[DFDL-WG] Action 086 Nils and Default processing - draft 8

Wed Jul 7 08:51:51 CDT 2010

Further comments in this version:

regards,

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

From:
Stephanie Fetzer <sfetzer at us.ibm.com>
To:
Steve Hanson/UK/IBM at IBMGB
Cc:
dfdl-wg at ogf.org, dfdl-wg-bounces at ogf.org
Date:
07/07/2010 13:43
Subject:
Re: [DFDL-WG] Action 086 Nils and Default processing - draft 8

All: 

After reviewing the changes proposed by Steve I'm glad that my suggested 
mods were to be placed before the existing section (as he has changes 
everywhere!).  My suggestion would be  an introductory paragraph at the 
start of the section to set the stage for: 
 - why are we spending this whole section describing these concepts (why 
are they important) 
 - why are we starting with our own definitions of terms 
 - how do these concepts fit together 

I have some rough wording I'd like to start with for a proposal: 

Processing of nils and defaults for parsing and unparsing relies on 
several concepts and can be confusing unless explicitly described. We need 
to consider the content of the datastream or the infoset, the cardinality 
of the elements and sometimes their parents, and DFDL properties related 
to nill and default values as well as syntax such as initiators and 
terminators. 

For parsing we are looking at the incoming datastream and the DFDL 
properties to determine what gets built into the infoset.  This involves 
decisions such as: 
    If the data is not in the datastream does this equate to a default 
value, or a nill value, or nothing at all 
    in the created infoset?   

For unparsing we are looking at the infoset and the DFDL properties to 
determine what gets built into the output datastream.  This involves 
decisions such as: 
        If there is no value for an element in the infoset do we need to 
create the initiator and terminator in the datastream? 

We will start off by defining some terms which we will be used to make 
describing the rules a little clearer. 

If this is too 'light' for the spec we can always put in the 
tutorial/primer...but I wanted to get some amount of high level overview 
together while we were working through this. 

Regards, 
Stephanie Fetzer
WebSphere Common Transformation
Industry Packs - Software Engineer

From: 
Steve Hanson <smh at uk.ibm.com> 
To: 
Alan Powell <alan_powell at uk.ibm.com> 
Cc: 
dfdl-wg at ogf.org 
Date: 
07/07/2010 07:18 AM 
Subject: 
[DFDL-WG]  Action 086 Nils and Default processing - draft 8 
Sent by: 
dfdl-wg-bounces at ogf.org

Hi Alan 

I started to make comments but decided that it was easier to make changes 
directly, so that is what I did. Comments that remain are for things that 
need discussion (there's only a couple). 

I made a lot of changes including sorting out your bullet numbering but 
the main changes were: 

a) The 'If ... Else If' logic had gone badly astray, because of combining 
the non-initiator and initiator cases. It's not as compact as we thought 
but still better combined I think. 

b) "If 'is nil' with the content region as the empty string"  - the 
content region clause is redundant.  Your separate definition of 'is nil' 
combined with being in a 'missing element' branch of the logic, means just 
saying 'is ni' is sufficient. 

c) Definition of nil when unparsing - does not need the useNilForDefaults 
clause - nil and mssing are mutually exclusive when unparsing. The 
useNilForDefault property comes into play via 'has default'. 

Regards

Steve Hanson
Strategy, Common Transformation & DFDL
Co-Chair, OGF DFDL WG
IBM SWG, Hursley, UK,
smh at uk.ibm.com,
tel +44-(0)1962-815848 

From: 
Alan Powell/UK/IBM at IBMGB 
To: 
dfdl-wg at ogf.org 
Date: 
02/07/2010 15:34 
Subject: 
[DFDL-WG] Fw: Fw: Fw: Fw: Action 086 Nils and Default processing - draft 7 

Sent by: 
dfdl-wg-bounces at ogf.org

All 

Latest draft (v7 )of the nils and default document incorporating comments 
from this week. 

Please send comments before next WG call.

Still having problems with bulleted lists 

Regards 

Alan Powell 

Development - MQSeries, Message Broker, ESB 
IBM Software Group, Application and Integration Middleware Software 
------------------------------------------------------------------------------------------------------------------------------------------- 

IBM 
MP211, Hursley Park 
Hursley, SO21 2JN 
United Kingdom 
Phone: +44-1962-815073 
e-mail: alan_powell at uk.ibm.com

----- Forwarded by Alan Powell/UK/IBM on 02/07/2010 15:32 ----- 
From: 
Alan Powell/UK/IBM at IBMGB 
To: 
dfdl-wg at ogf.org 
Date: 
30/06/2010 13:05 
Subject: 
[DFDL-WG] Fw:  Fw:  Fw: Action 086 Nils and Default processing

All 

Latest draft of the nils and default document incorporating comments from 
last week. 

As you will see I have been having problems with bulleted lists in word 
which are still not correct but I assume I can fix for the spec. 

Regards 

Alan Powell 

Development - MQSeries, Message Broker, ESB 
IBM Software Group, Application and Integration Middleware Software 
------------------------------------------------------------------------------------------------------------------------------------------- 

IBM 
MP211, Hursley Park 
Hursley, SO21 2JN 
United Kingdom 
Phone: +44-1962-815073 
e-mail: alan_powell at uk.ibm.com

----- Forwarded by Alan Powell/UK/IBM on 30/06/2010 13:01 ----- 
From: 
Steve Hanson/UK/IBM 
To: 
Alan Powell/UK/IBM at IBMGB 
Date: 
25/06/2010 16:07 
Subject: 
Fw: [DFDL-WG] Fw:  Fw: Action 086 Nils and Default processing

Hi Alan - were you going to take the updates forward, or did you want me 
to make some changes first? 

