RE: [xml-dev] Is there a way to reuse and extend an enumeration in XML schema

["Chiusano Joseph" <chiusano_joseph@bah.com>]

<Quote>
And as an aside, is there anything "substitutionGroup" does that "redefine" can't do better?
</Quote>

One large difference between the 2 approaches is that "redefine" requires that the new schema constructs (i.e. those the result from redefining an existing schema construct) belong to the same target namespace as the constructs that are being redefined, or that the new schema constructs are in no namespace. "substitutionGroup" has no such requirement.

In that regard, one might consider substitutionGroup to be more "flexible".

Kind Regards,
Joseph Chiusano
Booz Allen Hamilton
Strategy and Technology Consultants to the World
 

> -----Original Message-----
> From: William J. Kammerer [mailto:wkammerer@novannet.com] 
> Sent: Monday, March 07, 2005 7:25 PM
> To: XML Developers List
> Subject: Re: [xml-dev] Is there a way to reuse and extend an 
> enumeration in XML schema
> 
> Thanks. That sounds much like the proposed solution in §4.6, 
> Code List Schema Usage, in Universal Business Language (UBL) 
> Code List Representation (Version: 1.1 draft 17 January 
> 2005), at 
> http://lists.oasis-open.org/archives/ubl-dev/200502/pdf00000.p
> df.  But that one relied on "substitutionGroup" and would 
> have required changes to the published UBL schemas (e.g., 
> abstract="true" and some extra derivations).
> 
> I'm reading you to say that "redefine" is not a dead-end  
> approach.  UBL still has the requirement that document 
> instances be validated against the authority code list, if 
> those instances refer to the published schemas.  But the top 
> level schema could be a relatively small "wrapper"
> schema that could be replaced in toto by the user's wrapper 
> (modeled after UBL's wrapper) when any of the code lists had 
> to be modified.
> 
> Does anyone have examples of such redefinition? - or want to 
> make some using UBL's schemas?  And as an aside, is there 
> anything "substitutionGroup" does that "redefine" can't do better?
> 
> William J. Kammerer
> Novannet
> Columbus, OH 43221-3859 . USA
> +1 (614) 487-0320
> 
> ----- Original Message -----
> From: "Henry S. Thompson" <ht@inf.ed.ac.uk>
> To: "William J. Kammerer" <wkammerer@novannet.com>
> Cc: "XML Developers List" <xml-dev@lists.xml.org>
> Sent: Monday, 07 March, 2005 08:18 AM
> Subject: Re: [xml-dev] Is there a way to reuse and extend an 
> enumeration in XML schema
> 
> 
> W3C XML Schema v.1 does not provide for redefinition-in-place of
> simple types by extension, as it were.
> 
> It only provides for redefinition-in-place by restriction.
> 
> It follows that the only way to achieve redefinition-in-place of
> codelists is to initially define the codelist type as an unconstrained
> NMTOKEN, and redefine _that_ by restriction at deployment time.
> 
> That then would allow local extension by changing the redefinition.
> 
> In other words, published schema uses synonym for NMTOKEN as
> codelisttype, and then redefines that restricting it to the desired
> enumeration in a wrapper schema, which is what people actually use.
> 
> Those needing a larger code list use a different wrapper schema which
> redefines using their larger list.
> 
> In haste, hope this helps as a sketch,
> 
> ht
> -- 
>  Henry S. Thompson, HCRC Language Technology Group, University of
> Edinburgh
>                      Half-time member of W3C Team
>     2 Buccleuch Place, Edinburgh EH8 9LW, SCOTLAND -- (44) 
> 131 650-4440
>             Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk
>                    URL: http://www.ltg.ed.ac.uk/~ht/
> [mail really from me _always_ has this .sig -- mail without 
> it is forged
> spam]
> 
> 
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