W3C home > Mailing lists > Public > xmlschema-dev@w3.org > March 2007

Re: Schema 1.1: xs:anyEnumeration considered?

From: David Carver <kingargyle@gmail.com>
Date: Tue, 20 Mar 2007 11:10:54 -0500
Message-ID: <4600078E.4010400@gmail.com>
To: Pete Cordell <petexmldev@tech-know-ware.com>
CC: David Ezell <David_E3@VERIFONE.com>, xmlschema-dev@w3.org

First, I'll state that I'm just a consumer of the spec, so I'm not a 
work group member, but I do work for a B2B standards organization that 
use schema extensively.
>
> And, I think only a parent could think that the union trick is not 
> ugly :-)
>

Actually, it has it's good and bad points, but I don't necessarily think 
it is an ugly trick, just one that is not published enough or written 
about enough.   From my aspect, it takes educating my users about the 
extensibility and the various ways that it can be done.
> But what I don't like about the union trick is that I've never seen 
> anyone
> use it the first time they tried to make an extensible enumeration.  
> Schema
> is a beast to learn.  This problem is compounded by the fact that for 
> many
> developers only a tiny fraction of their time will involve developing
> schemas.  Hence they won't have the miles and miles of experience that 
> they
> have in the other languages they use day in-day out.  I think the WG 
> should
> recognise this by not requiring developers to use secret handshakes and
> incantations to avoid ending up hitting brick walls!  My concern is 
> that, by
> being the elite in schema develop (and probably among the elite of
> developers in general), the WG members don't fully appreciate these
> difficulties that lesser developers have with schema, and so dismiss 
> them as
> un-important.
I deal with people that don't care how the schema is created, as long as 
it doesn't affect there system and break their code.   The less they 
have to deal with it the better, it's why they have our organization 
create the schemas that they use.   The problem with extensibility is 
that it DOES create interoperability problems, no matter how you try to 
control it.   Once it is extensible, then you immediately have 
interoperability problems when somebody does a one off implementation of 
a schema.  Yes, you can do must understand and must ignore type logic, 
but experience has shown me that people don't do this.   They bind to 
the schema that they are given, and if that deviates from the industry 
standard schema, they don't know or care.

Extensibility has it's place, and with enumerations, I think the way it 
works now for enumerations is "good enough", not perfect but it gets the 
job done.   Anything else from my experience makes more interoperability 
problems not less.

Dave
Received on Tuesday, 20 March 2007 18:58:22 UTC

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