mirror of
https://git.savannah.gnu.org/git/emacs.git
synced 2024-11-27 07:37:33 +00:00
446 lines
18 KiB
EmacsLisp
446 lines
18 KiB
EmacsLisp
;;; eldoc.el --- show function arglist or variable docstring in echo area
|
||
|
||
;; Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004,
|
||
;; 2005, 2006, 2007 Free Software Foundation, Inc.
|
||
|
||
;; Author: Noah Friedman <friedman@splode.com>
|
||
;; Maintainer: friedman@splode.com
|
||
;; Keywords: extensions
|
||
;; Created: 1995-10-06
|
||
|
||
;; 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, 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; see the file COPYING. If not, write to the
|
||
;; Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
|
||
;; Boston, MA 02110-1301, USA.
|
||
|
||
;;; Commentary:
|
||
|
||
;; This program was inspired by the behavior of the "mouse documentation
|
||
;; window" on many Lisp Machine systems; as you type a function's symbol
|
||
;; name as part of a sexp, it will print the argument list for that
|
||
;; function. Behavior is not identical; for example, you need not actually
|
||
;; type the function name, you need only move point around in a sexp that
|
||
;; calls it. Also, if point is over a documented variable, it will print
|
||
;; the one-line documentation for that variable instead, to remind you of
|
||
;; that variable's meaning.
|
||
|
||
;; One useful way to enable this minor mode is to put the following in your
|
||
;; .emacs:
|
||
;;
|
||
;; (add-hook 'emacs-lisp-mode-hook 'turn-on-eldoc-mode)
|
||
;; (add-hook 'lisp-interaction-mode-hook 'turn-on-eldoc-mode)
|
||
;; (add-hook 'ielm-mode-hook 'turn-on-eldoc-mode)
|
||
|
||
;; Major modes for other languages may use Eldoc by defining an
|
||
;; appropriate function as the buffer-local value of
|
||
;; `eldoc-documentation-function'.
|
||
|
||
;;; Code:
|
||
|
||
(require 'help-fns) ;For fundoc-usage handling functions.
|
||
|
||
(defgroup eldoc nil
|
||
"Show function arglist or variable docstring in echo area."
|
||
:group 'lisp
|
||
:group 'extensions)
|
||
|
||
(defcustom eldoc-idle-delay 0.50
|
||
"*Number of seconds of idle time to wait before printing.
|
||
If user input arrives before this interval of time has elapsed after the
|
||
last input, no documentation will be printed.
|
||
|
||
If this variable is set to 0, no idle time is required."
|
||
:type 'number
|
||
:group 'eldoc)
|
||
|
||
;;;###autoload
|
||
(defcustom eldoc-minor-mode-string " ElDoc"
|
||
"*String to display in mode line when Eldoc Mode is enabled; nil for none."
|
||
:type '(choice string (const :tag "None" nil))
|
||
:group 'eldoc)
|
||
|
||
(defcustom eldoc-argument-case 'upcase
|
||
"Case to display argument names of functions, as a symbol.
|
||
This has two preferred values: `upcase' or `downcase'.
|
||
Actually, any name of a function which takes a string as an argument and
|
||
returns another string is acceptable."
|
||
:type '(radio (function-item upcase)
|
||
(function-item downcase)
|
||
function)
|
||
:group 'eldoc)
|
||
|
||
(defcustom eldoc-echo-area-use-multiline-p 'truncate-sym-name-if-fit
|
||
"*Allow long eldoc messages to resize echo area display.
|
||
If value is t, never attempt to truncate messages; complete symbol name
|
||
and function arglist or 1-line variable documentation will be displayed
|
||
even if echo area must be resized to fit.
|
||
|
||
If value is any non-nil value other than t, symbol name may be truncated
|
||
if it will enable the function arglist or documentation string to fit on a
|
||
single line without resizing window. Otherwise, behavior is just like
|
||
former case.
|
||
|
||
If value is nil, messages are always truncated to fit in a single line of
|
||
display in the echo area. Function or variable symbol name may be
|
||
truncated to make more of the arglist or documentation string visible."
