Re: Suggestion: Let the help command load autoloaded functions etc

[Lennart Borgman (gmail)]

David Kastrup wrote:
> "Stephen J. Turnbull" <address@hidden> writes:
>
> > Lennart Borgman writes:
> >
> >  > > > I think that will be too long. How about this:
> >  > > >
> >  > > >   [To see Arg list, _click for loading library above_]
> >  > >
> >  > I think "_click for loading library_" is my favorite.
> >
> > The file name probably has the full path, which is indeed too long.
>
> I don't see why it should have the full path.  The autoload cookies
> don't usually have this info in them, so there is no point in deriving
> and displaying it before the time of the load.
>
> > I don't volunteer to do the work, but how about
> >
> >     [To see Arg list, _click for loading LIBNAME_]
> >
> > where LIBNAME is the library name (ie, basename without .el), and add
> > a tooltip with the full file name.
> >
> > By the way, the English usage can be improved.  Here are some
> > variations:
> >
> > _Show Arg list_ (loads LIBNAME).
>
> I think in the context of the arg list, I find this text the most
> straightforward suggestion yet.  It has a link for the point of interest
> and mentions the side effect as a side effect.
>
> > To show Arg list, _click to load LIBNAME_.
>
> Clearly inferior.  The other proposal is much more of an improvement
> over my suggestion.

Thanks David and Stephen. I have attached a patch similar to Stephen's 
suggestion, but a little bit more verbose.

If this looks good then please install it.

Index: help-fns.el
===================================================================
RCS file: /sources/emacs/emacs/lisp/help-fns.el,v
retrieving revision 1.122
diff -u -r1.122 help-fns.el
--- help-fns.el 6 Jun 2008 20:02:42 -0000       1.122
+++ help-fns.el 16 Jul 2008 21:07:29 -0000
@@ -104,7 +104,7 @@
    ((byte-code-function-p def) (aref def 0))
    ((eq (car-safe def) 'lambda) (nth 1 def))
    ((and (eq (car-safe def) 'autoload) (not (eq (nth 4 def) 'keymap)))
-    "[Arg list not available until function definition is loaded.]")
+    "[Show arg list and full help (loads library LIBNAME).]")
    (t t)))
 
 (defun help-make-usage (function arglist)
@@ -417,7 +417,25 @@
                  (high (help-highlight-arguments use doc)))
             (let ((fill-begin (point)))
              (insert (car high) "\n")
-             (fill-region fill-begin (point)))
+             (fill-region fill-begin (point))
+              ;; Add load link for autoloaded functions.
+              (let ((here (point-marker))
+                    (load-marker
+                     (concat "\\(Show arg list and full help\\) "
+                             "(loads library \\(LIBNAME\\))\.")))
+                (goto-char fill-begin)
+                (save-match-data
+                  (when (re-search-forward load-marker here t)
+                    (make-text-button (match-beginning 1)
+                                      (match-end 1)
+                                      'action `(lambda (btn) (interactive)
+                                                 (load-library ,file-name)
+                                                 (describe-function 
',function)))
+                    (replace-match
+                     (file-name-sans-extension
+                      (file-name-nondirectory file-name))
+                     t t nil 2)))
+                (goto-char here)))
             (setq doc (cdr high))))
         (let* ((obsolete (and
                          ;; function might be a lambda construct.