[whatwg] [WF2] Web Forms 2.0: Repetition and type ID

Robin Berjon robin.berjon at expway.fr
Sun Jul 3 16:42:28 PDT 2005

Ian Hickson wrote:
> On Fri, 1 Jul 2005, fantasai wrote:
>>While we're on the topic.. what sorts of things would HTML5 conformance 
>>checkers have to do that is impossible to express in schema languages? 
>>(Aside from checking semantic correctness, of course. I hope you aren't 
>>expecting that from a piece of software.)
> Examples, assuming we are just talking about the XML version of HTML5 and 
> not the "HTML" version (for lack of a better name):
>  * checking the MIME type of the file
>  * there must not be more than one <dfn> per term
>  * some of the more exotic content models, e.g. <ins>, <del>, the 
>    distinction between inline-level containers and block-level containers
>  * checking conformance of <meta> elements (requires parsing a profile)
> ...and of course:
>  * IDs may contain any characters, not just those allowed in XML IDs.

Amongst the tools that have been mentionned was Schematron. Out of the 
box Schematron can't check a media type, but with a very trivial to 
write extension function it could. All the rest that you mention seems 
very much doable. Schematron is built on XPath, which is a very useful 
and powerful little language.

> There are also things which will probably require warnings from 
> conformance checkers, e.g. violations of SHOULD requirements, including 
> e.g. making sure the appropriate <hx> header is used in sections.

Schematron can warn. You could even define warning levels and optionally 
look for a lot of issues, even just provide some informative messages 
for what might be bad practices.

>>Generic XML editors like XXE have support for using a schema to guide 
>>the editing process, but have no knowledge specific to a given language 
>>like XHTML. These tools, and other generic XML tools, will not be able 
>>to recognize the IDness of the 'id' attribute if it's not possible to 
>>express this in a schema.
> As mentioned, that will be the least of their problems.

No, fantasai is right, I can see this being a FAQ, for no obvious 
technical reason.

> Sigh. Can someone please explain why there is a completely ridiculous 
> restriction on the values of IDs???

IDs are names. I don't like the restriction either but it's there and 
I'd much better handle it than ignore it. In fact, since it's a 
restriction inherited from SGML HTML-the-SGML-application has it as 
well, it just so happens that that's not the way most recent browsers 
have implemented it.

> Next I was going to use U+02AD .. U+02AC, but since these are new 
> characters, they're only in XML 1.1, not XML 1.0. I presume _that_ is a 
> problem for everyone as well?

I have no problem relying on XML 1.1 characters, I would say go ahead so 
long as they are name chars.

> I didn't 
> want to use ":" at all because of the way that character has special 
> meaning for namespaces these days.)

"These days" being six years by now, striving and succesful, I think we 
just have to live with it :)

Robin Berjon
   Senior Research Scientist
   Expway, http://expway.com/

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