W3C home > Mailing lists > Public > public-html@w3.org > March 2010

Re: Schemas and validation

From: Krzysztof Maczyński <1981km@gmail.com>
Date: Tue, 2 Mar 2010 13:41:44 +0100
Message-ID: <9468479E774A49339364F1F1DCCBF9E8@kmPC>
To: "Maciej Stachowiak" <mjs@apple.com>
Cc: <public-html@w3.org>
>> But it's a common problem, so people should be encouraged to  
>> validate. Being valid is supposed to enhance forward compatibility,  
>> so authors who consider W3C trustworthy will care about it. Valid  
>> markup is also more consistent and provides nice invariants for  
>> development of content and dependent standards. I'm sure that you, a  
>> prominent Mozilla developer, could give more advantages off the top  
>> of your head than me, a humble author.
>
> Validation is a good practice, but it's not a substitute for testing.  
> Just as running "lint" or "gcc -W -Wall" on your C++ code is a good  
> practice, but not a substitute for testing.
Of course. As Knuth said:
> Beware of the above code. I have only proven it correct, not tested it.
That doesn't invalidate my points though. But there seems to be some prejudice in the WHATWG against formal methods and machine processability. And I consider it important and helpful for authors (including myself) to provide as much of requirements as feasible in a form usable by computers. Or do you believe users are likely to forgo automation, read the prose in the spec, turn it mentally into an algorithm and perform validation by looking at a document?
Some formal method of assesing compliance (partially, I know, that's why validity is a narrower technical term) will be needed in authoring tools too.
One final thought: validation _is_ a form of testing. Browsers may consume tag soup because they're usually the last piece of software before content gets to the user. But for other types of user agents it's reasonable most of the time to test for validity before even attempting to feed a document itno that tool.

Best regards,

Krzysztof Maczyński
Received on Tuesday, 2 March 2010 13:35:25 UTC

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