bug#68236: [PATCH] help.el: allow help-quick to use local commands/quick-sections

[Eli Zaretskii <eliz@gnu.org>]

> From: JD Smith <jdtsmith@gmail.com>
> Date: Thu, 4 Jan 2024 20:28:27 -0500
> Cc: 68236@debbugs.gnu.org
> 
> > On Jan 4, 2024, at 8:57 AM, Eli Zaretskii <eliz@gnu.org> wrote:
> > 
> > If we are going to expose help-quick-sections as a defcustom, then I
> > don't understand why we need to change the code at all.  Is the idea
> > that sections will depend on the current buffer?  If so, then we just
> > need to add an element to the list members which will store the
> > major-mode for which the member is relevant.
> > 
> > Or what am I missing?
> 
> Right now the code does
> 
>   (with-current-buffer (get-buffer-create "*Quick Help*")
> 
> right away, then checks `where-is-internal' for each listed command in `help-quick-sections'.  So only global bindings (and bindings available in help-mode) are accessible for display.  My patch simply delays switching to *Quick Help* buffer, so that binding information can be gathered from the local buffer from which quick help was summoned.  Note that help-quick omits any bindings that are nil, as well as any empty sections.  So adding sections to the defcustom that do not apply (=have no bindings) in some buffer is not a problem.  

Your proposal has the disadvantage that the user must switch to a
buffer under some major mode to see the entries for that mode in the
quick-help window.  It could be an annoyance; e.g., consider a user
who wants to see this while in a *Help* buffer.  And I don't think
being in the buffer under the major mode is the only way of getting
mode-specific bindings; for example, where-is-internal can accept a
KEYMAP argument, which will be used to find key bindings.

Or maybe we should have a separate command for cheat sheets specific
to a major mode.  The window we pop up cannot be too large, so if the
user only wants a quick help for the current mode, she might consider
global bindings an annoying waste of screen estate.  Moreover, the
current quick help shows "popular commands", which are likely to be
already known to some users, whereas when the user works in a major
mode that is new to the user, one is likely to be in the need of the
cheat sheet for that one mode.  (Yes, we do already have "C-h b", but
the output of that could be overwhelming: for example in an Org buffer
I get almost 1400 lines in the *Help* buffer showing the Org-specific
bindings.)

IOW, if we want to consider mode-specific quick help, we should
perhaps discuss more about the goals before we consider code tricks to
implement it.

Stefan, WDYT?