RE: [ubl] Proposed withdrawal of my NDR suggestions for ABIE extensibility

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

At 2006-06-20 13:20 -0700, Sylvia Webb wrote:
>Does this mean that there can be no future minor versions of UBL 2.0?

Not at all, Sylvia, thankfully ... I interpret 
David Orchard's general recommendations for XML in a UBL context as follows:

(1) - we leave in the UBL 2 namespace for future minor versions of UBL 2.x

(2) - any new minor versions add only optional 
constructs and don't change any existing optional constructs to mandatory

(3) - applications ignore constructs that are in 
the UBL 2 namespace that does not recognize

(4) - item (3) is supported by a 
translate-before-validate process of stripping a 
document of unexpected constructs so that 
applications don't have to deal with information items they are not expecting

Items (3) and (4) address Jon's concerns 
regarding applications being backward compatible 
and not having to change when minor versions are released.

Item (3) does not address Paul Thorpe's issue 
regarding heterogeneous network validation 
environments for different versions of document 
models, unless (4) is implementable in his environment to avoid the problem.

And I think that (1) and (2) are supported by the 
existing NDRs, though I'm now looking for chapter 
and verse in order to answer your qeustion.  I 
note in 2006-05-25 the sentence on lines 687-689: 
"The schema set is the versioned entity, all 
schema modules within that package are of the 
same version, and each version has a unique 
namespace" ... I'm assuming that is major version 
and not minor version.  Lines 697/698 are 
unambiguous about major versions, but I don't see 
anything explicit regarding minor versions.  Ah, 
found it ... line 819 is explicit regarding minor versions.

I don't see (3) or (4) as NDRs ... they are 
implementation guidelines (the leftover subject of my discussion paper).

So, our minor versions (say 2.1) can introduce 
new optional elements at the end of ABIEs because 
legacy UBL applications (say 2.0) will ignore their presence.

As mentioned before, though, this process will 
produce "false positives" in that a 2.0 system 
that ignores 2.1 constructs for backward 
compatibility will equally ignore 
incorrectly-structured or improperly-named 2.1 
constructs since these are not being validated or 
checked.  They would, then, successfully treat 
the 2.0 information in an invalid 2.1 instance 
without reporting any 2.1 errors.  I think we can 
live with that, since there is no way of knowing 
if an unrecognized construct is supposed to be in a unknown document model.

Does this help, Sylvia?

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

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