;;; help.el --- help commands for Emacs
-;; Copyright (C) 1985-1986, 1993-1994, 1998-2014 Free Software
-;; Foundation, Inc.
+;; Copyright (C) 1985-1986, 1993-1994, 1998-2014 Free Software Foundation, Inc.
-;; Maintainer: FSF
+;; Maintainer: emacs-devel@gnu.org
;; Keywords: help, internal
;; Package: emacs
It computes a message, and applies the optional argument FUNCTION to it.
If FUNCTION is nil, it applies `message', thus displaying the message.
In addition, this function sets up `help-return-method', which see, that
-specifies what to do when the user exits the help buffer."
+specifies what to do when the user exits the help buffer.
+
+Do not call this in the scope of `with-help-window'."
(and (not (get-buffer-window standard-output))
(let ((first-message
(cond ((or
including their special commands.
n Display news of recent Emacs changes.
p TOPIC Find packages matching a given topic keyword.
+P PACKAGE Describe the given Emacs Lisp package.
r Display the Emacs manual in Info mode.
s Display contents of current syntax table, plus explanations.
S SYMBOL Show the section for the given symbol in the on-line manual
(defun view-lossage ()
"Display last 300 input keystrokes.
-To record all your input on a file, use `open-dribble-file'."
+To record all your input, use `open-dribble-file'."
(interactive)
(help-setup-xref (list #'view-lossage)
(called-interactively-p 'interactive))
;; Key bindings
(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.
+ "Display a buffer showing a list of all defined keys, and their definitions.
+The keys are displayed in order of precedence.
The optional argument PREFIX, if non-nil, should be a key sequence;
then we display only bindings that start with that prefix.
(or buffer (setq buffer (current-buffer)))
(help-setup-xref (list #'describe-bindings prefix buffer)
(called-interactively-p 'interactive))
- (with-current-buffer buffer
- (describe-bindings-internal nil prefix)))
+ (with-help-window (help-buffer)
+ ;; Be aware that `describe-buffer-bindings' puts its output into
+ ;; the current buffer.
+ (with-current-buffer (help-buffer)
+ (describe-buffer-bindings buffer prefix))))
;; This function used to be in keymap.c.
(defun describe-bindings-internal (&optional menus prefix)
\(Ordinarily these are omitted from the output.)
The optional argument PREFIX, if non-nil, should be a key sequence;
then we display only bindings that start with that prefix."
+ (declare (obsolete describe-buffer-bindings "24.4"))
(let ((buf (current-buffer)))
(with-help-window (help-buffer)
- (describe-buffer-bindings buf prefix menus))))
+ ;; Be aware that `describe-buffer-bindings' puts its output into
+ ;; the current buffer.
+ (with-current-buffer (help-buffer)
+ (describe-buffer-bindings buf prefix menus)))))
(defun where-is (definition &optional insert)
"Print message listing key sequences that invoke the command DEFINITION.
;; providing the following additional twists:
;; (1) It puts the buffer in `help-mode' (via `help-mode-setup') and
-;; adds cross references (via `help-mode-finish').
+;; adds cross references (via `help-mode-finish').
;; (2) It issues a message telling how to scroll and quit the help
-;; window (via `help-window-setup').
+;; window (via `help-window-setup').
;; (3) An option (customizable via `help-window-select') to select the
-;; help window automatically.
+;; help window automatically.
;; (4) A marker (`help-window-point-marker') to move point in the help
-;; window to an arbitrary buffer position.
-
-;; Note: It's usually always wrong to use `help-print-return-message' in
-;; the body of `with-help-window'.
+;; window to an arbitrary buffer position.
(defmacro with-help-window (buffer-name &rest body)
- "Display buffer with name BUFFER-NAME in a help window evaluating BODY.
-Select help window if the current value of the user option
+ "Display buffer named BUFFER-NAME in a help window.
+Evaluate the forms in BODY with standard output bound to a buffer
+called BUFFER-NAME (creating it if it does not exist), put that
+buffer in `help-mode', display the buffer in a window (see
+`with-temp-buffer-window' for details) and issue a message how to
+deal with that \"help\" window when it's no more needed. Select
+the help window if the current value of the user option
`help-window-select' says so. Return last value in BODY."
(declare (indent 1) (debug t))
`(progn
(if (stringp msg)
(with-output-to-temp-buffer " *Char Help*"
(princ msg)))))
+
+\f
+;; The following functions used to be in help-fns.el, which is not preloaded.
+;; But for various reasons, they are more widely needed, so they were
+;; moved to this file, which is preloaded. http://debbugs.gnu.org/17001
+
+(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 (symbolp def) def "anonymous")
+ (match-string 1 docstring))
+ (unless (zerop (match-beginning 0))
+ (substring docstring 0 (match-beginning 0))))))
+
+(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))))))
+
+(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)))
+
+(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)))
+
\f
(provide 'help)
HCoop / bpt / emacs.git / blobdiff