bug#46627: [PATCH] Add new help command 'describe-command'

[Stefan Kangas]

Eli Zaretskii <eliz@gnu.org> writes:

>> I can't claim that it is the most effective technique in general.
>> I would use it when I am certain that I almost know the name of a
>> command -- I would know it if I see it.  In such situations, firing up
>> apropos is an extra step and not what I want.
>
> Can you explain how apropos is an extra step, compared to TAB
> completion followed by browsing through the candidates?  I see no
> extra step here.

So I type `C-h a foobar RET'.

Now I realize I want to look for "foobaz", so `C-h a foobaz RET'.

Now I realize that oops, I meant "barsnaz", etc.

Typing this at a prompt is often faster for me.  In particular, I don't
need to rewrite everything for minor changes.

Yes, I can be smarter and say `C-h a M-p DEL z RET', but I think we can
agree that `DEL z TAB' is less typing.  (BTW, with many completion
frameworks you don't even need the TAB.)

Plus I often look only for names, and don't need to waste screen real
estate on documentation (which I would using apropos).

> "C-h a" accomplishes that.  It is no accident that it's the very first
> Help command mentioned in the user manual.  In addition, "C-h a" is
> more powerful, as it accepts regular expressions and lists of
> keywords, whereas completion has only crude and less powerful
> approximations of those.

Many popular completion frameworks have regexps, lists, fuzzy search,
etc.  But yes, our default one does not.

>> (BTW, in the completion framework I often use, `ivy', there is a command
>> to run the action associated with the minibuffer without leaving the
>> minibuffer.  That is, I run `C-h f', type in some text to complete on,
>> and then hit `C-M-n' to repeatedly see the full documentation for a
>> number of commands.
>
> You can likewise type "C-h a", then, with point on the command you
> were after, type "M-x <DOWN> RET" or "M-x M-n RET" to invoke that
> command.  So the task of finding a command and then quickly invoking
> it already has a well-developed solution in Emacs, one that is more
> powerful than completion.

Sure, you can do that.  It is in my view often slower (and more typing)
than the workflow I described, but of course that also depends on the
circumstances.

I don't see that we need to agree about the relative efficiency of these
workflows.  We can and do support both workflows well.