Re: db._phrase

[Norman Walsh <ndw@nwalsh.com>]

Mike Maxwell <maxwell@umiacs.umd.edu> writes:
> From the on-line description of db._phrase
> (http://www.docbook.org/tdg5/en/html/_phrase.html):
>> This variant of phrase is used in places where
>> the content model is restricted to only the
>> “ubiquitous” inlines.
>
> Can someone explain to me what this means, and why it is necessary to
> have both db.phrase and db._phrase in DB5?  Unless I'm missing

The content model of db.phrase includes *all* the inlines. So if, for example,
db.phrase was allowed inside abbrev, then this would be legal:

  <abbrev><phrase><constant>PI</constant></phrase></abbrev>

even though this *is not* legal:

  <abbrev><constant>PI</constant></abbrev>

The db._phrase pattern defines <phrase> with a content model that's
limited to the ubiquitous elements. So putting db._phrase in abbrev
means you can use phrase but phrase can't contain constant in that
context.

Make sense?

> something, it was not necessary in earlier versions of DB (it doesn't
> appear in the "DocBook: The Definitive Guide" v1.0.3, although that is
> of course an older version).  (There is also a db._emphasis, in
> addition to the db.emphasis, although it's not clear that db._emphasis
> exists for the same reason as db._phrase--the '"ubiquitous" inlines
> isn't mentioned in the same way.)

It didn't occur before because it wasn't possible to do this sort of
thing with DTDs.
                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com>      | Convictions are more dangerous
http://www.oasis-open.org/docbook/ | enemies of truth than lies.--
Chair, DocBook Technical Committee | Nietzsche

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