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Re: The argument for |bugmode|

From: Terje Bless <link@pobox.com>
Date: Fri, 20 Apr 2007 10:03:56 +0200
To: W3C HTML WG <public-html@w3.org>
Message-ID: <r02020000-207-1049-ppc-2E6D2B2648364FED97601BEFFA31D7CB@pounder.local>

mjs@apple.com (Maciej Stachowiak) wrote:

>If the comment was a syntactically valid comment then I believe it would
>affect conformance status. And this should be so; otherwise, an
>implementation that has any arbitrary behavior in the presence of at least
>one comment would remain conformant.

If the standard leaves undefined how to detect that the document 
instance is “HTML 5” — as opposed to “HTML 4.01” or 
“HTML 6” — then an implementation using syntactically 
valid, but undefined, mechanisms to determine this can be argued 
to be conforming.

In either case, if an UA implementation has multiple processors 
for “HTML 5” — assume for the sake of argument that they 
are all conforming — then the mechanism used to determine 
which specific processor to employ — be it by local 
application setting, interactive user choice, or a “magic 
comment” (aka. a Processing Instruction) — does not in 
itself affect the implementation's conformance status.

Given the goals given for WHATWG HTML5, it's even arguable — 
not that I would — whether treating a conforming HTML5 
document instance as tagsoup would render the implementation 
non-conforming as such.


Particularly, IIRC, when faced with the text/html MIME type 
there is only one specified default DTD — HTML 2.0 — 
associated with the “html” document type name. In the 
absence of a specific FPI or SI (or Internal Subset, but I 
digress), this would historically have been the only available option.

Thus an UA attempting to conform with the wide variety of 
documents served as “text/html”, when presented with only 
the document type name “html” and no other versioning 
information, would need some such mechanism in order to be 
compliant with all the relevant standards.

If the higher level language is SGML or XML, then a “magic 
comment” in the form of a Processing Instruction would be an 
entirely appropriate way to achieve this.


In considering the question of versioning, it would be a good 
idea to consider previous relevant standards, and not just the 
proposed “HTML5” in isolation.


>However, embedding a comment that some UAs treat specially would not affect
>conformance status of the document.

I believe this was Chris' salient point.


-- 
>For all I know they probably have a standard for
>which direction to put the thread on a bolt.

That would be ISO 261:1973.         -- John Cowan
Received on Friday, 20 April 2007 08:04:08 GMT

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