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-rw-r--r--lisp/emacs-lisp/eldoc.el541
1 files changed, 420 insertions, 121 deletions
diff --git a/lisp/emacs-lisp/eldoc.el b/lisp/emacs-lisp/eldoc.el
index ef5dbf8103f..6ed5bff9f44 100644
--- a/lisp/emacs-lisp/eldoc.el
+++ b/lisp/emacs-lisp/eldoc.el
@@ -5,7 +5,7 @@
;; Author: Noah Friedman <friedman@splode.com>
;; Keywords: extensions
;; Created: 1995-10-06
-;; Version: 1.0.0
+;; Version: 1.5.0
;; Package-Requires: ((emacs "26.3"))
;; This is a GNU ELPA :core package. Avoid functionality that is not
@@ -47,6 +47,8 @@
;;; Code:
+(eval-when-compile (require 'cl-lib))
+
(defgroup eldoc nil
"Show function arglist or variable docstring in echo area."
:group 'lisp
@@ -77,38 +79,50 @@ Actually, any name of a function which takes a string as an argument and
returns another string is acceptable.
Note that this variable has no effect, unless
-`eldoc-documentation-function' handles it explicitly."
+`eldoc-documentation-strategy' handles it explicitly."
:type '(radio (function-item upcase)
(function-item downcase)
function))
(make-obsolete-variable 'eldoc-argument-case nil "25.1")
(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.
-
-Note that this variable has no effect, unless
-`eldoc-documentation-function' handles it explicitly."
- :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)))
+ "Allow long ElDoc doc strings to resize echo area display.
+If value is t, never attempt to truncate messages, even if the
+echo area must be resized to fit.
+
+If value is a number (integer or floating point), it has the
+semantics of `max-mini-window-height', constraining the resizing
+for ElDoc purposes only.
+
+Any resizing respects `max-mini-window-height'.
+
+If value is any non-nil symbol other than t, the part of the doc
+string that represents the symbol's name may be truncated if it
+will enable the rest of the doc string to fit on a single line,
+without resizing the echo area.
+
+If value is nil, a doc string is always truncated to fit in a
+single line of display in the echo area."
+ :type '(radio (const :tag "Always" t)
+ (float :tag "Fraction of frame height" 0.25)
+ (integer :tag "Number of lines" 5)
+ (const :tag "Never" nil)
+ (const :tag "Yes, but ask major-mode to truncate
+ symbol names if it will\ enable argument list to fit on one
+ line" truncate-sym-name-if-fit)))
+
+(defcustom eldoc-prefer-doc-buffer nil
+ "Prefer ElDoc's documentation buffer if it is showing in some frame.
+If this variable's value is t and a piece of documentation needs
+to be truncated to fit in the echo area, do so if ElDoc's
+documentation buffer is not already showing, since the buffer
+always holds the full documentation."
+ :type 'boolean)
(defface eldoc-highlight-function-argument
'((t (:inherit bold)))
"Face used for the argument at point in a function's argument list.
-Note that this face has no effect unless the `eldoc-documentation-function'
+Note that this face has no effect unless the `eldoc-documentation-strategy'
handles it explicitly.")
;;; No user options below here.
@@ -150,7 +164,7 @@ directly. Instead, use `eldoc-add-command' and `eldoc-remove-command'.")
This is used to determine if `eldoc-idle-delay' is changed by the user.")
(defvar eldoc-message-function #'eldoc-minibuffer-message
- "The function used by `eldoc-message' to display messages.
+ "The function used by `eldoc--message' to display messages.
It should receive the same arguments as `message'.")
(defun eldoc-edit-message-commands ()
@@ -203,7 +217,7 @@ expression point is on." :lighter eldoc-minor-mode-string
:init-value t
;; For `read--expression', the usual global mode mechanism of
;; `change-major-mode-hook' runs in the minibuffer before
- ;; `eldoc-documentation-function' is set, so `turn-on-eldoc-mode'
+ ;; `eldoc-documentation-strategy' is set, so `turn-on-eldoc-mode'
;; does nothing. Configure and enable eldoc from
;; `eval-expression-minibuffer-setup-hook' instead.
(if global-eldoc-mode
@@ -216,13 +230,16 @@ expression point is on." :lighter eldoc-minor-mode-string
;; Setup `eldoc', similar to `emacs-lisp-mode'. FIXME: Call
;; `emacs-lisp-mode' itself?
