Re: [xml-dev] Feasibility of "do all application coding in the XMLlangua

[Rick Jelliffe <rjelliffe@allette.com.au>]

Costello, Roger L. wrote:
>
>> http://www.w3.org/TR/xmlschema-patterns/
>>
>> The gist is in Appendix F
>>     
>
> Thanks Rick! 
>
> Let me see if I understand correctly:
>
> Want to create an XML Schema that is broadly adopted?
>
> Some of your users will use data binding tools to map the XML Schema constructs into data structures in an imperative programming language?
>
> Then don't use any of the XML Schema constructs listed below.
>   
Yes.The abstract says "This specification provides a set of basic [XML 
Schema 1.0] <http://www.w3.org/TR/xmlschema-patterns/#XMLSchema> 
patterns known to be interoperable between state of the art databinding 
implementations." 

I would say "check whether your implementation supports these elements" 
or "substitute less strong requirements" (e.g. use built-in primitives 
rather than built-in derived types.)  "Don't use these" is not 
necessarily the can-do response.

Also, one of the points is that some elements are only used in some 
circumstances or with certain values (hence all those patterns), so it 
is not as easy as simply ruling some in and some out.  (For example, 
IIRC at one stage there was talk that maxOccurs should only be 1 or 
unbounded (sorry I didn't check this) because implementations may 
implement a value maxOccurs="1000" by reserving 1000 objects or rows or 
whatever, blowing out memory I guess.)

Some of them are surprising. For example, <all> is just a trivial 
transform of a sequence with optionality, that is allowed. So I am 
really surprised that it is in the poo-pile.

Cheers
Rick Jelliffe