Re: [relax-ng] Re: Some ideas about type-assignment

["MURATA Makoto (FAMILY Given)" <EB2M-MRT@asahi-net.or.jp>]

> It seems to me that there are many different levels of type-assignment.

Yes, indeed.

> The first, easier level would be just determine declarations for
> elements, attributes, and possibly for texts. This can be done easily
> and useful for things like schema-guided editor or XQuery.

I think that many applications require this level.  In fact, Jonathan 
requires this level.

> For it to be useful for data-binding tools, I think what we need is
> "start-end detection" (for lack of better word) where the receiver would
> like to know when a new primitive starts and when it ends.
snip
> This is pretty much what RelaxNGCC does internally (so as JAXB RI), and
> I believe the algorithm is the same for Relaxer as well.

Agreed.  RelaxNGCC and Relaxer need to know which subpattern matches which 
subsequence (i.e., start-end) of element or attribute.  Although they 
impose different restrictions on RELAX NG grammars and use different algorithms for 
type-assignment, they both perform "start-end detection".

However, we cannot perform such "start-end detection" if we normalize schemas 
as specified in the RELAX NG spec.  In my understanding, neither Relaxer nor 
RelaxNGCC perform such normalization.

If our type-assignment spec has to provide "start-end detection", we will probably 
have to define semantics of RELAX NG schemas without performing normalization.  
I think that this is too difficult.  Rather, I think that "start-end detection" 
should be built by implementors of data binding tools.

In my understanding of Jonathan's message, XQuery does not require "start-end 
detection".  I thus propose to omit two of the requirements in my 
message [1]

> 
> - Type-assignment should be useful for data binding tools.
...
>   3) uniquely determine which group/interleave/choice is applied
>      to the content of each element and the value of each attribute, 
>      and

[1] http://lists.oasis-open.org/archives/relax-ng/200208/msg00012.html
-- 
MURATA Makoto (FAMILY Given) <EB2M-MRT@asahi-net.or.jp>