(add-hook 'eldoc-documentation-functions
- #'elisp-eldoc-documentation-function nil t)
+ #'elisp-eldoc-var-docstring nil t)
+ (add-hook 'eldoc-documentation-functions
+ #'elisp-eldoc-funcall nil t)
+ (setq eldoc-documentation-strategy 'eldoc-documentation-default)
(eldoc-mode +1))
;;;###autoload
(defun turn-on-eldoc-mode ()
"Turn on `eldoc-mode' if the buffer has ElDoc support enabled.
-See `eldoc-documentation-function' for more detail."
+See `eldoc-documentation-strategy' for more detail."
(when (eldoc--supported-p)
(eldoc-mode 1)))
@@ -241,7 +258,9 @@ reflect the change."
(when (or eldoc-mode
(and global-eldoc-mode
(eldoc--supported-p)))
- (eldoc-print-current-symbol-info))))))
+ ;; Don't ignore, but also don't full-on signal errors
+ (with-demoted-errors "eldoc error: %s"
+ (eldoc-print-current-symbol-info)) )))))
;; If user has changed the idle delay, update the timer.
(cond ((not (= eldoc-idle-delay eldoc-current-idle-delay))
@@ -279,7 +298,10 @@ Otherwise work like `message'."
(force-mode-line-update)))
(apply #'message format-string args)))
-(defun eldoc-message (&optional string)
+(make-obsolete
+ 'eldoc-message "use `eldoc-documentation-functions' instead." "eldoc-1.1.0")
+(defun eldoc-message (&optional string) (eldoc--message string))
+(defun eldoc--message (&optional string)
"Display STRING as an ElDoc message if it's non-nil.
Also store it in `eldoc-last-message' and return that value."
@@ -313,8 +335,8 @@ Also store it in `eldoc-last-message' and return that value."
(not (minibufferp)) ;We don't use the echo area when in minibuffer.
(if (and (eldoc-display-message-no-interference-p)
(eldoc--message-command-p this-command))
- (eldoc-message eldoc-last-message)
- ;; No need to call eldoc-message since the echo area will be cleared
+ (eldoc--message eldoc-last-message)
+ ;; No need to call eldoc--message since the echo area will be cleared
;; for us, but do note that the last-message will be gone.
(setq eldoc-last-message nil))))
@@ -338,12 +360,39 @@ Also store it in `eldoc-last-message' and return that value."
(defvar eldoc-documentation-functions nil
- "Hook for functions to call to return doc string.
-Each function should accept no arguments and 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.
+ "Hook of functions that produce doc strings.
+
+A doc string is typically relevant if point is on a function-like
+name, inside its arg list, or on any object with some associated
+information.
+
+Each hook function is called with at least one argument CALLBACK,
+a function, and decides whether to display a doc short string
+about the context around point.
+
+- If that decision can be taken quickly, the hook function may
+ call CALLBACK immediately following the protocol described
+ below. Alternatively it may ignore CALLBACK entirely and
+ return either the doc string, or nil if there's no doc
+ appropriate for the context.
+
+- If the computation of said doc string (or the decision whether
+ there is one at all) is expensive or can't be performed
+ directly, the hook function should return a non-nil, non-string
+ value and arrange for CALLBACK to be called at a later time,
+ using asynchronous processes or other asynchronous mechanisms.
+
+To call the CALLBACK function, the hook function must pass it an
+obligatory argument DOCSTRING, a string containing the
+documentation, followed by an optional list of keyword-value
+pairs of the form (:KEY VALUE :KEY2 VALUE2...). KEY can be:
+
+* `:thing', VALUE is a short string or symbol designating what is
+ being reported on. The documentation display engine can elect
+ to remove this information depending on space contraints;
+
+* `:face', VALUE is a symbol designating a face to use when
+ displaying `:thing''s value.
Major modes should modify this hook locally, for example:
(add-hook \\='eldoc-documentation-functions #\\='foo-mode-eldoc nil t)
@@ -351,110 +400,360 @@ so that the global value (i.e. the default value of the hook) is
taken into account if the major mode specific function does not
return any documentation.")
+(defvar eldoc--doc-buffer nil "Buffer holding latest eldoc-produced docs.")
+(defun eldoc-doc-buffer (&optional interactive)
+ "Get latest *eldoc* help buffer. Interactively, display it."