|
||
:type '(radio (const :tag "Always" t)
|
||
(const :tag "Never" nil)
|
||
(const :tag "Yes, but truncate symbol names if it will\
|
||
enable argument list to fit on one line" truncate-sym-name-if-fit))
|
||
:group 'eldoc)
|
||
|
||
;;; No user options below here.
|
||
|
||
(defvar eldoc-message-commands-table-size 31
|
||
"This is used by eldoc-add-command to initialize eldoc-message-commands
|
||
as an obarray.
|
||
It should probably never be necessary to do so, but if you
|
||
choose to increase the number of buckets, you must do so before loading
|
||
this file since the obarray is initialized at load time.
|
||
Remember to keep it a prime number to improve hash performance.")
|
||
|
||
(defconst eldoc-message-commands
|
||
(make-vector eldoc-message-commands-table-size 0)
|
||
"Commands after which it is appropriate to print in the echo area.
|
||
Eldoc does not try to print function arglists, etc. after just any command,
|
||
because some commands print their own messages in the echo area and these
|
||
functions would instantly overwrite them. But self-insert-command as well
|
||
as most motion commands are good candidates.
|
||
This variable contains an obarray of symbols; do not manipulate it
|
||
directly. Instead, use `eldoc-add-command' and `eldoc-remove-command'.")
|
||
|
||
(defconst eldoc-last-data (make-vector 3 nil)
|
||
"Bookkeeping; elements are as follows:
|
||
0 - contains the last symbol read from the buffer.
|
||
1 - contains the string last displayed in the echo area for that
|
||
symbol, so it can be printed again if necessary without reconsing.
|
||
2 - 'function if function args, 'variable if variable documentation.")
|
||
(defvar eldoc-last-message nil)
|
||
|
||
(defvar eldoc-timer nil "eldoc's timer object.")
|
||
|
||
(defvar eldoc-current-idle-delay eldoc-idle-delay
|
||
"idle time delay currently in use by timer.
|
||
This is used to determine if `eldoc-idle-delay' is changed by the user.")
|
||
|
||
|
||
;;;###autoload
|
||
(define-minor-mode eldoc-mode
|
||
"Toggle ElDoc mode on or off.
|
||
In ElDoc mode, the echo area displays information about a
|
||
function or variable in the text where point is. If point is
|
||
on a documented variable, it displays the first line of that
|
||
variable's doc string. Otherwise it displays the argument list
|
||
of the function called in the expression point is on.
|
||
|
||
With prefix ARG, turn ElDoc mode on if and only if ARG is positive."
|
||
:group 'eldoc :lighter eldoc-minor-mode-string
|
||
(setq eldoc-last-message nil)
|
||
(if eldoc-mode
|
||
(progn
|
||
(add-hook 'post-command-hook 'eldoc-schedule-timer nil t)
|
||
(add-hook 'pre-command-hook 'eldoc-pre-command-refresh-echo-area t))
|
||
(remove-hook 'post-command-hook 'eldoc-schedule-timer)
|
||
(remove-hook 'pre-command-hook 'eldoc-pre-command-refresh-echo-area)))
|
||
|
||
;;;###autoload
|
||
(defun turn-on-eldoc-mode ()
|
||
"Unequivocally turn on ElDoc mode (see command `eldoc-mode')."
|
||
(interactive)
|
||
(eldoc-mode 1))
|
||
|
||
|
||
(defun eldoc-schedule-timer ()
|
||
(or (and eldoc-timer
|
||
(memq eldoc-timer timer-idle-list))
|
||
(setq eldoc-timer
|
||
(run-with-idle-timer eldoc-idle-delay t
|
||
'eldoc-print-current-symbol-info)))
|
||
|
||
;; If user has changed the idle delay, update the timer.
|
||
(cond ((not (= eldoc-idle-delay eldoc-current-idle-delay))
|
||
(setq eldoc-current-idle-delay eldoc-idle-delay)
|
||
(timer-set-idle-time eldoc-timer eldoc-idle-delay t))))
|
||
|
||
(defun eldoc-message (&rest args)
|
||
(let ((omessage eldoc-last-message))
|
||
(setq eldoc-last-message
|
||
(cond ((eq (car args) eldoc-last-message) eldoc-last-message)
|
||
((null (car args)) nil)
|
||
;; If only one arg, no formatting to do, so put it in
|
||
;; eldoc-last-message so eq test above might succeed on
|
||
;; subsequent calls.
