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Re: Error Message Feedback: "valid 1.1"

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Fri, 27 May 2005 21:31:52 +0200
To: Chris Lilley <chris@w3.org>
Cc: www-validator@w3.org
Message-ID: <4299689c.5773359@smtp.bjoern.hoehrmann.de>

* Chris Lilley wrote:
>Okay. I suggest that it should use a lookup table of namespaces (to
>detect that its SVG) and then, having determined that it is SVG, it
>could usefully get more info from baseProfile (Tiny, Basic or Full) and
>version (1.0, 1.1, 1.2).

We currently dispatch based on the media type and user settings, trying
to sniff for content types is widely considered harmful and would not
work for e.g. application/xml with

  <svg version     = "1.1"
       baseProfile = "tiny"
       xmlns       = "http://www.w3.org/2000/svg"
       xsl:version = "1.0"
       xmlns:xsl   = "http://www.w3.org/1999/XSL/Transform" />

as that is a XSLT 1.0 document and should be processed per the XSLT 1.0
rules, not per SVG rules. So we would need to sniff and apply additional
heuristics to determine the type. And even if we do that, the SVG specs
contradict each other for the version attribute, in SVG Tiny 1.1 

  <svg baseProfile = "tiny"
       xmlns       = "http://www.w3.org/2000/svg" />

implementations must process the document as if it had version="1.1"
and in SVG Tiny 1.2 they apparently must process the document as if it
had version="1.2" (SVG Tiny 1.1 states that SVG 1.1 states it must be
set to 1.1 but that's just a SHOULD in SVG 1.1). Same for the base-
Profile attribute, it's optional and defaults to "none", so it's not
clear to me how to determine the exact conformance criteria that must
be checked for for any given image/svg+xml input either. And hence how
to make positive or negative statements about the document relative
to these criteria.

We could perhaps make up some 80/20 rules that generally work, but we
would likely have to make changes to that e.g. if SVG 1.3 comes out
which would mean the Validator gives different results over time which
is highly undesirable.
-- 
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
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Received on Friday, 27 May 2005 19:31:03 GMT

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