Re: DOCBOOK: ELEMENT declaration in DTD

[Mike Sangrey <mike@sojurn.lns.pa.us>]

mike@sojurn.lns.pa.us said:
> Everywhere in the DocBook DTD files one sees lines like:
>    <!ELEMENT foobar - - ((some|stuff)*)> or
>    <!ELEMENT foobar - O ((some|stuff)*)>
> What are the '-' and 'O' doing in there?  A case of virtual beer if
> you  include an XML Spec. section citation.  :-) 

I've answered my own question.  The '- -' and '- O' indicate 
'Required'/'Optional' begin and end tags.  And (this is where my confusion 
lay), it is allowed in the more general SGML and _not_ in XML.

BTW, discovered this by looking at the source of a dtd2html PERL script.  I 
love Open Source. :-)

Thanks anyway.
-- 
Mike Sangrey
mike@sojurn.lns.pa.us
Landisburg, Pa.
       There is no 'do' in faith, everywhere present within it is 'done'.