|
||
((null (cdr args)) (car args))
|
||
(t (apply 'format args))))
|
||
;; In emacs 19.29 and later, and XEmacs 19.13 and later, all messages
|
||
;; are recorded in a log. Do not put eldoc messages in that log since
|
||
;; they are Legion.
|
||
;; Emacs way of preventing log messages.
|
||
(let ((message-log-max nil))
|
||
(cond (eldoc-last-message (message "%s" eldoc-last-message))
|
||
(omessage (message nil)))))
|
||
eldoc-last-message)
|
||
|
||
;; This function goes on pre-command-hook for XEmacs or when using idle
|
||
;; timers in Emacs. Motion commands clear the echo area for some reason,
|
||
;; which make eldoc messages flicker or disappear just before motion
|
||
;; begins. This function reprints the last eldoc message immediately
|
||
;; before the next command executes, which does away with the flicker.
|
||
;; This doesn't seem to be required for Emacs 19.28 and earlier.
|
||
(defun eldoc-pre-command-refresh-echo-area ()
|
||
(and eldoc-last-message
|
||
(if (eldoc-display-message-no-interference-p)
|
||
(eldoc-message eldoc-last-message)
|
||
(setq eldoc-last-message nil))))
|
||
|
||
;; Decide whether now is a good time to display a message.
|
||
(defun eldoc-display-message-p ()
|
||
(and (eldoc-display-message-no-interference-p)
|
||
;; If this-command is non-nil while running via an idle
|
||
;; timer, we're still in the middle of executing a command,
|
||
;; e.g. a query-replace where it would be annoying to
|
||
;; overwrite the echo area.
|
||
(and (not this-command)
|
||
(symbolp last-command)
|
||
(intern-soft (symbol-name last-command)
|
||
eldoc-message-commands))))
|
||
|
||
;; Check various conditions about the current environment that might make
|
||
;; it undesirable to print eldoc messages right this instant.
|
||
(defun eldoc-display-message-no-interference-p ()
|
||
(and eldoc-mode
|
||
(not executing-kbd-macro)
|
||
(not (and (boundp 'edebug-active) edebug-active))
|
||
;; Having this mode operate in an active minibuffer/echo area causes
|
||
;; interference with what's going on there.
|
||
(not cursor-in-echo-area)
|
||
(not (eq (selected-window) (minibuffer-window)))))
|
||
|
||
|
||
;;;###autoload
|
||
(defvar eldoc-documentation-function nil
|
||
"If non-nil, function to call to return doc string.
|
||
The function of no args should return a one-line string for displaying
|
||
doc about a function etc. appropriate to the context around point.
|
||
It should return nil if there's no doc appropriate for the context.
|
||
Typically doc is returned if point is on a function-like name or in its
|
||
arg list.
|
||
|
||
This variable is expected to be made buffer-local by modes (other than
|
||
Emacs Lisp mode) that support Eldoc.")
|
||
|
||
(defun eldoc-print-current-symbol-info ()
|
||
(condition-case err
|
||
(and (eldoc-display-message-p)
|
||
(if eldoc-documentation-function
|
||
(eldoc-message (funcall eldoc-documentation-function))
|
||
(let* ((current-symbol (eldoc-current-symbol))
|
||
(current-fnsym (eldoc-fnsym-in-current-sexp))
|
||
(doc (cond
|
||
((eq current-symbol current-fnsym)
|
||
(or (eldoc-get-fnsym-args-string current-fnsym)
|
||
(eldoc-get-var-docstring current-symbol)))
|
||
(t
|
||
(or (eldoc-get-var-docstring current-symbol)
|
||
(eldoc-get-fnsym-args-string current-fnsym))))))
|
||
(eldoc-message doc))))
|
||
;; This is run from post-command-hook or some idle timer thing,
|
||
;; so we need to be careful that errors aren't ignored.
|
||
(error (message "eldoc error: %s" err))))
|
||
|
||
;; Return a string containing the function parameter list, or 1-line
|
||
;; docstring if function is a subr and no arglist is obtainable from the
|
||
;; docstring or elsewhere.
