mode-alist))
(while minor-modes
(let* ((minor-mode (car (car minor-modes)))
(indicator (car (cdr (car minor-modes)))))
(capitalize
(substring (symbol-name minor-mode)
0 (match-beginning 0)))))
- (while (and indicator (symbolp indicator))
+ (while (and indicator (symbolp indicator)
+ (boundp indicator)
+ (not (eq indicator (symbol-value indicator))))
(setq indicator (symbol-value indicator)))
- (if first
- (princ "The minor modes are described first,
-followed by the major mode, which is described on the last page.\n\f\n"))
- (setq first nil)
+ (princ "\n\f\n")
(princ (format "%s minor mode (%s):\n"
pretty-minor-mode
(if indicator
(format "indicator%s" indicator)
"no indicator")))
- (princ (documentation minor-mode))
- (princ "\n\f\n"))))
+ (princ (documentation minor-mode)))))
(setq minor-modes (cdr minor-modes))))
- (princ mode-name)
- (princ " mode:\n")
- (princ (documentation major-mode))
- (help-setup-xref (cons #'help-xref-mode (current-buffer)) (interactive-p))
(print-help-return-message)))
;; So keyboard macro definitions are documented correctly
(defun view-emacs-FAQ ()
"Display the Emacs Frequently Asked Questions (FAQ) file."
(interactive)
- (find-file-read-only (expand-file-name "FAQ" data-directory)))
+;;; (find-file-read-only (expand-file-name "FAQ" data-directory))
+ (info "(emacs-faq)"))
(defun view-lossage ()
"Display last 100 input keystrokes."
(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:
+ "You have typed %THIS-KEY%, 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
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).
+C-i info-lookup-symbol. Display the definition of a specific symbol
+ as found in the manual for the language this buffer is written in.
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 view-lossage. Show 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.
+n view-emacs-news. Display news of recent Emacs changes.
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.
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 ()
+ "Return a function around point or else called by the list containing point.
+If that doesn't give a function, return nil."
(let ((stab (syntax-table)))
(set-syntax-table emacs-lisp-mode-syntax-table)
(unwind-protect
(or (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))
+ (condition-case ()
(save-excursion
(save-restriction
(narrow-to-region (max (point-min) (- (point) 1000)) (point-max))
(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)
+(defvar symbol-file-load-history-loaded nil
+ "Non-nil means we have loaded the file `fns-VERSION.el' in `exec-directory'.
+That file records the part of `load-history' for preloaded files,
+which is cleared out before dumping to make Emacs smaller.")
+
+(defun symbol-file (function)
+ "Return the input source from which FUNCTION was loaded.
+The value is normally a string that was passed to `load':
+either an absolute file name, or a library name
+\(with no directory name and no `.el' or `.elc' at the end).
+It can also be nil, if the definition is not associated with any file."
+ (unless symbol-file-load-history-loaded
+ (load (expand-file-name
+ ;; fns-XX.YY.ZZ.el does not work on DOS filesystem.
+ (if (eq system-type 'ms-dos)
+ "fns.el"
+ (format "fns-%s.el" emacs-version))
+ exec-directory)
+ ;; The file name fns-%s.el already has a .el extension.
