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* History info in C-h f
@ 2018-09-28 19:11 Stefan Monnier
  2018-09-29  8:15 ` Michael Albinus
                   ` (2 more replies)
  0 siblings, 3 replies; 6+ messages in thread
From: Stefan Monnier @ 2018-09-28 19:11 UTC (permalink / raw)
  To: emacs-devel

Not sure if we should install this, especially since it's far from
reliable, but I've just whipped up the code below and figured some of
you might like it.

With this hack (which can go into your ~/.emacs), `C-h f defmacro`
dutifully informs you that `defmacro` was added to Emacs-1.2 (at least,
if you're on `master` and have upgraded very recently), whereas `C-h
f advice-add` informs you that it was only introduced in Emacs-24.4.


        Stefan


diff --git a/lisp/help-fns.el b/lisp/help-fns.el
index e15c96e6a3..a6c92103e6 100644
--- a/lisp/help-fns.el
+++ b/lisp/help-fns.el
@@ -574,6 +574,37 @@ help-fns--interactive-only
                          (t "."))
                    "\n")))))
 
+(add-hook 'help-fns-describe-function-functions #'help-fns--first-release)
+(defun help-fns--first-release (function)
+  "Try and find the first release that defined this function."
+  ;; Code below relies on the etc/NEWS* files.
+  ;; FIXME: Maybe we should also use the */ChangeLog* files when available.
+  ;; FIXME: Maybe we should also look for announcements of the addition
+  ;; of the *packages* in which the function is defined.
+  (when (symbolp function)
+    (let* ((name (symbol-name function))
+           (re (concat "\\_<" (regexp-quote name) "\\_>"))
+           (news (directory-files data-directory t "\\`NEWS.[1-9]"))
+           (first nil))
+      (with-temp-buffer
+        (dolist (f news)
+          (erase-buffer)
+          (insert-file-contents f)
+          (goto-char (point-min))
+          (search-forward "\n*")
+          (while (re-search-forward re nil t)
+            (save-excursion
+              (if (not (re-search-backward "^\\*.*in Emacs \\([0-9.]+\\)"
+                                           nil t))
+                  (error "Ref found in non-versioned section in %S"
+                         (file-name-nondirectory f))
+                (let ((version (match-string 1)))
+                  (when (or (null first) (version< version first))
+                    (setq first version))))))))
+      (when first
+        (insert (format "\nIntroduced at or before Emacs version %s.\n"
+                        first))))))
+
 (defun help-fns-short-filename (filename)
   (let* ((abbrev (abbreviate-file-name filename))
          (short abbrev))



^ permalink raw reply related	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2018-11-12  0:30 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2018-09-28 19:11 History info in C-h f Stefan Monnier
2018-09-29  8:15 ` Michael Albinus
2018-09-29 15:18 ` John Shahid
2018-09-29 15:30   ` Elias Mårtenson
2018-09-29 18:01   ` Stefan Monnier
2018-11-12  0:30 ` Drew Adams

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