Certainly having dummy empty sequence with
leadingSkip before a repeating element having such requirement
is another option model developer can use. Let's not handle this
property differently and keep the spec the way it is right now..
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 <smh@uk.ibm.com>
To:
Suman Kalia/Toronto/IBM@IBMCA,
Cc:
dfdl-wg@ogf.org
Date:
10/17/2012 04:33 AM
Subject:
Re: [DFDL-WG]
Spec: Leading skip applied to every repeat of a repeating
element [s]
It is certainly true that the DFDL philosophy
is that you wrap a repeating element if you want to specify framing that
applies to the array as a whole. Array separator, initiator, terminator,
leadingSkip, alignment and trailingSkip are all consistent in this respect,
so it does seem wrong to change leadingSkip to behave in a different way.
For leadingSkip, there is an alternative to wrapping the repeating element
in a sequence, you could instead insert an empty sequence immediately before
the repeating element.
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 <kalia@ca.ibm.com>
To: Steve
Hanson/UK/IBM@IBMGB
Cc: dfdl-wg@ogf.org,
dfdl-wg-bounces@ogf.org
Date: 16/10/2012
23:03
Subject: Re:
[DFDL-WG] Spec: Leading skip applied to every repeat of a repeating
element [s]
The DFDL approach will work for COBOL case but it would require wrapping
the repeating element having such alignment requirement in a dummy
sequence. Not very good from a logical model point of
view but certainly will be consistent with other DFDL properties..
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: Mike
Beckerle <mbeckerle.dfdl@gmail.com>
To: Steve
Hanson/UK/IBM@IBMGB
Cc: dfdl-wg@ogf.org
Date: 16/10/2012
13:45
Subject: Re:
[DFDL-WG] Spec: Leading skip applied to every repeat of a repeating element
[s]
Sent by: dfdl-wg-bounces@ogf.org
I would assume that the skip properties are not array-oriented, as they
don't have "occurs" in their name. Hence, they apply to each
element instance in the same way as lengthKind and encoding and other non
"occurs" properties.
....mike
From: Steve
Hanson <smh@uk.ibm.com>
To: dfdl-wg@ogf.org,
Date: 10/16/2012
04:18 AM
Subject: [DFDL-WG]
Spec: Leading skip applied to every repeat of a repeating
element [s]
Sent by: dfdl-wg-bounces@ogf.org
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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