|
||
(defun eldoc-get-fnsym-args-string (sym)
|
||
(let ((args nil)
|
||
(doc nil))
|
||
(cond ((not (and sym (symbolp sym) (fboundp sym))))
|
||
((and (eq sym (aref eldoc-last-data 0))
|
||
(eq 'function (aref eldoc-last-data 2)))
|
||
(setq doc (aref eldoc-last-data 1)))
|
||
((setq doc (help-split-fundoc (documentation sym t) sym))
|
||
(setq args (car doc))
|
||
(string-match "\\`[^ )]* ?" args)
|
||
(setq args (concat "(" (substring args (match-end 0)))))
|
||
(t
|
||
(setq args (eldoc-function-argstring sym))))
|
||
(cond (args
|
||
(setq doc (eldoc-docstring-format-sym-doc sym args))
|
||
(eldoc-last-data-store sym doc 'function)))
|
||
doc))
|
||
|
||
;; Return a string containing a brief (one-line) documentation string for
|
||
;; the variable.
|
||
(defun eldoc-get-var-docstring (sym)
|
||
(when sym
|
||
(cond ((and (eq sym (aref eldoc-last-data 0))
|
||
(eq 'variable (aref eldoc-last-data 2)))
|
||
(aref eldoc-last-data 1))
|
||
(t
|
||
(let ((doc (documentation-property sym 'variable-documentation t)))
|
||
(cond (doc
|
||
(setq doc (eldoc-docstring-format-sym-doc
|
||
sym (eldoc-docstring-first-line doc)))
|
||
(eldoc-last-data-store sym doc 'variable)))
|
||
doc)))))
|
||
|
||
(defun eldoc-last-data-store (symbol doc type)
|
||
(aset eldoc-last-data 0 symbol)
|
||
(aset eldoc-last-data 1 doc)
|
||
(aset eldoc-last-data 2 type))
|
||
|
||
;; Note that any leading `*' in the docstring (which indicates the variable
|
||
;; is a user option) is removed.
|
||
(defun eldoc-docstring-first-line (doc)
|
||
(and (stringp doc)
|
||
(substitute-command-keys
|
||
(save-match-data
|
||
(let ((start (if (string-match "^\\*" doc) (match-end 0) 0)))
|
||
(cond ((string-match "\n" doc)
|
||
(substring doc start (match-beginning 0)))
|
||
((zerop start) doc)
|
||
(t (substring doc start))))))))
|
||
|
||
;; If the entire line cannot fit in the echo area, the symbol name may be
|
||
;; truncated or eliminated entirely from the output to make room for the
|
||
;; description.
|
||
(defun eldoc-docstring-format-sym-doc (sym doc)
|
||
(save-match-data
|
||
(let* ((name (symbol-name sym))
|
||
(ea-multi eldoc-echo-area-use-multiline-p)
|
||
;; Subtract 1 from window width since emacs will not write
|
||
;; any chars to the last column, or in later versions, will
|
||
;; cause a wraparound and resize of the echo area.
|
||
(ea-width (1- (window-width (minibuffer-window))))
|
||
(strip (- (+ (length name) (length ": ") (length doc)) ea-width)))
|
||
(cond ((or (<= strip 0)
|
||
(eq ea-multi t)
|
||
(and ea-multi (> (length doc) ea-width)))
|
||
(format "%s: %s" sym doc))
|
||
((> (length doc) ea-width)
|
||
(substring (format "%s" doc) 0 ea-width))
|
||
((>= strip (length name))
|
||
(format "%s" doc))
|
||
(t
|
||
;; Show the end of the partial symbol name, rather
|
||
;; than the beginning, since the former is more likely
|
||
;; to be unique given package namespace conventions.
|
||
(setq name (substring name strip))
|
||
(format "%s: %s" name doc))))))
|
||
|
||
|
||
(defun eldoc-fnsym-in-current-sexp ()
|
||
(let ((p (point)))
|
||
(eldoc-beginning-of-sexp)
|
||
(prog1
|
||
;; Don't do anything if current word is inside a string.
