Re: Make its:param optional?

On 11.10.2012 16:30, Felix Sasaki wrote:
> ok ... but what to do about CSS  selectors? How does its:param interact
> with these? We just end up with a lot of combinations of ITS processors:

its:param is disallowed for CSS, see section 5.3.5:

"Implementation MUST support the param element for all query languages
it supports and which at the same time define how variables are bind for
evaluation of selector expression."

CSS doesn't define variable binding (at least current version of CSS,
there is some new work on adding variables into CSS), so its:param has
no effect on CSS selectors when queryLanguage="css"

> implements global rules and XPath 1.0
> implements global rules with XPath 1.0 and param
> implements global rules and XPath 2.0
> implements global rules with XPath 2.0 and param
> implements global rules using CSS
> implements global rules using CSS and param
> 
> I'm not so much worried about the implementation choices - a well
> documented implementation will make the choice clear -, but rather about
> re-usage of rules across implementations. With ITS 1.0, each rule could
> easily be re-used, because there is just one conformance class: global
> rules. With the above, in fact we have six classes.

As XPath 1.0 is default query language I think that it will be
prevailing QL, and that reasonable ITS users will not use something
different. While its:param can be useful, it addresses very specific
needs so it will not be extensively used IMHO. So in practice I think
that we will have similar interop as with ITS 1.0.

> Also, how to tell rule authors what of the choice the best practice is? Or
> in summary, the flexibility creates drawbacks on the rule re-usage and best
> practices side ...

The best practice is XPath 1.0 without params. We might issue updated
I18NBP document once ITS 2.0 is REC.

    Jirka

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