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Re: Schema 1.1: xs:anyEnumeration considered?

From: Pete Cordell <petexmldev@tech-know-ware.com>
Date: Tue, 20 Mar 2007 14:13:30 -0000
Message-ID: <00fa01c76afa$13f46320$c900a8c0@Codalogic>
To: "David Ezell" <David_E3@VERIFONE.com>, <xmlschema-dev@w3.org>

My apologies - This posted before I was ready (finger trouble!)

There's a fuller reply (much, much fuller!) to come!

Thanks again,

----- Original Message ----- 
From: "Pete Cordell" <petexmldev@tech-...>
To: "David Ezell" <David_E3@...>; <xmlschema-dev@w3...>
Sent: Tuesday, March 20, 2007 12:00 PM
Subject: Re: Schema 1.1: xs:anyEnumeration considered?

> ----- Original Message ----- 
> From: "David Ezell" <David_E3@...>
> To: <xmlschema-dev@...>
> Sent: Monday, March 19, 2007 10:06 PM
> Subject: Re: Schema 1.1: xs:anyEnumeration considered?
>> Like Noah, I'm not speaking for the WG.  However, I am a WG member
>> with a keen interest in extensibility, so I feel like I should weigh
>> in here.  (Let me start by saying that as a WG member I'm very pleased
>> to have get this kind of feedback.  Don't let the fact that I disagree
>> in this particular case make anyone think I'm unappreciative. :-)
>> As a WG member, I consciously decided >not< to lobby for this
>> feature, which I'll call "simplistic enumeration extension", or
>> SEE from now on.  In terms of what we think of extensibility, it
>> runs contrary to other mechanisms in that it allows information
>> that's totally unexpected to appear in a field.  In other
>> extensibility mechanisms that have been proposed (like our
>> enhanced wildcard formulations or even type derivation) a na´ve
>> application will at least have >some< familiar data to work with
>> even if the unexpected appears.
>> My experience at NACS (National Association of Convenience Stores)
>> as chair of a working group working on XML languages is as follows:
>> In the previous version of our languages, our members insisted
>> on extensibility of enumerations, so we used the "trick" with
>> xs:union you mentioned (it's really not all that ugly :-) throughout
>> our language, litterally dozens of enumerations.  Our overwhelming
>> experience is that such extensions break interoperability in ways
>> that other kinds of extension don't, so we're removing the construct
>> entirely from the next version of our languages.
>> Therefore, as a WG member I've not lobbied for SEE.  To be fair, I
>> did at one point lobby for a truly extensible enumeration (i.e. with
>> a predefined way to identify a well-known fallback value to that
>> na´ve applications can continue) but the WG has not had time to
>> consider this kind of mechanism.  I'd actually advise against SEE
>> because 1) it's misleading in terms of interoperability, and 2)
>> the "ugly" alternative really isn't that bad.
> My $0.02.
> Best regards,
> David
> Pete.
> --
> =============================================
> Pete Cordell
> Tech-Know-Ware Ltd
> for XML to C++ data binding visit
> http://www.tech-know-ware.com/lmx/
> http://www.codalogic.com/lmx/
> =============================================
Received on Tuesday, 20 March 2007 14:15:21 UTC

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