Re: [xml-dev] Backward and forward compatible schemas ... RelaxNG --> Y

[Philippe Poulard <Philippe.Poulard@sophia.inria.fr>]

Costello, Roger L. a écrit :
> Hi Folks,
>  
> I am trying to characterize the types of changes to schemas which
> enable backward and forward compatibility.
>  
> [Definition] An old and new schema are backward and forward compatible
> with the other if each can validate XML instance documents that were
> written to the other schema.  Thus, a new application can process XML
> instances from an old application, and an old application can process
> XML instances from a new application.
>
> Assertion: Relax NG supports backward and forward compatibility but XML
> Schemas does not.
>   
hi Roger,

old schema :
(a|b)*
new schema :
(b|a)*

I'm almost sure that one can express these simple content models with 
WXS and RNG :)

IMHO, changes to schemas which enable backward and forward compatibility 
lead to 2 equivalent schemas (as they are validating the same instances)

-- 
Cordialement,

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|      Philippe Poulard       |
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