+ (interactive (list t))
+ (prog1
+ (if (and eldoc--doc-buffer (buffer-live-p eldoc--doc-buffer))
+ eldoc--doc-buffer
+ (setq eldoc--doc-buffer (get-buffer-create "*eldoc*")))
+ (when interactive (display-buffer eldoc--doc-buffer))))
+
+(defun eldoc--handle-docs (docs)
+ "Display multiple DOCS in echo area.
+DOCS is a list of (STRING PLIST...). It is already sorted.
+Honor most of `eldoc-echo-area-use-multiline-p'."
+ ;; If there's nothing to report clear the echo area, but don't erase
+ ;; the last *eldoc* buffer.
+ (if (null docs) (eldoc--message nil)
+ (let*
+ ;; Otherwise, establish some parameters.
+ ((width (1- (window-width (minibuffer-window))))
+ (val (if (and (symbolp eldoc-echo-area-use-multiline-p)
+ eldoc-echo-area-use-multiline-p)
+ max-mini-window-height
+ eldoc-echo-area-use-multiline-p))
+ (available (cl-typecase val
+ (float (truncate (* (frame-height) val)))
+ (integer val)
+ (t 1)))
+ (things-reported-on)
+ single-doc single-doc-sym)
+ ;; Then, compose the contents of the `*eldoc*' buffer.
+ (with-current-buffer (eldoc-doc-buffer)
+ (let ((inhibit-read-only t))
+ (erase-buffer) (setq buffer-read-only t)
+ (local-set-key "q" 'quit-window)
+ (cl-loop for (docs . rest) on docs
+ for (this-doc . plist) = docs
+ for thing = (plist-get plist :thing)
+ when thing do
+ (cl-pushnew thing things-reported-on)
+ (setq this-doc
+ (concat
+ (propertize (format "%s" thing)
+ 'face (plist-get plist :face))
+ ": "
+ this-doc))
+ do (insert this-doc)
+ when rest do (insert "\n")))
+ ;; Rename the buffer.
+ (when things-reported-on
+ (rename-buffer (format "*eldoc for %s*"
+ (mapconcat (lambda (s) (format "%s" s))
+ things-reported-on
+ ", ")))))
+ ;; Finally, output to the echo area. I'm pretty sure nicer
+ ;; strategies can be used here, probably by splitting this
+ ;; function into some `eldoc-display-functions' special hook.
+ (let ((echo-area-message
+ (cond
+ (;; We handle the `truncate-sym-name-if-fit' special
+ ;; case first, by checking if for a lot of special
+ ;; conditions.
+ (and
+ (eq 'truncate-sym-name-if-fit eldoc-echo-area-use-multiline-p)
+ (null (cdr docs))
+ (setq single-doc (caar docs))
+ (setq single-doc-sym
+ (format "%s" (plist-get (cdar docs) :thing)))
+ (< (length single-doc) width)
+ (not (string-match "\n" single-doc))
+ (> (+ (length single-doc) (length single-doc-sym) 2) width))
+ single-doc)
+ ((> available 1)
+ (with-current-buffer (eldoc-doc-buffer)
+ (cl-loop
+ initially
+ (goto-char (point-min))
+ (goto-char (line-end-position (1+ available)))
+ for truncated = nil then t
+ for needed
+ = (let ((truncate-lines message-truncate-lines))
+ (count-screen-lines (point-min) (point) t
+ (minibuffer-window)))
+ while (> needed (if truncated (1- available) available))
+ do (goto-char (line-end-position (if truncated 0 -1)))
+ (while (and (not (bobp)) (bolp)) (goto-char (line-end-position 0)))
+ finally
+ (unless (and truncated
+ eldoc-prefer-doc-buffer
+ (get-buffer-window eldoc--doc-buffer))
+ (cl-return
+ (concat
+ (buffer-substring (point-min) (point))
+ (and truncated
+ (format
+ "\n(Documentation truncated. Use `%s' to see rest)"
+ (substitute-command-keys "\\[eldoc-doc-buffer]")))))))))
+ ((= available 1)
+ ;; Truncate "brutally." ; FIXME: use `eldoc-prefer-doc-buffer' too?
+ (with-current-buffer (eldoc-doc-buffer)
+ (truncate-string-to-width
+ (buffer-substring (goto-char (point-min)) (line-end-position 1)) width))))))
+ (when echo-area-message
+ (eldoc--message echo-area-message))))))
+
(defun eldoc-documentation-default ()
"Show first doc string for item at point.
