RE: [w3c sml] Bugzilla Issue: 4639 - Cyclic SML models

To answer the 2 questions, I posed in the original email - I've spoken
to an engineer at HP who worked on an SML validator project last year.
He does not see any technical problems in implementing cycles based on
elements instead of (or in addition to) cycles based on documents. This
verifies Valentina's comment.
 
--
ginny
 
---------------------
Virginia Smith
HP Software / BTO R&D
916-785-9940
8000 Foothills Blvd | Roseville | CA 95747
www.hp.com/software



 
________________________________


From: public-sml-request@w3.org [mailto:public-sml-request@w3.org] On
Behalf Of Valentina Popescu
Sent: Tuesday, June 26, 2007 12:36 AM
To: Smith, Virginia (HP Software)
Cc: public-sml@w3.org; public-sml-request@w3.org
Subject: Re: Bugzilla Issue: 4639 - Cyclic SML models


There is an SML validator implementation in the COSMOS open source
project http://www.eclipse.org/cosmos/ <http://www.eclipse.org/cosmos/>
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 implementation. 

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)" <virginia.smith@hp.com> 
Sent by: public-sml-request@w3.org 

06/25/2007 05:45 PM 

To

<public-sml@w3.org> 

cc

 

Subject

Bugzilla Issue: 4639 - Cyclic SML models

 

 

 





This email is to start a discussion on document-based cycles vs.
element-based cycles in SML.
http://www.w3.org/Bugs/Public/show_bug.cgi?id=4639 

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)? 


--
ginny

-------------------------------------------
Virginia Smith 
HP Software / BTO R&D
916-785-9940
8000 Foothills Blvd | Roseville | CA 95747
www.hp.com/software