For anyone interested in producing classical indices locorum, I have
devised a way that seems to work, although it is not that elegant.

The first step is to modify the sort keys by counting the number of digits
in the page number:
thus,
[AuthorText01] for pages 1–9,
[AuthorText02] for pages 10–99, and so on

The next is to insert the command “ \ab” (note the space) when the line
number is a single digit:
thus
391. \ab{}2 but 391.12 in the entry specification {Author+Text+page.line}

For \ab, I have:

\newdimen\digitwidth
\setbox0=\hbox{\tfx\char32}
\digitwidth=\wd0

\def\ab{\tfx\kern-\digitwidth}

The hitch here is that the font size is not context dependent.

Alan

On Tue, May 22, 2012 at 6:39 PM, Alan Bowen <bowenalan03@gmail.com> wrote:

> I have been trying to index the passages cited in a book and would be
> grateful for some tactical advice.
>
> There are several works by a single author, and it is customary to cite
> each text by page and line number, as in 1253.12 (page 1253, line12), for
> example.
>
> I have a sort key for each work. But now I need a way to get the entry
>
> 1253.7 (page 1253, line 7) before the entry
> 1253.12 (page 1253, line 12).
>
> \[Passage[AuthorText]{Author+Text+1253.07}1253.7 or
> \[Passage[AuthorText]{Author+Text+1253.07}1253. 7
> would work, but it is really better to have the index entry as “1253.7”
> rather than as “1253.07” or “1253. 7”
>
> I have experimented with different sort keys—e.g., AuthorText125307—and
> can generate an index with the 1235.7 and so on in the proper place and
> form, say, before 1253.12.
>
> But then the problem is that I also get entire sequences of entries out of
> order (485.19, 485.21 before 477.31, and so on). Very puzzling. (Restoring
> the sort key AuthorText removes the latter problems but then leaves 1253.7
> in the wrong place.)
>
> If anyone has experience with this or just some ideas for a solution,
> their suggestions will be most welcome.
>
> I am using the MKII in the latest ConTeXt standalone.
>
> Alan
>
>
>
>