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Re: Notes on validome test suite / validators comparison

From: olivier Thereaux <ot@w3.org>
Date: Wed, 24 Oct 2007 13:28:25 +0900
Message-Id: <D5BD5A9A-47B3-4668-8816-4B47AAC18E30@w3.org>
Cc: <www-validator@w3.org>
To: Validome-Staff <staff@validome.org>

Hi Alex,

Thanks a lot for going through the list, and giving more references.  
This is very useful.

On Oct 20, 2007, at 00:05 , Validome-Staff wrote:
> Here Validome advices the user to use our XML-Validator, as a HTML- 
> Validator is not the appropriated tool to check XML...;-)

Understood, but as I wrote, I think it's not very good usability to  
call this a fatal error, when you could transparently redirect to  
your XML checker.


> Here we corrected our claims, sorry for not keeping the comparison  
> up to date.

Appreciated.


>  > * http://www.validome.org/out/ena4011
> > HTML 4.01 document with no system Id.
> > Validome sends a warning... Not necessary per the spec.
> > W3C Markup validator passes validation.
> > Why is W3C validator marked as faulty here? References please?
>
> http://www.w3.org/TR/1999/REC-html401-19991224/struct/ 
> global.html#h-7.2
> Other way: Where is specified, that System-Id can be missed?

SGML, which HTML 4.01 is an application of.
Only in XML is the system identifier required, per:
http://www.w3.org/TR/xml/#NT-ExternalID


> > * http://www.validome.org/out/ena4023
> > Validome says valid. OpenSP and W3C Markup validator says not valid.
> > I'd tend to trust opensp here. The comparison page's claim that
>  validome is the only validator doing the right thing is very dubious.
>
> > * http://www.validome.org/out/ena4024
> > Ditto above. The comparison page's claim that validome is the only
> > validator doing the right thing is very dubious.
>
> What is here dubious? It's about SGML (not HTML) documents.

And?


> The "old" W3C-Validator made a fallback o US-ASCII, the "new" to  
> UTF-8. Can you explain this, please?
> We asked many times W3C-Germany and Bjoern Hoehrmann in regard to  
> the *correct* behaviour of an validator in the case of a fallback,  
> but we didn't get any *exact* answer. In this case, the specs are  
> very unexact and ambiguous. Please give us a *mandatory" answer -  
> with a link reference to appropriate specifications - upon this  
> case. The only clear case till now is XHTML, there validators  
> should make a fallback to UTF-8 (depending on MIME-Type), HTML is  
> still ambiguous...

There is no authoritative answer as far as I can tell, which supports  
my question: why do you consider your sending a fatal error the right  
thing to do, and other validators trying a fallback wrong? If there  
is no rule, you are not supposed to make arbitrary ones and claim you  
are the only ones to respect them.


> > * http://www.validome.org/out/ena7003
> > I'd like to see a reference for this.
>
> http://www.w3.org/TR/html401/struct/links.html#h-12.2.3
> "...The id attribute, on the other hand, may not contain character  
> references."

Interesting discrepancy between prose and DTD here, thanks for the  
pointer.


> > * http://www.validome.org/out/ena7005 (and 7006)
> > This has nothing to do with validation. If validome emulates some of
> > the features of a link checker, compare it to link checkers, not
> > validator. This test is moot.
>
> http://www.w3.org/TR/html401/struct/links.html#h-12.2.4
> "A reference to an unavailable or unidentifiable resource is an error"
> ...
> "If a user agent cannot locate a linked resource, it should alert  
> the user"
>
> Where is here the "moot"? The W3C-Specification is very clear in  
> this case...

This is the usual confusion between user agent conformance (which the  
sections you quote are about) and document conformance (which  
validome and the markup validator are checking).


>   * http://www.validome.org/out/ena3002
> > This test is bogus. Sorry. An XML declaration also happens to be a
> > proper SGML PI. Giving a warning asking the HTML4 author "are you
> > sure you want this here" may be a good idea. Making this a fatal
> > error is wrong, wrong, wrong.
>
> If a XML-declaration is allowed in SGML, I'd like to see a  
> reference for this.

What I have is the SGML spec, chapter 8. Processing instructions.


[on shorttags]
> Oh, her we have hundred opinions of the case. Could you please show  
> us a *exact* reference?

The best I have is the informative:
http://www.w3.org/TR/html401/appendix/notes.html#h-B.3.7
and the normative DTD, which allows the shorttags. As such, the spec  
clearly allows the construct, while informatively warning against it.


I'll reply to your notes on distributing the markup validator in a  
separate mail.

Thank you,
-- 
olivier
Received on Wednesday, 24 October 2007 04:28:35 GMT

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