-Default value for `eldoc-documentation-function'."
- (let ((res (run-hook-with-args-until-success 'eldoc-documentation-functions)))
- (when res
- (if eldoc-echo-area-use-multiline-p res
- (truncate-string-to-width
- res (1- (window-width (minibuffer-window))))))))
+Default value for `eldoc-documentation-strategy'."
+ (run-hook-with-args-until-success 'eldoc-documentation-functions
+ (eldoc--make-callback :patient)))
+
+(defun eldoc--documentation-compose-1 (eagerlyp)
+ "Helper function for composing multiple doc strings.
+If EAGERLYP is non-nil show documentation as soon as possible,
+else wait for all doc strings."
+ (run-hook-wrapped 'eldoc-documentation-functions
+ (lambda (f)
+ (let* ((callback (eldoc--make-callback
+ (if eagerlyp :eager :patient)))
+ (str (funcall f callback)))
+ (if (or (null str) (stringp str)) (funcall callback str))
+ nil)))
+ t)
(defun eldoc-documentation-compose ()
- "Show multiple doc string results at once.
-Meant as a value for `eldoc-documentation-function'."
- (let (res)
- (run-hook-wrapped
- 'eldoc-documentation-functions
- (lambda (f)
- (let ((str (funcall f)))
- (when str (push str res))
- nil)))
- (when res
- (setq res (mapconcat #'identity (nreverse res) ", "))
- (if eldoc-echo-area-use-multiline-p res
- (truncate-string-to-width
- res (1- (window-width (minibuffer-window))))))))
-
-(defcustom eldoc-documentation-function #'eldoc-documentation-default
- "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.
-
-The result is used as is, so the function must explicitly handle
-the variables `eldoc-argument-case' and `eldoc-echo-area-use-multiline-p',
-and the face `eldoc-highlight-function-argument', if they are to have any
-effect."
+ "Show multiple doc strings at once after waiting for all.
+Meant as a value for `eldoc-documentation-strategy'."
+ (eldoc--documentation-compose-1 nil))
+
+(defun eldoc-documentation-compose-eagerly ()
+ "Show multiple doc strings at once as soon as possible.
+Meant as a value for `eldoc-documentation-strategy'."
+ (eldoc--documentation-compose-1 t))
+
+(defun eldoc-documentation-enthusiast ()
+ "Show most important doc string produced so far.
+Meant as a value for `eldoc-documentation-strategy'."
+ (run-hook-wrapped 'eldoc-documentation-functions
+ (lambda (f)
+ (let* ((callback (eldoc--make-callback :enthusiast))
+ (str (funcall f callback)))
+ (if (stringp str) (funcall callback str))
+ nil))))
+
+;; JT@2020-07-10: ElDoc is pre-loaded, so in Emacs < 28 we can't
+;; make the "old" `eldoc-documentation-function' point to the new
+;; `eldoc-documentation-strategy', so we do the reverse. This allows
+;; for ElDoc to be loaded in those older Emacs versions and work with
+;; whomever (major-modes, extensions, user) sets one or the other
+;; variable.
+(defmacro eldoc--documentation-strategy-defcustom
+ (main secondary value docstring &rest more)
+ "Defcustom helper macro for sorting `eldoc-documentation-strategy'."
+ (declare (indent 2))
+ `(if (< emacs-major-version 28)
+ (progn
+ (defcustom ,secondary ,value ,docstring ,@more)
+ (define-obsolete-variable-alias ',main ',secondary "eldoc-1.1.0"))
+ (progn
+ (defcustom ,main ,value ,docstring ,@more)
+ (defvaralias ',secondary ',main ,docstring))))
+
+(eldoc--documentation-strategy-defcustom eldoc-documentation-strategy
+ eldoc-documentation-function
+ #'eldoc-documentation-default
+ "How to collect and organize results of `eldoc-documentation-functions'.
+
+This variable controls how `eldoc-documentation-functions', which
+specifies the sources of documentation, is queried and how its
+results are organized before being displayed to the user. The
+following values are allowed:
+
+- `eldoc-documentation-default': calls functions in the special
+ hook in order until one is found that produces a doc string
+ value. Display only that value;
+
+- `eldoc-documentation-compose': calls all functions in the
+ special hook and displays all of the resulting doc strings
+ together. Wait for all strings to be ready, and preserve their
+ relative as specified by the order of functions in the hook;
+
+- `eldoc-documentation-compose-eagerly': calls all functions in
+ the special hook and display as many of the resulting doc
+ strings as possible, as soon as possibl. Preserving the
+ relative order of doc strings;
+
+- `eldoc-documentation-enthusiast': calls all functions in the
+ special hook and displays only the most important resulting
+ docstring one at any given time. A function appearing first in
+ the special hook is considered more important.
