(require 'help-fns)
(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)
(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)
(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.")
(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)))
(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)))
(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)
((null (cdr args)) (car args))
(t (apply 'format args))))
(let ((message-log-max nil))
(cond (eldoc-last-message (message "%s" eldoc-last-message))
(omessage (message nil)))))
eldoc-last-message)
(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))))
(defun eldoc-display-message-p ()
(and (eldoc-display-message-no-interference-p)
(and (not this-command)
(symbolp last-command)
(intern-soft (symbol-name last-command)
eldoc-message-commands))))
(defun eldoc-display-message-no-interference-p ()
(and eldoc-mode
(not executing-kbd-macro)
(not (and (boundp 'edebug-active) edebug-active))
(not cursor-in-echo-area)
(not (eq (selected-window) (minibuffer-window)))))
(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))))
(error (message "eldoc error: %s" err))))
(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))
(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))
(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))))))))
(defun eldoc-docstring-format-sym-doc (sym doc)
(save-match-data
(let* ((name (symbol-name sym))
(ea-multi eldoc-echo-area-use-multiline-p)
(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
(setq name (substring name strip))
(format "%s: %s" name doc))))))
(defun eldoc-fnsym-in-current-sexp ()
(let ((p (point)))
(eldoc-beginning-of-sexp)
(prog1
(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