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Re: Inclusion in XML versus SGML

• To: Benoit.Sevigny@m...
• Subject: Re: Inclusion in XML versus SGML
• From: "Eve L. Maler" <eve.maler@s...>
• Date: Wed, 20 Feb 2002 13:20:43 -0500
• Cc: xml-dev@l...
• In-reply-to: <E16da8t-00009i-00@m...>
• References: <D98A27074EF37B408E838BCF7F41AC70080A35@s...>

The effect of <!ELEMENT book (chapter,section) +(para)> probably isn't 
what's wanted anyway.  This would also allow paragraphs before chapters, 
between chapters and sections, and after sections.  And in addition, I 
suspect that chapters would want to contain sections, not sit next to them, 
so the example is a little artificial.

Inclusion has often been used in SGML when regular content models (usually 
repeatable-OR groups) would have been a better choice.  If the document 
type really is for books, there are plenty of examples of how to do this 
using good practices -- DocBook, for example.

Once upon a time I wrote a white paper about migrating SGML DTDs with 
exceptions (inclusions and exclusions) into XML.  Looks like it's still up; 
it hasn't aged too terribly badly, assuming that the migration is into XML 
DTDs and not more modern schemas:

   http://www.arbortext.com/html/exceptions_wp.html

         Eve

At 12:02 PM 2/20/02 -0500, John Cowan wrote:
>Sevigny Benoît scripsit:
>
> >       In SGML, you can do like thing in your DTD declaration :
> >
> >               <!ELEMENT book (chapter,section) +(para) >
> >
> >       This mean that that book contain a chapter and a section. The
> > chapter and section is composed by para.
> >
> >       Now what I want to know, is how in XML I can declare such thing
> > (a repeating inclusion).
>
>XML DTDs don't have inclusions, period.
>
>You can either carefully define all your content models to allow
><para> elements at every point (which often isn't that hard), or
>you can move to a different schema language.

--
Eve Maler                                    +1 781 442 3190
Sun Microsystems XML Technology Center   eve.maler @ sun.com

• References:
  • Inclusion in XML versus SGML
    • From: Sevigny Benoît <Benoit.Sevigny@m...>
  • Re: Inclusion in XML versus SGML
    • From: John Cowan <cowan@m...>

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