+ nil nil t)
+ (setq symbol-file-load-history-loaded t))
(let ((files load-history)
file functions)
(while files
;; 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)
+ (describe-function-1 function nil (interactive-p))
(print-help-return-message)
(save-excursion
(set-buffer standard-output)
(buffer-string)))
(message "You didn't specify a function")))
-(defun describe-function-1 (function parens)
- (let* ((def (symbol-function function))
+(defun describe-function-1 (function parens interactive-p)
+ (let* ((def (if (symbolp function)
+ (symbol-function function)
+ function))
file-name string need-close
(beg (if (commandp def) "an interactive " "a ")))
(setq string
((byte-code-function-p def)
(concat beg "compiled Lisp function"))
((symbolp def)
- (format "alias for `%s'" def))
+ (while (symbolp (symbol-function def))
+ (setq def (symbol-function def)))
+ (format "an alias for `%s'" def))
((eq (car-safe def) 'lambda)
(concat beg "Lisp function"))
((eq (car-safe def) 'macro)
"a mocklisp function")
((eq (car-safe def) 'autoload)
(setq file-name (nth 1 def))
- (format "%s autoloaded Lisp %s"
+ (format "%s autoloaded %s"
(if (commandp def) "an interactive" "an")
- (if (nth 4 def) "macro" "function")
+ (if (eq (nth 4 def) 'keymap) "keymap"
+ (if (nth 4 def) "Lisp macro" "Lisp function"))
))
+ ;; perhaps use keymapp here instead
+ ((eq (car-safe def) 'keymap)
+ (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)))
+ (if is-full
+ "a full keymap"
+ "a sparse keymap")))
(t "")))
(when (and parens (not (equal string "")))
(setq need-close t)
(princ "("))
(princ string)
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (save-match-data
+ (if (re-search-backward "alias for `\\([^`']+\\)'" nil t)
+ (help-xref-button 1 #'describe-function def)))))
(or file-name
- (setq file-name (describe-function-find-file function)))
+ (setq file-name (symbol-file function)))
(if file-name
(progn
(princ " in `")
(help-xref-button 1 #'(lambda (arg)
(let ((location
(find-function-noselect arg)))
- (display-buffer (nth 0 location))
- (goto-char (nth 1 location))))
+ (pop-to-buffer (car location))
+ (goto-char (cdr location))))
function)))))
(if need-close (princ ")"))
(princ ".")
(terpri)
- (let* ((inner-function (if (and (listp def) 'macro)
- (cdr def)
- def))
- (arglist (cond ((byte-code-function-p inner-function)
- (car (append inner-function nil)))
- ((eq (car-safe inner-function) 'lambda)
- (nth 1 inner-function))
- (t t))))
+ ;; 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
+ (princ (cons (if (symbolp function) function "anonymous")
(mapcar (lambda (arg)
(if (memq arg '(&optional &rest))
arg
(if doc
(progn (terpri)
(princ doc)
- (help-setup-xref (cons #'describe-function function) (interactive-p)))
+ (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 ()
+ "Return the bound variable symbol found around point.
+Return 0 if there is no such symbol."
(condition-case ()
(let ((stab (syntax-table)))
(unwind-protect
(terpri)
(let ((doc (documentation-property variable 'variable-documentation)))
(princ (or doc "not documented as a variable.")))
- (help-setup-xref (cons #'describe-variable variable) (interactive-p))
+ (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 only for a custom-type property
+ ;; because those are only present after the var's definition
+ ;; has been loaded.
+ (if (or (get variable 'custom-type) ; after defcustom
+ (get variable 'custom-loads) ; from loaddefs.el
+ (get variable 'standard-value)) ; from cus-start.el
+ (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)
+ ))))
+ ;; Make a hyperlink to the library if appropriate. (Don't
+ ;; change the format of the buffer's initial line in case
+ ;; anything expects the current format.)
+ (let ((file-name (symbol-file variable)))
+ (when file-name
+ (princ "\n\nDefined in `")
+ (princ file-name)
+ (princ "'.")
+ (with-current-buffer "*Help*"
+ (save-excursion
+ (re-search-backward "`\\([^`']+\\)'" nil t)
+ (help-xref-button 1 (lambda (arg)
+ (let ((location
+ (find-variable-noselect arg)))
+ (pop-to-buffer (car location))
+ (goto-char (cdr location))))
+ variable)))))
+
(print-help-return-message)
(save-excursion
(set-buffer standard-output)
(buffer-string))))
(message "You did not specify a variable")))
-(defun describe-bindings (&optional prefix)
+(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."
+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")
- (describe-bindings-internal nil prefix)
+ (or buffer (setq buffer (current-buffer)))
+ (with-current-buffer buffer
+ (describe-bindings-internal nil prefix))
(with-current-buffer "*Help*"
- (setq help-xref-stack nil
- help-xref-stack-item nil)))
+ (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.
+ "Print message listing key sequences that invoke the command DEFINITION.
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
to the specified name LIBRARY.
If the optional third arg PATH is specified, that list of directories
-is used instead of `load-path'."
+is used instead of `load-path'.
+
+When called from a program, the file name is normaly returned as a
+string. When run interactively, the argument INTERACTIVE-CALL is t,
+and the file name is displayed in the echo area."