+
+This variable can also be set to a function of no args that
+returns something other than a string or nil and allows for some
+or all of the special hook `eldoc-documentation-functions' to be
+run. In that case, the strategy function should follow that
+other variable's protocol closely and endeavor to display the
+resulting doc strings itself.
+
+For backward compatibility to the \"old\" protocol, this variable
+can also be set to a function that returns nil or a doc string,
+depending whether or not there is documentation to display at
+all."
:link '(info-link "(emacs) Lisp Doc")
:type '(radio (function-item eldoc-documentation-default)
(function-item eldoc-documentation-compose)
+ (function-item eldoc-documentation-compose-eagerly)
+ (function-item eldoc-documentation-enthusiast)
(function :tag "Other function"))
:version "28.1")
(defun eldoc--supported-p ()
"Non-nil if an ElDoc function is set for this buffer."
- (and (not (memq eldoc-documentation-function '(nil ignore)))
+ (and (not (memq eldoc-documentation-strategy '(nil ignore)))
(or eldoc-documentation-functions
;; The old API had major modes set `eldoc-documentation-function'
;; to provide eldoc support. It's impossible now to determine
- ;; reliably whether the `eldoc-documentation-function' provides
+ ;; reliably whether the `eldoc-documentation-strategy' provides
;; eldoc support (as in the old API) or whether it just provides
;; a way to combine the results of the
;; `eldoc-documentation-functions' (as in the new API).
;; But at least if it's set buffer-locally it's a good hint that
;; there's some eldoc support in the current buffer.
- (local-variable-p 'eldoc-documentation-function))))
-
-(defun eldoc-print-current-symbol-info ()
- "Print the text produced by `eldoc-documentation-function'."
- ;; This is run from post-command-hook or some idle timer thing,
- ;; so we need to be careful that errors aren't ignored.
- (with-demoted-errors "eldoc error: %s"
- (if (not (eldoc-display-message-p))
- ;; Erase the last message if we won't display a new one.
- (when eldoc-last-message
- (eldoc-message nil))
- (let ((non-essential t))
- ;; Only keep looking for the info as long as the user hasn't
- ;; requested our attention. This also locally disables inhibit-quit.
- (while-no-input
- (eldoc-message (funcall eldoc-documentation-function)))))))
-
-;; 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 (prefix doc &optional face)
- "Combine PREFIX and DOC, and shorten the result to fit in the echo area.
-
-When PREFIX is a symbol, propertize its symbol name with FACE
-before combining it with DOC. If FACE is not provided, just
-apply the nil face.
-
-See also: `eldoc-echo-area-use-multiline-p'."
- (when (symbolp prefix)
- (setq prefix (concat (propertize (symbol-name prefix) 'face face) ": ")))
- (let* ((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 prefix) (length doc)) ea-width)))
- (cond ((or (<= strip 0)
- (eq ea-multi t)
- (and ea-multi (> (length doc) ea-width)))
- (concat prefix doc))
- ((> (length doc) ea-width)
- (substring (format "%s" doc) 0 ea-width))
- ((>= strip (string-match-p ":? *\\'" prefix))
- 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.
- (concat (substring prefix strip) doc)))))
+ (local-variable-p 'eldoc-documentation-strategy))))
+
+(defvar eldoc--enthusiasm-curbing-timer nil
+ "Timer used by the `eldoc-documentation-enthusiast' strategy.
+When a doc string is encountered, it must endure a certain amount
+of time unchallenged until it is displayed to the user. This
+prevents blinking if a lower priority docstring comes in shortly
+before a higher priority one.")
+
+(defalias 'eldoc #'eldoc-print-current-symbol-info)
+
+;; This variable should be unbound, but that confuses
+;; `describe-symbol' for some reason.
+(defvar eldoc--make-callback nil "Helper for function `eldoc--make-callback'.")
+
+;; JT@2020-07-08: the below docstring for the internal function
+;; `eldoc--invoke-strategy' could be moved to
+;; `eldoc-documentation-strategy' or thereabouts if/when we decide to
+;; extend or publish the `make-callback' protocol.
