[osis-core] Index

[Harry Plantinga]

> It seems that giving index a FIXED number of levels is a short sighted
> solution.
>
> I would rather see a solution where the index is expressed in a single
> attribute, with its level oriented components delimited by some character.
> It is possible to have a numeric level attibute to indicate the level of
the
> index.  Further, the "see" attribute would have the same form as the index
> itself (all one string).   This would give us a much more flexable
solution
> without giving up anything.

Most indexes in books I've seen have only two levels, though I've seen a
handful with three. I don't recall ever having seen one with four levels.
In practice, it's very hard to construct and use a deep hierarchy (three or
more levels) consistently without having a pre-defined standard set of
topic names.

Encoding the subject levels into a single attribute makes the index harder
to build -- parsing out pieces of an attribute is quite hard in XSLT
(though it would be easy to do in perl). So one advantage of using separate
attributes is the ability to sort and generate the index in XSLT.

-Harry