bug#3692: 23.0.95; `i' in Info, when in multiple indexes but same target

bug#3692: 23.0.95; `i' in Info, when in multiple indexes but same target

[Drew Adams]

emacs -Q
C-h r
i truncate-lines
,
,
 
When a matching entry is found in more than one index (or more than
once in the same index), you get a message such as the following:
 
Found `truncate-lines' in Variable Index.  (2 total; use `,' for next)
 
When all of the targets are identical, or even when they are in the
same node, this message is not too helpful. Repeated use of `,' stays
in the same node.
 
On the other hand, it can be helpful to know that the same term is an
entry in both the Command index and the Variable index (for example).
 
It would be good if this behavior could be improved a bit, so that
equivalent targets are filtered in some way, and that you are told
when they are entered in different indexes. I don't have a great idea
about the best way to do that. I just notice that the help that is
given is not as helpful as it might be. So I guess this is a feature
request.

In GNU Emacs 23.0.95.1 (i386-mingw-nt5.1.2600) of 2009-06-19 on
 SOFT-MJASON Windowing system distributor `Microsoft Corp.', version
 5.1.2600 configured using `configure --with-gcc (3.4)'
 

bug#3692: 23.0.95; `i' in Info, when in multiple indexes but same target

[Lars Ingebrigtsen]

"Drew Adams" <drew.adams@oracle.com> writes:

> When a matching entry is found in more than one index (or more than
> once in the same index), you get a message such as the following:
>
> Found `truncate-lines' in Variable Index.  (2 total; use `,' for next)

I've now changed this to remove the duplicates in Emacs 28.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#3692: 23.0.95; `i' in Info, when in multiple indexes but same target

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Thu, 03 Jun 2021 11:56:15 +0200
> Cc: 3692@debbugs.gnu.org
> 
> "Drew Adams" <drew.adams@oracle.com> writes:
> 
> > When a matching entry is found in more than one index (or more than
> > once in the same index), you get a message such as the following:
> >
> > Found `truncate-lines' in Variable Index.  (2 total; use `,' for next)
> 
> I've now changed this to remove the duplicates in Emacs 28.

I think this change is incorrect, and should be reverted.  An Info
manual cannot possibly have duplicate index entries; if the Texinfo
source does have such duplicate entries, 'makeinfo' will rename them
by appending a numeric "<n>" tail.

The code which was modified tries to look for partial matches to what
the user typed at the 'i's prompt, and that _can_ indeed include
duplicates where what the user typed matches a substring of some index
entry.  But those duplicates cannot be removed, because then Info will
not show all the matches.  For example, in this case the 2 matches are
"truncate-lines" and "toggle-truncate-lines"; with the change just
installed, Emacs shows only one of them, and typing ',' doesn't help
to show the other one.

Going back to the original report:

> When all of the targets are identical, or even when they are in the
> same node, this message is not too helpful. Repeated use of `,' stays
> in the same node.

If this happens, it's a bug in the indexing, not in the Info reader:
similar, let alone identical, index entry in the same node, especially
when they are close to each other, should be avoided.

> On the other hand, it can be helpful to know that the same term is an
> entry in both the Command index and the Variable index (for example).

The response to multiple matches says how many matches it found and
shows the first of them with its node.  Other nodes will be shown when
you type ','.  there isn't enough screen estate in the echo area to
show each match with its node (and I personally think the node in
which you find a match is not very important for the purpose that the
index-search serves).

So I think there's nothing we should do about this bug report, except
being vigilant to patches that introduce similar index entries close
to one another.

bug#3692: 23.0.95; `i' in Info, when in multiple indexes but same target

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> But those duplicates cannot be removed, because then Info will
> not show all the matches.  For example, in this case the 2 matches are
> "truncate-lines" and "toggle-truncate-lines"; with the change just
> installed, Emacs shows only one of them, and typing ',' doesn't help
> to show the other one.

Ah; I didn't notice that the `i' command was finding two different
things on the same line.

I've reverted the patch now.

> So I think there's nothing we should do about this bug report, except
> being vigilant to patches that introduce similar index entries close
> to one another.

Yup; closing.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no