Re: progress on HTML 2.0 reconstruction

Christophe ESPERT (
Wed, 29 Mar 95 07:09:57 EST

In message <> 29 Mar 95 04:37:37, wrote:

> Example: the following document should get type "text/sgml", despite
> the public identifier:
> -----------------------------------------------
> <!doctype html public "-//IETF//DTD HTML//EN" [
> <!element html o o (head, body) +(blue)>
> <!element blue - - any>
> ]>
> ...
> <blue>
> <p>blue, blue, blue,...
> </blue>
> ...
> -----------------------------------------------

Unfortunately this won't work because you are not allowed to define an element
twice in the DTD. Let's recall that the DTD is made of the markup
declarations coming from the declaration subset and from the entity pointed
to by the external identifier PUBLIC "-//IETF//DTD HTML//EN" which is
concatenated right after the subset. So here the first HTML element declaration
would be the one you define in the subset and would be conflicting with the
one in the external entity.
The only thing you may declare twice are entities. In the case where an entity
is declared twice the first definition in the order of recognition counts.

Otherwise I totally support Bert's and Joe's opinions. If one can give
advice regarding implementation perspectives, I'd say that the browser
should send a message to the user to tell him/her about unrecognized
markup in the document.


Christophe Espert - E-mail:
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ISO 8879:1986 - SGML | ISO/IEC 10744:1992 - HyTime | ISO/DIS 10179 DSSSL