• From: Philippe Poulard <Philippe.Poulard@s...>
• To: "Costello, Roger L." <costello@m...>
• Date: Fri, 24 Aug 2007 11:39:02 +0200

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,

              ///
             (. .)
 --------ooO--(_)--Ooo--------
|      Philippe Poulard       |
 -----------------------------
 http://reflex.gforge.inria.fr/
       Have the RefleX !

• References:
  • Backward and forward compatible schemas ... Relax NG --> Yes ... XML Schema --> No
    • From: "Costello, Roger L." <costello@m...>