Re: Do not merge index entries with equal sort keys?

On Mon, Apr 27, 2026 at 02:48:23PM +0300, Eli Zaretskii wrote:
> > From: Gavin Smith <[email protected]>
> > Date: Sun, 26 Apr 2026 22:01:37 +0100
> > Cc: [email protected]
> > 
> > I remember that the convention of merging index entries with the
> > same sort key was very old (from when I looked at this before, several
> > years ago), but I thought we could reconsider this, as I do not actually
> > see any advantage of merging the entries.
> > 
> > Does anyone have an opinion on this?
> 
> Isn't this what causes the Index to have stuff like
> 
>   Foo bar.......................................42, 142, 442
> 
> rather than
> 
>   Foo bar.......................................42
>   Foo bar.......................................142
>   Foo bar.......................................442
> 
> That is, if the same subject is mentioned in several places, have on
> cumulative entry for it in the index with all the pages?  If so, I
> see a clear advantage to merging the entries, at least for
> non-punctuation characters.

I propose that they only be merged if the index entry text is identical.

Thus, the following two index entries should be merged:

@cindex Foo bar
@cindex Foo bar

However, the following index entries should be distinct:

@cindex Foo bar
@cindex Foo @code{bar}
@cindex Foo @command{bar}
@cindex Föö bar

I notice in the NEWS file for Texinfo, in the section for 6.0, there
is:

* texindex:
  . completely new implementation as a literate program using Texinfo
    and (portable) awk (called TexiWeb Jr.), thanks to Arnold Robbins.
    (Requires gawk 4.0+ if .twjr source is modified.)
  . the -o (--output) is not supported, unless we hear of someone using it.
  . duplicated sort keys with different display texts result in one
    merged index entry, using the first display text.
  . better sorting and parsing in unusual cases; most notably, { and }
    characters can appear as initials.

Bullet point 3 is what I am talking about here.