Need confirmation from the DFDL WG as to the purpose of the leadingSkip property. The grammar says that leadingSkip applies to all occurrences of an array element.  Suman has indicated (below) that his intent for the property was to apply to the array as a whole.  The DFDL approach for 'array as a whole' properties is to carry them on a wrapper sequence, not the element itself.

Regards

Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair,
OGF DFDL Working Group
IBM SWG, Hursley, UK

smh@uk.ibm.com
tel:+44-1962-815848

----- Forwarded by Steve Hanson/UK/IBM on 16/10/2012 09:02 -----

From:        Suman Kalia/Toronto/IBM@IBMCA
To:        Steve Hanson/UK/IBM@IBMGB
Cc:        Alex Wood1/UK/IBM@IBMGB
Date:        15/10/2012 22:58
Subject:        Re: [Work Item 9791] Spec: Leading skip applied to every repeat of a repeating element [s]



I intended the behavior of leading and trailing skip counts for repeats to be same as in  MRM.    I can't say for sure if this would break anything in PL/1 as we have not implemented but certainly this behavior is required for COBOL..  We can discuss this in workgroup and if everyone agrees add it to  Errata..

Suman Kalia
IBM Canada Lab
WMB Toolkit Architect and Development Lead
Tel: 905-413-3923 T/L 313-3923
Email: kalia@ca.ibm.com

For info on Message broker
http://www.ibm.com/developerworks/websphere/zones/businessintegration/wmb.html





From:        Steve Hanson/UK/IBM@IBMGB
To:        Suman Kalia/Toronto/IBM@IBMCA,
Cc:        Alex Wood1/UK/IBM@IBMGB
Date:        10/15/2012 01:24 PM
Subject:        Re: [Work Item 9791] Spec: Leading skip applied to every repeat of a repeating element [s]



Does that mean in MRM that we have asymmetric behaviour between leadingSkip and trailingSkip ?  I'm reading that for MRM leading skip was just for first element, but trailing skip is for every repeat.  That's not how the DFDL grammar says things work - it applies leading skip to every repeat.

Regards

Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair,
OGF DFDL Working Group
IBM SWG, Hursley, UK

smh@uk.ibm.com
tel:+44-1962-815848





From:        Suman Kalia/Toronto/IBM@IBMCA
To:        Steve Hanson/UK/IBM@IBMGB
Date:        15/10/2012 15:18
Subject:        Re: [Work Item 9791] Spec: Leading skip applied to every repeat of a repeating element [s]



I am travelling and offsite and cannot access the RTC..  

Yes trailing skip count get applied to every repeating element.. this is the same semantic we have in MRM.. In COBOL terms , these are slack bytes which are added at the end of the structure if required.  

Suman Kalia
IBM Canada Lab
WMB Toolkit Architect and Development Lead
Tel: 905-413-3923 T/L 313-3923
Email: kalia@ca.ibm.com

For info on Message broker
http://www.ibm.com/developerworks/websphere/zones/businessintegration/wmb.html




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