I am not sure about schema def errors caught at runtime. I think these are more serious and shouldn't cause backtracking. I don't think they should just convert to processing errors. 

Consider that some dfdl implementarions may not detect anything until runtime.  
 

...mikeb


On Oct 6, 2009, at 5:44 PM, Tim Kimber <KIMBERT@uk.ibm.com> wrote:


- I'd like to see a version in which the comments are addressed and removed.
- typo in para 1 : 'neatest'
- 'A point of uncertainty is caused'. Probably better to say that it is 'opened' or 'started'.
- para which begins 'For an optional element' has a repeated phrase towards the end.
- I was assuming that any processing error, of any kind, relating to any physical region, would cause backtracking to the nearest point of uncertainty.
If there is any set of processing errors that *doesn't* cause backtracking, that set should be described in this doc.
- Should have a statement about how validation errors affect points of uncertainty. I'm assuming that they don't ( either the parse is immediately stopped by the host application, or the validation error is ignored)
- Should have a statement about how schema definition errors, if detected by the DFDL parser, affect points of uncertainty. I'm assuming that they are treated exactly like a processsing error, and cause backtracking to occur in the normal way.

regards,

Tim Kimber, Common Transformation Team,
Hursley, UK
Internet:  kimbert@uk.ibm.com
Tel. 01962-816742  
Internal tel. 246742


From: dfdl-wg-request@ogf.org
To: dfdl-wg@ogf.org
Date: 06/10/2009 18:18
Subject: dfdl-wg Digest, Vol 38, Issue 2




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Today's Topics:

  1. DFDL Specification draft v1.036 available (Alan Powell)
  2. Parsing Rules for resolving points of uncertainty V2 (Alan Powell)


----- Message from Alan Powell <alan_powell@uk.ibm.com> on Tue, 6 Oct 2009 14:46:36 +0100 -----
To:
Subject:
[DFDL-WG] DFDL Specification draft v1.036 available



Draft 036 of the DFDL Specification V1 is available but unfortunately sourceforge seems to be having problems again so I cannot upload it. If you need a copy please send me an email.

Alan Powell

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

Unless stated otherwise above:
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----- Message from Alan Powell <alan_powell@uk.ibm.com> on Tue, 6 Oct 2009 18:16:59 +0100 -----
To:
Subject:
[DFDL-WG] Parsing Rules for resolving points of uncertainty V2



Updated proposal based on comments




Alan Powell

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

----- Forwarded by Alan Powell/UK/IBM on 06/10/2009 18:15 -----
From: Steve Hanson/UK/IBM
To: Tim Kimber/UK/IBM@IBMGB
Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia/Toronto/IBM@IBMCA, Mike Beckerle <mbeckerle.dfdl@gmail.com>, Peter Lambros/UK/IBM@IBMGB, steve.marting@progeny.net
Date: 30/09/2009 10:31
Subject: Re: Parsing Rules for resolving points of uncertainty (speculative         parsing)


Some more comments in here.

Steve copied in as will be discussed on call today.

[attachment "Resolving Uncertainty v1.doc" deleted by Alan Powell/UK/IBM]

Regards

Steve Hanson
Programming Model Architect, WebSphere Message  Brokers,
OGF DFDL WG Co-Chair,
Hursley, UK,
Internet: smh@uk.ibm.com,
Phone (+44)/(0) 1962-815848

From: Tim Kimber/UK/IBM
To: Mike Beckerle <mbeckerle.dfdl@gmail.com>
Cc: Alan Powell/UK/IBM@IBMGB, Suman Kalia <kalia@ca.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Robert Connolly <rconnoll@us.ibm.com>, Steve Hanson/UK/IBM@IBMGB
Date: 28/09/2009 14:20
Subject: Re: Parsing Rules for resolving points of uncertainty (speculative         parsing)


re: Mike's point, I would suggest
- member of a choice group/unordered group/group containing floating elements: scope of uncertainty is the scope of the element
- optional occurrence : parser tries first to parse another occurrence, and the scope of uncertainty is the scope of the element. Secondly, parser tries to parse the item following the element ( which may be a group ) and the scope of uncertainty is the scope of that element/group.

re: Alan's draft, I think the final para could be replaced with the following two statements:
- if a processing error is encountered while parsing an option, the parser will back up and try the next option. If there are no further options, the processing error will propagate out to the next enclosing point of uncertainty.
- a dfdl:assert can be used to trigger a processing error. If the expression evaluates to false, the parser will behave exactly as if a normal processing error had been encountered.

Wording can probably be improved...

regards,

Tim Kimber, Common Transformation Team,
Hursley, UK
Internet:  kimbert@uk.ibm.com
Tel. 01962-816742  
Internal tel. 246742
From: Mike Beckerle <mbeckerle.dfdl@gmail.com>
To: Alan Powell/UK/IBM@IBMGB
Cc: Steve Hanson/UK/IBM@IBMGB, Tim Kimber/UK/IBM@IBMGB, Robert Connolly <rconnoll@us.ibm.com>, Peter Lambros/UK/IBM@IBMGB, Suman Kalia <kalia@ca.ibm.com>
Date: 25/09/2009 21:53
Subject: Re: Parsing Rules for resolving points of uncertainty (speculative         parsing)



Some feedback attached.

We need some notion of the region of uncertainty, so we can discuss where assertions and discriminators have effect, and so we can say when the uncertainty ends and we no longer consider backtracking that region just because we finished without processing error.



On Fri, Sep 25, 2009 at 11:51 AM, Alan Powell <alan_powell@uk.ibm.com> wrote:

Guys  (limited distribution initially)


I have simplified the previous speculative parsing description into a set of simple rules.

Discussion points
1.        Deemed to be found rule 1 'All the components of the option are found' could severely limit the ability to do partial parsing as it includes everything up to the terminator.
2.        Do all/more the processing errors need to be listed for Not Found rule 3?




Alan Powell

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

Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU




[attachment "Resolving Uncertainty v1.doc" deleted by Tim Kimber/UK/IBM]

[attachment "Resolving Uncertainty v1.doc" deleted by Steve Hanson/UK/IBM]




Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU











Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU





[attachment "Resolving Uncertainty v2.doc" deleted by Tim Kimber/UK/IBM] --
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