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Re: ISSUE-54: doctype-legacy-compat

From: Philip TAYLOR (Ret'd) <P.Taylor@Rhul.Ac.Uk>
Date: Tue, 20 Jan 2009 14:45:39 +0000
Message-ID: <4975E393.60502@Rhul.Ac.Uk>
To: Jirka Kosek <jirka@kosek.cz>
CC: HTML WG <public-html@w3.org>



Jirka Kosek wrote:

> Giving completely aside question whether version information should or
> shouldn't be included it is very bad idea to include it in DOCTYPE. The
> version number should be encoded in both XML and HTML serializations in
> the same way. But information from DOCTYPE is not a part of many XML
> data models and XML APIs and is thus not easily accessible without
> resorting to custom parsers.

Well, I am no expert on XML, but reading the W3C specification
for XHTML 1.1 [1] I see the following (under 2.1.1, Strictly Conforming
Documents)

> There MUST be a DOCTYPE declaration in the document prior to the root element.
> If present, the public identifier included in the DOCTYPE declaration MUST 
> reference the DTD found in Appendix C using its public identifier. The system 
> identifier MAY be modified appropriately.

> <!DOCTYPE
>  html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
>  "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

For XHTML 2.0 [2] I find

> There should be a DOCTYPE declaration in the document prior to the root element. If present, the public identifier included in the DOCTYPE declaration must reference the DTD found in Appendix F using its Public Identifier. The system identifier may be modified appropriately.
> 
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 2.0//EN"
>     "http://www.w3.org/MarkUp/DTD/xhtml2.dtd">

but I note that the MUST of XHTML 1.1 has been watered down
to a SHOULD for XHTML 2.0.

The 2.0 "Strictly conforming" example then goes on to include :

> <html xmlns="http://www.w3.org/2002/06/xhtml2/" xml:lang="en"
>       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
>       xsi:schemaLocation="http://www.w3.org/2002/06/xhtml2/
>                           http://www.w3.org/MarkUp/SCHEMA/xhtml2.xsd"
>

so would I be safe in assuming that when you write

> So, if there should be version specified, then it should definitively
> live in attribute or element value, probably version attribute would be
> the best choice then.

you are advocating something along the lines of the <html> element
+ attributes cited immediately above ?  If so, I agree that this
would allow an HTML document to unequivocally define to which
version of the specification it is claiming adherence, in which
case I would also agree that duplicating this information in
the DOCTYPE is not essential and may well be contra-indicated.

I would also be interested to know (are there any XHTML 2.0 WG
members here ?) what benefit(s) the XHTML WG perceive in this
duplication.

Philip TAYLOR
--------
[1] http://www.w3.org/TR/xhtml11/conformance.html#strict
[2] http://www.w3.org/TR/xhtml2/conformance.html#s_conform
Received on Tuesday, 20 January 2009 14:46:22 GMT

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