+(defun eldoc--make-callback (method)
+ "Make callback suitable for `eldoc-documentation-functions'.
+The return value is a function FN whose lambda list is (STRING
+&rest PLIST) and can be called by those functions. Its
+responsibility is always to register the docstring STRING along
+with options specified in PLIST as the documentation to display
+for each particular situation.
+
+METHOD specifies how the callback behaves relative to other
+competing elements in `eldoc-documentation-functions'. It can
+have the following values:
+
+- `:enthusiast' says to display STRING as soon as possible if
+ there's no higher priority doc string;
+
+- `:patient' says to display STRING along with all other
+ competing strings but only when all of all
+ `eldoc-documentation-functions' have been collected;
+
+- `:eager' says to display STRING along with all other competing
+ strings so far, as soon as possible."
+ (funcall eldoc--make-callback method))
+
+(defun eldoc--invoke-strategy ()
+ "Invoke `eldoc-documentation-strategy' function.
+
+That function's job is to run the `eldoc-documentation-functions'
+special hook, using the `run-hook' family of functions. ElDoc's
+built-in strategy functions play along with the
+`eldoc--make-callback' protocol, using it to produce callback to
+feed to the functgions of `eldoc-documentation-functions'.
+
+Other third-party strategy functions do not use
+`eldoc--make-callback'. They must find some alternate way to
+produce callbacks to feed to `eldoc-documentation-function' and
+should endeavour to display the docstrings eventually produced."
+ (let* (;; How many callbacks have been created by the strategy
+ ;; fucntion and passed to elements of
+ ;; `eldoc-documentation-functions'.
+ (howmany 0)
+ ;; How many calls to callbacks we're still waiting on. Used
+ ;; by `:patient'.
+ (want 0)
+ ;; The doc strings and corresponding options registered so
+ ;; far.
+ (docs-registered '()))
+ (cl-labels
+ ((register-doc
+ (pos string plist)
+ (when (and string (> (length string) 0))
+ (push (cons pos (cons string plist)) docs-registered)))
+ (display-doc
+ ()
+ (eldoc--handle-docs
+ (mapcar #'cdr
+ (setq docs-registered
+ (sort docs-registered
+ (lambda (a b) (< (car a) (car b))))))))
+ (make-callback
+ (method)
+ (let ((pos (prog1 howmany (cl-incf howmany))))
+ (cl-ecase method
+ (:enthusiast
+ (lambda (string &rest plist)
+ (when (and string (cl-loop for (p) in docs-registered
+ never (< p pos)))
+ (setq docs-registered '())
+ (register-doc pos string plist)
+ (when (and (timerp eldoc--enthusiasm-curbing-timer)
+ (memq eldoc--enthusiasm-curbing-timer
+ timer-list))
+ (cancel-timer eldoc--enthusiasm-curbing-timer))
+ (setq eldoc--enthusiasm-curbing-timer
+ (run-at-time (unless (zerop pos) 0.3)
+ nil #'display-doc)))
+ t))
+ (:patient
+ (cl-incf want)
+ (lambda (string &rest plist)
+ (register-doc pos string plist)
+ (when (zerop (cl-decf want)) (display-doc))
+ t))
+ (:eager
+ (lambda (string &rest plist)
+ (register-doc pos string plist)
+ (display-doc)
+ t))))))
+ (let* ((eldoc--make-callback #'make-callback)
+ (res (funcall eldoc-documentation-strategy)))
+ ;; Observe the old and the new protocol:
+ (cond (;; Old protocol: got string, output immediately;
+ (stringp res) (register-doc 0 res nil) (display-doc))
+ (;; Old protocol: got nil, clear the echo area;
+ (null res) (eldoc--message nil))
+ (;; New protocol: trust callback will be called;
+ t))))))
+
+(defun eldoc-print-current-symbol-info (&optional interactive)
+ "Document thing at point."
+ (interactive '(t))
+ (cond (interactive
+ (eldoc--invoke-strategy))
+ (t
+ (if (not (eldoc-display-message-p))
+ ;; Erase the last message if we won't display a new one.
+ (when eldoc-last-message
+ (eldoc--message nil))
+ (let ((non-essential t))
+ ;; Only keep looking for the info as long as the user hasn't
+ ;; requested our attention. This also locally disables
+ ;; inhibit-quit.
+ (while-no-input
+ (eldoc--invoke-strategy)))))))
;; 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