Re: [ubl-dev] Re: [xml-dev] Re: [ubl-dev] UBL 2.0 and Schema Extensibility

["G. Ken Holman" <gkholman@CraneSoftwrights.com>]

At 2006-05-18 13:57 +0100, Fraser Goffin wrote:

>let me check something so that I'm sure we are not talking at cross purposes.

Sounds good.

>I am talking about the validation of content within any extensibility
>point allowed in a schema (any schema, not just UBL) being performed
>by the parties that have apriori knowledge of what their expectations
>of that content should be (they each have a schema that describes it).

Well, individual parties would expect what is in an extension, but 
governing bodies would probably not ... nor should they want to.

>I was starting to get the feeling in this last discourse that you were
>talking about what you would expect a 'UBL aware' validation approach
>should be and what 'it' should reasonably know about or not.

Indeed ... we are publishing a standard for open use without 
governing anything about extensions beyond the influence they have in 
our schemas which is limited to their apex elements being direct 
children of our extension point.  The rest is their business, not the 
business of UBL.

>In this
>case I would agree that any validator that is only concerned with
>compliance to UBL should have no knowledge of other 'stuff' that may
>be put into one of its opaque containers ?

Great ... then we agree.

>Just checking :-)

:{)}

>This still leaves us with the choice of value for the processContent
>attribute of course.

I don't think it leaves us a choice at all ... as you say "UBL should 
have no knowledge of other 'stuff' that may be put into one of its 
opaque containers" ... which includes stuff that might be using UBL 
constructs for their own purpose.  Extension stuff is anyone else's 
purview, so the governing body better not interfere by saying 
anything at all about the content of extensions below the apex.

Again, the apex points cannot be UBL constructs because there is 
nothing wrapping the UBL constructs to say how they are to be treated 
as an extension.

>>Only the apex of the extension, the immediate child of the UBL
>>extension point, has to be non-UBL.  What is in each subtree under
>>each apex being an immediate child of the extension point is free
>>game ... including any bad practices or conflicting interpretations
>>... after all, the extender used the extension point to get away from
>>the standardized schema ... why pollute that environment by saying
>>"well, though you are in charge of your extension I'm still going to
>>impose this on you that you pass my other constructs however you use
>>them"?  The more I try to describe this, the more certain I feel about this.
>
>H'mmm, ok, I'm starting to understand where you're coming from here.
>Educate me a bit here. Is UBL defined principally of global
>elements/types ?

I think that's an orthogonal question, but yes UBL does follow the 
"Garden of Eden" characterization of schema expression where all 
elements and types are defined globally and there are no anonymous 
types.  Other characterizations of schema design patterns are termed 
"Russian Doll" (document element is global, all other local, all 
types local), "Salami Slice" (all elements global, all types local) 
and "Venetian Blind" (document element is global, all other local, 
all types global).

One of our many reasons to thank Eve Maler:

  http://www.idealliance.org/papers/xml02/dx_xml02/papers/05-01-02/05-01-02.html

I hope this helps.

. . . . . . . . . . . . Ken

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