[whatwg] Conformance checking using schemas (was: Re: [html5] tags, elements and generated DOM)

Ian Hickson ian at hixie.ch
Fri Mar 10 11:32:00 PST 2006

On Sun, 26 Feb 2006, Henri Sivonen wrote:
> On Feb 25, 2006, at 01:16, Ian Hickson wrote:
> > For the kind of detailed conformance checking HTML5 requires, you'll 
> > be wanting to use your own explicit hard-coded implementation, not one 
> > or more schemas. IMHO.
> Is there any particular reason why you think one wouldn't want to use 
> schemas?

Probably just my personal aversion to schemas.

> The downside I see is that error messages will be less precise than what 
> carefully crafted custom code would allow. However, I believe a 
> schema-based implementation to be easier to write, more maintainable, 
> more portable and better customizable (portable and customizable e.g. 
> for inclusion in a CMS that wants more restrictions on input).

Certainly implementations are free to use schemas if they desire, so long 
as the end result is compliant.

> My current plan is
> 1) to use RELAX NG for everything it is convenient for (element nesting,
> attribute occurrence, attribute datatypes through datatype libraries)
> 2) to use the XSD datatype library within RELAX NG for everything it is good
> for
> 3) to define (in English) and implement (in Java) a datatype library for stuff
> that the XSD library is not good for
> 4) to use Schematron for stuff that Schematron can cover but the above can't
> conveniently cover
> 5) to use custom Java code if there is still something that is not covered.

I look forward to hearing you describe your experiences with this.

Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'

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