|
||
(if (= (or (char-after (1- (point))) 0) ?\")
|
||
nil
|
||
(eldoc-current-symbol))
|
||
(goto-char p))))
|
||
|
||
(defun eldoc-beginning-of-sexp ()
|
||
(let ((parse-sexp-ignore-comments t))
|
||
(condition-case err
|
||
(while (progn
|
||
(forward-sexp -1)
|
||
(or (= (char-before) ?\")
|
||
(> (point) (point-min)))))
|
||
(error nil))))
|
||
|
||
;; returns nil unless current word is an interned symbol.
|
||
(defun eldoc-current-symbol ()
|
||
(let ((c (char-after (point))))
|
||
(and c
|
||
(memq (char-syntax c) '(?w ?_))
|
||
(intern-soft (current-word)))))
|
||
|
||
;; Do indirect function resolution if possible.
|
||
(defun eldoc-symbol-function (fsym)
|
||
(let ((defn (and (fboundp fsym)
|
||
(symbol-function fsym))))
|
||
(and (symbolp defn)
|
||
(condition-case err
|
||
(setq defn (indirect-function fsym))
|
||
(error (setq defn nil))))
|
||
defn))
|
||
|
||
(defun eldoc-function-argstring (fn)
|
||
(eldoc-function-argstring-format (help-function-arglist fn)))
|
||
|
||
(defun eldoc-function-argstring-format (arglist)
|
||
(cond ((not (listp arglist))
|
||
(setq arglist nil))
|
||
((symbolp (car arglist))
|
||
(setq arglist
|
||
(mapcar (function (lambda (s)
|
||
(if (memq s '(&optional &rest))
|
||
(symbol-name s)
|
||
(funcall eldoc-argument-case
|
||
(symbol-name s)))))
|
||
arglist)))
|
||
((stringp (car arglist))
|
||
(setq arglist
|
||
(mapcar (function (lambda (s)
|
||
(if (member s '("&optional" "&rest"))
|
||
s
|
||
(funcall eldoc-argument-case s))))
|
||
arglist))))
|
||
(concat "(" (mapconcat 'identity arglist " ") ")"))
|
||
|
||
|
||
;; When point is in a sexp, the function args are not reprinted in the echo
|
||
;; area after every possible interactive command because some of them print
|
||
;; their own messages in the echo area; the eldoc functions would instantly
|
||
;; overwrite them unless it is more restrained.
|
||
;; These functions do display-command table management.
|
||
|
||
(defun eldoc-add-command (&rest cmds)
|
||
(dolist (name cmds)
|
||
(and (symbolp name)
|
||
(setq name (symbol-name name)))
|
||
(set (intern name eldoc-message-commands) t)))
|
||
|
||
(defun eldoc-add-command-completions (&rest names)
|
||
(dolist (name names)
|
||
(apply 'eldoc-add-command (all-completions name obarray 'commandp))))
|
||
|
||
(defun eldoc-remove-command (&rest cmds)
|
||
(dolist (name cmds)
|
||
(and (symbolp name)
|
||
(setq name (symbol-name name)))
|
||
(unintern name eldoc-message-commands)))
|
||
|
||
(defun eldoc-remove-command-completions (&rest names)
|
||
(dolist (name names)
|
||
(apply 'eldoc-remove-command
|
||
(all-completions name eldoc-message-commands))))
|
||
|
||
|
||
;; Prime the command list.
|
||
(eldoc-add-command-completions
|
||
"backward-" "beginning-of-" "move-beginning-of-" "delete-other-windows"
|
||
"delete-window" "handle-select-window"
|
||
"end-of-" "move-end-of-" "exchange-point-and-mark" "forward-"
|
||
"indent-for-tab-command" "goto-" "mark-page" "mark-paragraph"
|
||
"mouse-set-point" "move-" "pop-global-mark" "next-" "other-window"
|
||
"previous-" "recenter" "scroll-" "self-insert-command"
|
||
"split-window-" "up-list" "down-list")
|
||
|
||
(provide 'eldoc)
|
||
|
||
;; arch-tag: c9a58f9d-2055-46c1-9b82-7248b71a8375
|
||
;;; eldoc.el ends here
|