Re: [ELPA] New package: marginalia

[Juri Linkov]

>>> BTW, I hope we can merge some of that code directly into Emacs itself.
>> 
>> For example, marginalia--symbol-class adds new symbol characters to
>> the replacement of `help--symbol-completion-table-affixation',
>> but it would be better to add new characters directly to
>> `help--symbol-completion-table-affixation'...
>
> Yes, I would be glad if you merge back the `marginalia--symbol-class` to
> the Emacs help system! The `marginalia--symbol-class` has been inspired
> by your `help--symbol-completion-table-affixation`, but I wanted to go a
> little step further in Marginalia. Maybe it makes sense to add
> `help--symbol-class` such that the function can be reused potentially at
> other places?

Maybe something like

diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index 5a805a2302..133763add1 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -126,29 +126,35 @@ help-enable-completion-autoload
   :group 'help
   :version "26.3")
 
+(defun help--symbol-class (s)
+  "Return symbol class characters for symbol S."
+  (when (stringp s)
+    (setq s (intern-soft s)))
+  (cond ((commandp s)
+         "c")                           ; command
+        ((eq (car-safe (symbol-function s)) 'macro)
+         "m")                           ; macro
+        ((fboundp s)
+         "f")                           ; function
+        ((custom-variable-p s)
+         "u")                           ; user option
+        ((boundp s)
+         "v")                           ; variable
+        ((facep s)
+         "a")                           ; fAce
+        ((and (fboundp 'cl-find-class)
+              (cl-find-class s))
+         "t")                           ; CL type
+        (" ")                           ; something else
+        ))
+
 (defun help--symbol-completion-table-affixation (completions)
   (mapcar (lambda (c)
             (let* ((s (intern c))
                    (doc (condition-case nil (documentation s) (error nil)))
                    (doc (and doc (substring doc 0 (string-match "\n" doc)))))
               (list c (propertize
-                       (concat (cond ((commandp s)
-                                      "c") ; command
-                                     ((eq (car-safe (symbol-function s)) 
'macro)
-                                      "m") ; macro
-                                     ((fboundp s)
-                                      "f") ; function
-                                     ((custom-variable-p s)
-                                      "u") ; user option
-                                     ((boundp s)
-                                      "v") ; variable
-                                     ((facep s)
-                                      "a") ; fAce
-                                     ((and (fboundp 'cl-find-class)
-                                           (cl-find-class s))
-                                      "t")  ; CL type
-                                     (" ")) ; something else
-                               " ")         ; prefix separator
+                       (concat (help--symbol-class s) " ") ; prefix separator
                        'face 'completions-annotations)
                     (if doc (propertize (format " -- %s" doc)
                                         'face 'completions-annotations)

Then you could use it, and prepend/append more characters
such as: o for obsolete, ! for advised, * for modified.