Reviewed Steve's updates to the parsing and unparsing rules. 
- it might be possible to simplify the nil processing in the rules by 
having a defintion up front. 
-  'nil indicator set' need a definition 
- Discussion about whether 'usNilForDefaults' could be replaced by some 
way of defining a literal, out of band value for the default. 
- 'value' used when should be 'output value' 
- dfdl:emptyValueDelimietrPolicy description should be moved from 
defaulting section to initiator section. 
- 'text markup' used in section 14.2 of spec   

Regards

Steve Hanson
Strategy, Common Transformation & DFDL
Co-Chair, OGF DFDL WG
IBM SWG, Hursley, UK,
smh at uk.ibm.com,
tel +44-(0)1962-815848 
----- Forwarded by Steve Hanson/UK/IBM on 25/06/2010 16:00 ----- 
From: 
Steve Hanson/UK/IBM 
To: 
dfdl-wg at ogf.org 
Date: 
23/06/2010 11:18 
Subject: 
Re: [DFDL-WG] Fw:  Fw: Action 086 Nils and Default processing

Here's my latest updates.  As discussed I have reworked the 'Nils & 
Defaults on parsing/unparsing' sections. 

One question was thrown up.  On parsing when a required complex element is 
missing, we add it to the infoset as long as applying default processing 
to its missing children does not cause an error. You will see I have used 
the phrase 'Missing element processing is applied to all child elements.' 
to cover this.  But 'Missing element processing' as now spelled out in the 
same section includes 'nillable and empty string' processing when the 
child is simple. Does this apply here? 

[attachment "dfdl-nils-defaults-v5-SMH.doc" deleted by Alan Powell/UK/IBM] 

Regards

Steve Hanson
Strategy, Common Transformation & DFDL
Co-Chair, OGF DFDL WG
IBM SWG, Hursley, UK,
smh at uk.ibm.com,
tel +44-(0)1962-815848 
From: 
Steve Hanson/UK/IBM 
To: 
Alan Powell/UK/IBM at IBMGB 
Cc: 
dfdl-wg at ogf.org 
Date: 
16/06/2010 14:40 
Subject: 
Re: [DFDL-WG] Fw:  Fw: Action 086 Nils and Default processing

Hi Alan 

I've updated the document and added some comments. Still quite a bit to 
discuss. 

Regards

Steve Hanson
Strategy, Common Transformation & DFDL
Co-Chair, OGF DFDL WG
IBM SWG, Hursley, UK,
smh at uk.ibm.com,
tel +44-(0)1962-815848 
From: 
Alan Powell/UK/IBM at IBMGB 
To: 
dfdl-wg at ogf.org 
Date: 
02/06/2010 11:21 
Subject: 
[DFDL-WG] Fw:  Fw: Action 086 Nils and Default processing 
Sent by: 
dfdl-wg-bounces at ogf.org

I have updated based on last weeks call 

Regards 

Alan Powell 

Development - MQSeries, Message Broker, ESB 
IBM Software Group, Application and Integration Middleware Software 
------------------------------------------------------------------------------------------------------------------------------------------- 

IBM 
MP211, Hursley Park 
Hursley, SO21 2JN 
United Kingdom 
Phone: +44-1962-815073 
e-mail: alan_powell at uk.ibm.com

----- Forwarded by Alan Powell/UK/IBM on 02/06/2010 11:20 ----- 
From: 
Alan Powell/UK/IBM at IBMGB 
To: 
dfdl-wg at ogf.org 
Date: 
25/05/2010 17:27 
Subject: 
[DFDL-WG] Fw: Action 086 Nils and Default processing

All   

I have added unparsing and corrected some of the existing information in 
this latest version.   

I did attempt to write out the dfdl:nilValueDelimiterPolicy and 
dfdl:emptyValueDelimiterPolicy options in full but it became unreadable 
hence the 'as controlled by' short cut.   

Links still don't work   
Regards   

Alan Powell   

Development - MQSeries, Message Broker, ESB   
IBM Software Group, Application and Integration Middleware Software   
------------------------------------------------------------------------------------------------------------------------------------------- 

IBM   
MP211, Hursley Park   
Hursley, SO21 2JN   
United Kingdom   
Phone: +44-1962-815073   
e-mail: alan_powell at uk.ibm.com

----- Forwarded by Alan Powell/UK/IBM on 25/05/2010 17:22 -----   
From:   
Alan Powell/UK/IBM   
To:   
dfdl-wg at ogf.org   
Date:   
13/05/2010 17:28   
Subject:   
Action 086 Nils and Default processing

All   

Attached is an updated version of the nils and defaults sections of the 
specification. I have only completed the parsing section so far which you 
should be able to review while I am on vacation. If someone would like to 
add the unparsing section that would be great.   

Note that the cross references are not correct.   
Regards   

Alan Powell   

Development - MQSeries, Message Broker, ESB   
IBM Software Group, Application and Integration Middleware Software   
------------------------------------------------------------------------------------------------------------------------------------------- 

IBM   
MP211, Hursley Park   
Hursley, SO21 2JN   
United Kingdom   
Phone: +44-1962-815073   
e-mail: alan_powell at uk.ibm.com

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 

#### dfdl-nils-defaults v2.doc moved to MyAttachments Repository V3.8 (
Link) on 23 May 2010 by Alan Powell.   

Unless stated otherwise above: 
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741598.   
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 

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#### dfdl-nils-defaults v3.doc moved to MyAttachments Repository V3.8 (
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Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 

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#### dfdl-nils-defaults v4.doc moved to MyAttachments Repository V3.8 (
Link) on 08 June 2010 by Steve Hanson. 

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741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 

#### dfdl-nils-defaults-v4-SMH.doc moved to MyAttachments Repository V3.8 
(Link) on 22 June 2010 by Steve Hanson. 

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 

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741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU 

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