(interactive (list (read-string "Locate library: ")
nil nil
t))
(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."
+`help-highlight-face'."
:group 'help
:version "20.3"
:type 'boolean)
distinguish references to variables, functions and symbols.")
(defvar help-xref-info-regexp
- "\\<info\\s-+node\\s-`\\([^']+\\)'"
+ "\\<[Ii]nfo[ \t\n]+node[ \t\n]+`\\([^']+\\)'"
"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
+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."
;; The following should probably be abstracted out.
(unwind-protect
(progn
+ ;; Info references
+ (save-excursion
+ (while (re-search-forward help-xref-info-regexp nil t)
+ (let ((data (match-string 1)))
+ (save-match-data
+ (unless (string-match "^([^)]+)" data)
+ (setq data (concat "(emacs)" data))))
+ (help-xref-button 1 #'info data))))
;; Quoted symbols
(save-excursion
(while (re-search-forward help-xref-symbol-regexp nil t)
(and (fboundp sym) ; similarly
(help-xref-button 6 #'describe-function sym)))
((match-string 5)) ; nothing for symbol
- ((and (boundp sym) (fboundp sym))
+ ((or (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)))))
+ (help-xref-button 6 #'help-xref-interned sym)))))))
;; An obvious case of a key substitution:
(save-excursion
- (while (re-search-forward
- "\\<M-x\\s-+\\(\\sw\\(\\sw\\|\\s_\\)+\\)" nil t)
+ (while (re-search-forward
+ ;; Assume command name is only word characters
+ ;; and dashes to get things like `use M-x foo.'.
+ "\\<M-x\\s-+\\(\\sw\\(\\sw\\|-\\)+\\)" 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"
(while
;; Ignore single blank lines in table, but not
;; double ones, which should terminate it.
- (and (looking-at "^\n?[^\n]")
+ (and (not (looking-at "\n\\s-*\n"))
(progn
- (if (and (> (move-to-column col) 0)
- (looking-at "\\(\\sw\\|\\s_\\)+$"))
- ;;
+ (and (eolp) (forward-line))
+ (end-of-line)
+ (skip-chars-backward "^\t\n")
+ (if (and (>= (current-column) col)
+ (looking-at "\\(\\sw\\|-\\)+$"))
(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)))))))
+ (zerop (forward-line)))))))))
(set-syntax-table stab))
;; Make a back-reference in this buffer if appropriate.
(when help-xref-stack
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)))
+ ;; Don't mung properties we've added specially in some instances.
+ (unless (get-text-property (match-beginning match-number) 'help-xref)
+ (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))))
\f
;; Additional functions for (re-)creating types of help buffers.
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 (cons #'help-xref-interned symbol) nil))
+ (let ((fdoc (when (fboundp symbol) (describe-function symbol))))
+ (when (or (boundp symbol) (not fdoc))
+ (describe-variable symbol)
+ ;; We now have a help buffer on the variable. Insert the function
+ ;; text before it.
+ (when fdoc
+ (with-current-buffer "*Help*"
+ (goto-char (point-min))
+ (let ((inhibit-read-only t))
+ (insert fdoc "\n\n" (symbol-name symbol) " is also a variable.\n\n"))
+ (help-setup-xref (list #'help-xref-interned symbol) nil))))))
(defun help-xref-mode (buffer)
"Do a `describe-mode' for the specified BUFFER."
(defun help-follow-mouse (click)
"Follow the cross-reference that you click on."
(interactive "e")
- (save-excursion
- (let* ((start (event-start click))
- (window (car start))
- (pos (car (cdr start))))
- (set-buffer (window-buffer window))
+ (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 method args)
+ "From BUFFER, go back to previous help buffer text using `help-xref-stack'."
+ (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)
- method (car item)
- args (cdr item))
+ position (car item)
+ method (cadr item)
+ args (cddr item))
(setq help-xref-stack (cdr help-xref-stack))))
- (if (listp args)
- (apply method args)
- (funcall method args))))
+ (apply method args)
+ (goto-char position)))
(defun help-go-back ()
+ "Invoke the [back] button (if any) in the Help mode buffer."
(interactive)
(help-follow (1- (point-max))))
For the cross-reference format, see `help-make-xrefs'."
