Обсуждение: Why does SGML use zone=?

I see many places in the SGML docs that we do:

   <indexterm zone="functions-info">
    <primary>user</primary>
    <secondary>current</secondary>
   </indexterm>

In almost every case the "zone" tag has the same name as the section it
is in.  However, there are other cases that have no "zone" tag and they
default to the section they are in.  What I am wondering is why we
specify "zone" at all?  Why not just let it default to the section name?
Seems that would make writing and editing easier.

The SGML docs at:

    http://www.oasis-open.org/docbook/documentation/reference/html/indexterm.html

Say:

    Zone

        The use of Zone implies a spanning index entry. Zone holds the IDs
    of the elements to which it applies. The IndexTerm applies to the
    contents of the entire element(s) to which it points. If Zone is used,
    the phyiscal placement of the IndexTerm in the flow of the document is
    irrelavant.


It seems "zone" is for cases where you want to specify index terms
outside of the main document flow, but we don't do that.

--
  Bruce Momjian  <bruce@momjian.us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

Bruce Momjian wrote:
> What I am wondering is why we specify "zone" at all?

It means that the entire section is relevant to the index term.
Otherwise it would mean that only the narrow area around the index term
is relevant.  In printed renditions, that would be the difference
between saying

foo, 87

and

foo, 86-90

in the index.
--
Peter Eisentraut
http://developer.postgresql.org/~petere/

Peter Eisentraut wrote:
> Bruce Momjian wrote:
> > What I am wondering is why we specify "zone" at all?
>
> It means that the entire section is relevant to the index term.
> Otherwise it would mean that only the narrow area around the index term
> is relevant.  In printed renditions, that would be the difference
> between saying
>
> foo, 87
>
> and
>
> foo, 86-90
>
> in the index.

Ah, interesting.  Thanks.

--
  Bruce Momjian  <bruce@momjian.us>          http://momjian.us
  EnterpriseDB                               http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +