[DFDL-WG] Fw: DFDL Discriminators discussion

[Alan Powell]

Steve, Tim and I discussed discriminators so more, particularly 
transferring the WTX model to dfdl.

We think we were successful and cam up with the following semantics

A dfdl:discriminator resolves the presence of its parent group (sequence 
or choice). Note this isn't necessarily a point of uncertainty
If the parent group is the content model for a complex types then the 
instance of the element of the complex type also exists (that is: if the 
group is only defining the content of a complex element then the 
discriminator propagates from the group to the element automatically)


Alan Powell

 MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
 Notes Id: Alan Powell/UK/IBM     email: alan_powell at uk.ibm.com 
 Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898

----- Forwarded by Alan Powell/UK/IBM on 09/12/2009 12:51 -----

From:
Alan Powell/UK/IBM at IBMGB
To:
dfdl-wg at ogf.org
Date:
24/11/2009 15:50
Subject:
[DFDL-WG] DFDL Discriminators discussion



Following on from Stephanie's WTX example on last weeks call I think that 
restricting discriminator to resolving their parents provides the level of 
control that we need. 

I have updated Mike's example with this syntax  


Note I have flattened the schema as I find that easier to read and 
'enhanced' some the the dfdl properties. 

To illustrate the flexibility if  'L' had a test="{ fn:exists( . ) }" 
discriminator then if an L record had been found then the parse would fail 
rather than backtracking to Blob. 


Alan Powell

MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
Notes Id: Alan Powell/UK/IBM     email: alan_powell at uk.ibm.com  
Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898

 

 



 

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#### testDiscriminator2.dfdl.xml moved to MyAttachments Repository V3.8 () 
on 02 December 2009 by Alan Powell.






Unless stated otherwise above:
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741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU





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