(interactive "d")
- (let* ((help-data (get-text-property pos 'help-xref))
+ (unless pos
+ (setq pos (point)))
+ (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))
+ ;; check if the symbol under point is a function or variable
+ (let ((sym
+ (intern
+ (save-excursion
+ (goto-char pos) (skip-syntax-backward "w_")
+ (buffer-substring (point)
+ (progn (skip-syntax-forward "w_")
+ (point)))))))
+ (when (or (boundp sym) (fboundp sym))
+ (list #'help-xref-interned sym)))))
(method (car help-data))
(args (cdr help-data)))
- (setq help-xref-stack (cons help-xref-stack-item help-xref-stack))
- (setq help-xref-stack-item nil)
(when help-data
+ (setq help-xref-stack (cons (cons (point) help-xref-stack-item)
+ help-xref-stack))
+ (setq help-xref-stack-item nil)
;; There is a reference at point. Follow it.
(apply method args))))
(t ; be circular
(goto-char (point-max)))))))
+\f
+;;; Automatic resizing of temporary buffers.
+
+(defcustom temp-buffer-resize-mode nil
+ "Non-nil means resize windows displaying temporary buffers.
+This makes the window the right height for its contents, but never
+more than `temp-buffer-max-height' nor less than `window-min-height'.
+This applies to `help', `apropos' and `completion' buffers, and some others.
+
+Setting this variable directly does not take effect;
+use either \\[customize] or the function `temp-buffer-resize-mode'."
+ :get (lambda (symbol)
+ (and (memq 'resize-temp-buffer-window temp-buffer-show-hook) t))
+ :set (lambda (symbol value)
+ (temp-buffer-resize-mode (if value 1 -1)))
+ :initialize 'custom-initialize-default
+ :type 'boolean
+ :group 'help
+ :version "20.4")
+
+(defcustom temp-buffer-max-height (lambda (buffer) (/ (- (frame-height) 2) 2))
+ "*Maximum height of a window displaying a temporary buffer.
+This is the maximum height (in text lines) which `resize-temp-buffer-window'
+will give to a window displaying a temporary buffer.
+It can also be a function which will be called with the object corresponding
+to the buffer to be displayed as argument and should return an integer
+positive number."
+ :type '(choice integer function)
+ :group 'help
+ :version "20.4")
+
+(defun temp-buffer-resize-mode (arg)
+ "Toggle the mode which that makes windows smaller for temporary buffers.
+With prefix argument ARG, turn the resizing of windows displaying temporary
+buffers on if ARG is positive or off otherwise.
+See the documentation of the variable `temp-buffer-resize-mode' for
+more information."
+ (interactive "P")
+ (let ((turn-it-on
+ (if (null arg)
+ (not (memq 'resize-temp-buffer-window temp-buffer-show-hook))
+ (> (prefix-numeric-value arg) 0))))
+ (if turn-it-on
+ (progn
+ ;; `help-mode-maybe' may add a `back' button and thus increase the
+ ;; text size, so `resize-temp-buffer-window' must be run *after* it.
+ (add-hook 'temp-buffer-show-hook 'resize-temp-buffer-window 'append)
+ (setq temp-buffer-resize-mode t))
+ (remove-hook 'temp-buffer-show-hook 'resize-temp-buffer-window)
+ (setq temp-buffer-resize-mode nil))))
+
+(defun resize-temp-buffer-window ()
+ "Resize the current window to fit its contents.
+Will not make it higher than `temp-buffer-max-height' nor smaller than
+`window-min-height'. Do nothing if it is the only window on its frame, if it
+is not as wide as the frame or if some of the window's contents are scrolled
+out of view."
+ (unless (or (one-window-p 'nomini)
+ (not (pos-visible-in-window-p (point-min)))
+ (/= (frame-width) (window-width)))
+ (let* ((max-height (if (functionp temp-buffer-max-height)
+ (funcall temp-buffer-max-height (current-buffer))
+ temp-buffer-max-height))
+ (win-height (1- (window-height)))
+ (min-height (1- window-min-height))
+ (text-height (window-buffer-height(selected-window)))
+ (new-height (max (min text-height max-height) min-height)))
+ (enlarge-window (- new-height win-height)))))
+
;;; help.el ends here