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Re: ISSUE-92 (xml:base): xml:base not included [DFXP 1.0]

From: Glenn A. Adams <gadams@xfsi.com>
Date: Wed, 06 May 2009 07:06:29 +0800
To: Sean Hayes <Sean.Hayes@microsoft.com>, Public TTWG List <public-tt@w3.org>
Message-ID: <C626E775.A760%gadams@xfsi.com>

The schemas are normative in the sense that we define them as "normative".
They are not normative in the sense of defining validiy of a DFXP document
instance. The text in 4.1 says "validate a SUBSET...". See also the note at
end of 4.1. [If the note is wrong about false negatives, then we need to
tune the schemas to not complain about foreign namespace elements and

Also see Appendix C which says:

"In any case where a schema specified by this appendix differs from the
normative definitions of document type, element type, or attribute type as
defined by the body of this specification, then the body of this
specification takes precedence."

So, in effect, the schemas we publish are not definitive w.r.t. DFXP
validity, which is a decision we made some time ago.


On 5/6/09 7:00 AM, "Sean Hayes" <Sean.Hayes@microsoft.com> wrote:

> 4.1 seems to contradict that:
> "This specification defines two types of normative schemas that may be used to
> validate a subset of conformant DFXP document instances:"
> If we are going to make abstract document validity the normative one, then the
> schemas should become informative.
> Sean Hayes
> Media Accessibility Strategist
> Accessibility Business Unit
> Microsoft
> Office:  +44 118 909 5867,
> Mobile: +44 7875 091385
> -----Original Message-----
> From: public-tt-request@w3.org [mailto:public-tt-request@w3.org] On Behalf Of
> Glenn A. Adams
> Sent: 05 May 2009 11:51 PM
> To: Public TTWG List
> Subject: Re: ISSUE-92 (xml:base): xml:base not included [DFXP 1.0]
> this is already permitted by means of section 4 item 3; so you may close
> this issue;
> On 5/6/09 3:20 AM, "Timed Text Working Group Issue Tracker"
> <sysbot+tracker@w3.org> wrote:
>> ISSUE-92 (xml:base): xml:base not included [DFXP 1.0]
>> http://www.w3.org/AudioVideo/TT/tracker/issues/92
>> Raised by: Sean Hayes
>> On product: DFXP 1.0
>> We did not include xml:base in the timed text specification, because as timed
>> text makes no external references it was deemed unnecessary. However this may
>> cause an unfortunate side effect making it unable to interoperate with
>> XInclude.
>> The XInclude spec says:
>> "Each element information item in the top-level included items which has a
>> different base URI than its include parent has an attribute information item
>> added to its attributes property. This attribute has the following
>> properties:
>> .... [describes xml;base attribute]"
>> Since timed text has no external references, it has no base URI, so itıs not
>> 100% clear whether the xml:base should be added as a result of this clause
>> (and it may be suppressed by user option), however if it is (which it seems
>> to
>> be in practice); this would prevent the resulting dfxp document from
>> validating against the schema.
>> proposal: allow xml:base on elements in the schema, but indicating that its
>> value is ignored in the prose.
Received on Tuesday, 5 May 2009 23:07:20 UTC

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