Re: DTD extensions

Terry Allen <>
Message-id: <>
From: Terry Allen <>
Date: Mon, 16 Aug 1993 08:15:50 PDT
X-Mailer: Mail User's Shell (7.2.0 10/31/90)
Subject: Re: DTD extensions
Status: RO
 > From: Lou Burnard <>
 > Subject: DTD extensions and modifications
 > Should there be one DTD only for HTML? 

There CAN be only one DTD for HTML+ (forget about HTML, that's frozen)

 > What if my browser wants/knows
 > about/must have some elements that yours doesn't? 

Write an extension to the DTD.

 > What if I want to tag
 > my documents in some language other than English?  

Why?  tags are markup, not content.  
[TEI stuff, all appropriate for TEI but not really needed here:] 
 > All elements in the TEI dtd are declared indirectly. 
This is only indirection, with provision for extension.  It 
doesn't mean having multiple DTDs.

 > All(most) elements in the TEI dtd are assigned to a class, ...

This is about restricting contents to particular contexts, coming
in HTML+.
 > Every element declaration in the TEI dtd is bracketed by a marked
 > section named for the element itself, the value of which is by default
 > 'include' but which can be changed to 'ignore' in the DTD subset. So, to
 > remove the current definition for 'blort' (either because you don't want
 > to allow blorts or because you want to substitute your own definition
 > for them -- not a good idea, but it happens --)  you just bung a 
 > <!ENTITY blort 'IGNORE'> into your dtd subset and kiss those blorts
 > goodbye (sorry Sebastian)
Sure, you can cut down your HTML+ DTD; that won't hurt anything.  You
don't need the TEI method to accomplish that.

 > Every elements in the TEI dtd is defined in one  'tagset' or dtd
 > fragment. 

A way to encourage modifications; why do we need this for HTML+?

Terry Allen  (
Editor, Digital Media Group
O'Reilly & Associates, Inc.
Sebastopol, Calif., 95472