RE: DOCBOOK: ELEMENT declaration in DTD

["Mueller, Bob" <Bob.Mueller@compuware.com>]

> 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?  

----These are minimization tags. They are enabled in SGML by setting the
'OMITTAG' feature to 'YES'. (I'm not sure if this needs to be set in XML)
Basically, it specifies whether start and/or end tags are required for the
element (the first one represents the start tag, the other one, the end
tag). '-' means the tag is required, and (of course) 'O' means it does not
(we set everything to '-' to keep everything simple).

I do not know the XML Spec. section citation, but now that you know what it
is, you can probably find it. 

Bob Mueller
Compuware Corp.