Re: Bugzilla Issue: 4639 - Cyclic SML models

There is an SML validator implementation in the COSMOS open source project  and I am leading this team. 
We did not have any issue with supporting cycles at the element level as 
opposed to ( or complementing ) document cycles as described by the 
current specification. Our validator is using a file based SML repository 

To be honest, I think that what is missing here are the set of usecases we 
want to enable with this function. 

Thank you,
Valentina Popescu
IBM Toronto Labs
Phone:  (905)413-2412         (tie-line  969)
Fax: (905) 413-4850

"Smith, Virginia (HP Software)" <> 
Sent by:
06/25/2007 05:45 PM


Bugzilla Issue: 4639 - Cyclic SML models

This email is to start a discussion on document-based cycles vs.
element-based cycles in SML. 

In the current SML spec, there is a mismatch in that references are
defined as pointing to elements and model cycles are defined based on
documents. Since the concept is question (references) are based on
elements, it makes sense to me that SML model cycles should be defined
based on elements. 

I see 2 scenarios that pose a problem when testing for cycles according
to the current spec.

1) Since a reference can point to an element defined in the same
document as the reference, a cycle could exist within a single document
but not appear as a cycle in a document-based graph. (false negative)

2) Let's say Document A contains a reference to element X in Document B
and Document B contains a reference to element Y in Document A and
elements X and Y are not related in any way. This is not really a cycle
(of element references) but will appear as a cycle in a document-based
graph. (false positive)

I think we need to answer the following question:

- Are there implementation-related reasons to support document-based
graphs but not element-based graphs? (An SML validator implementation
must be realistically achievable.) 

Does anyone have experience with implementing an SML validator (or know
someone with relevant experience)? 


Virginia Smith 
HP Software / BTO R&D
8000 Foothills Blvd | Roseville | CA 95747 

Received on Tuesday, 26 June 2007 04:36:43 UTC