master 8420d7cce7 1/2: Add elisp-eldoc-var-docstring-with-value function

[Lars Ingebrigtsen]

branch: master
commit 8420d7cce72b7e6c69265e60c10a0ea4e420934c
Author: Štěpán Němec <stepnem@gmail.com>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Add elisp-eldoc-var-docstring-with-value function
    
    * lisp/progmodes/elisp-mode.el
    (elisp-eldoc-var-docstring-with-value): New function (bug#55096).
---
 etc/NEWS                     |  3 +++
 lisp/progmodes/elisp-mode.el | 29 ++++++++++++++++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/etc/NEWS b/etc/NEWS
index 9794807441..1fa2d086b9 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -1868,6 +1868,9 @@ functions.
 
 * Lisp Changes in Emacs 29.1
 
+---
+** New eldoc function: 'elisp-eldoc-var-docstring-with-value'.
+
 ** 'save-some-buffers' can now be extended to save other things.
 Traditionally, 'save-some-buffers' saved buffers, and also saved
 abbrevs.  This has been generalized via the
diff --git a/lisp/progmodes/elisp-mode.el b/lisp/progmodes/elisp-mode.el
index 70826b4c3a..84b7938bf0 100644
--- a/lisp/progmodes/elisp-mode.el
+++ b/lisp/progmodes/elisp-mode.el
@@ -1763,7 +1763,8 @@ Intended for `eldoc-documentation-functions' (which see)."
 
 (defun elisp-eldoc-var-docstring (callback &rest _ignored)
   "Document variable at point.
-Intended for `eldoc-documentation-functions' (which see)."
+Intended for `eldoc-documentation-functions' (which see).
+Also see `elisp-eldoc-var-docstring-with-value'."
   (let* ((sym (elisp--current-symbol))
          (docstring (and sym (elisp-get-var-docstring sym))))
     (when docstring
@@ -1771,6 +1772,32 @@ Intended for `eldoc-documentation-functions' (which 
see)."
                :thing sym
                :face 'font-lock-variable-name-face))))
 
+(defun elisp-eldoc-var-docstring-with-value (callback &rest _)
+  "Document variable at point.
+Intended for `eldoc-documentation-functions' (which see).
+Also see `elisp-eldoc-var-docstring-with-value'."
+  (when-let ((cs (elisp--current-symbol)))
+    (when (and (boundp cs)
+              ;; nil and t are boundp!
+              (not (null cs))
+              (not (eq cs t)))
+      (funcall callback
+              (format "%.100S %s"
+                      (symbol-value cs)
+                      (let* ((doc (documentation-property
+                                    cs 'variable-documentation t))
+                             (more (- (length doc) 1000)))
+                        (concat (propertize
+                                 (string-limit (if (string= doc "nil")
+                                                   "Undocumented."
+                                                 doc)
+                                               1000)
+                                 'face 'font-lock-doc-face)
+                                (when (> more 0)
+                                  (format "[%sc more]" more)))))
+              :thing cs
+              :face 'font-lock-variable-name-face))))
+
 (defun elisp-get-fnsym-args-string (sym &optional index)
   "Return a string containing the parameter list of the function SYM.
 If SYM is a subr and no arglist is obtainable from the docstring