[DFDL-WG] Agenda for OGF DFDL WG call 29 September 2010 15:00UK (10:00 ET)

Alan Powell alan_powell at uk.ibm.com
Tue Sep 28 11:33:50 CDT 2010


1. Current Actions 


Current Actions: 
No
Action 
066
Investigate format for defining test cases 
25/11:IBM to see if it is possible to publish its test case format. 
04/12: no update 
... 
17/02: IBM is willing in principle to publish the test case format and 
some of the test cases. May need some time to build a 'compliance suite' 
24/03: No progress 
03/03: Discussions have been taking place on the subset of tests that will 
be provided. 
10/03: work is progressing 
17/03: work is progressing 
31/03: work is progressing 
14/04: And XML test case format has been defined and is being tested. 
21/04. Schema for TDML defined. Need to define how this and the test cases 
will be made public 
05/05: Work still progressing 
12/05: Work still progressing 
02/06: Work still progressing on technical and legal considerations 
... 
25/08: Will chase to allow Daffodil access to test cases.   The WG should 
define how implementation confirm that they 'conform to DFDL v1' 
01/09: IBM still progressing the legal aspect. Intends to publish 100 or 
so tests as soon as it can, ahead of a full compliance suite. 
08/09: IBM still progressing 
15/09: IBM still progressing, expect tests to be available within a few 
weeks 
22/09: IBM still progressing, expect tests to be available within a few 
weeks 
085
ALL: publicise Public comments phase to ensure a good review.. 
14/04: see minutes 
21/04: Press release, OMG and other standards bodies. 
05/05: Alan and Steve H have contacted other standards bodies. Will ask 
them to add comments on spec 
15/05: still no public comments 
02/06: No public comments 
16/06: Public comments period has ended with no external comments. Alan 
had posted changes made in draft 041. Steve suggested send a note to the 
WG highlighting these changes.  Steve also suggested requesting an 
extension as other IBM groups may review. We discussed whether this was 
necessary as changes will need to be made during the implementation phase 
anyway. Alan to ask OGF what the process is for changes post public 
comment. 
23/06: Still no comments. Alan will contact OGF to understand the rest of 
the process. 
30/06: Alan has emailed Joel asking what the process is now public comment 
period is over and can we update the published version with WG updates. No 
response yet. 
07/07: No response. Alan will chase up 
14/07: No response from Joel. Sent email to Greg Newby by no response. 
21/07: Still no response. 
04/08: Joel has responded that it is up to the WG to decide if the changes 
are significant enough to need additional review. Alan to contact David 
Martin and Erwin Laure for guidance if we split the specification. 
11/08: Received a  response from Joel that the WG can decide if a re- 
public review is necessary before becoming a 'proposed recommendation'. 
Alan responded that the WG agreed that a re-review was not necessary. The 
next stage is for  OGF review committee to approve publication. 
11/08: Specification is now 'awaiting author changes' before being 
submitted to the OGF technical committee for approval as a 'proposed 
specification'. 
Alan would like to have the updated specification complete by Sept 10th. 
The WG needs to complete all actions by then or decide that they do not 
need to be included in this phase of the process. 
01/09: Alan and Steve have discussed and propose Sept 30th for completion 
of draft 43 and closure of all actions. 
08/09: Target for completion September 30. 
15/09: as above 
22/09: as above 
107
teston/testoff dfdl expression functions. 
Are these functions still needed. They were introduced to allow individual 
bits to be set in a byte. Steve to look at TLog and ISO 8583 formats that 
use existence flags to see if they are still required. 
04/08: Not discussed 
11/08: Not discussed 
25/08: Not discussed 
01/09: Steve to progress by Sept 30th 
08/09: Steve to progress by Sept 30th 
15/09: The ISO 8583 standard has existence flags at the beginning that are 
encoded so cannot be defined as an array of bits. Therefore DFDL needs the 
ability to set individual bits within an unsigned int. However the 
functions, particualry SetOn/Off,  as currently defined are not correct. 
SetOn returns a byte with the relevant bit set on. This must then be 
combined with other bytes which isn't very usable. Steve to circulate 
example of use and suggested improvements. 
22/09: Steve had documented the why the functions were required to parse 
ISO 8583 messages. He had suggested the following improvements 
xs:boolean dfdl:testBit(xs:unsignedByte, xs:unsignedByte)                 
       Returns Boolean true if the bit number given by arg #2 is set on in 
the byte given by arg #1, otherwise returns Boolean false. 
       
xs:unsignedByte dfdl:setBits(xs:boolean+)                                 
       Returns an byte being the value of the bit positions provided by 
the Boolean arguments, where true=1, false=0. The # of args must  8. 
 Note that  the bit numbering goes from left to right, in accordance with 
section 12.3.7.2 of the spec. 

The type was changed from unSignedLong to unSignedByte to avoid problems 
with padding when not enough bits are provided. 
111
Daffodil DFDL parser 
11/08: Bob and Alejandro described the new implementation that they have 
developed. It is a new code base and is not based on the Deffudle 
prototype. It is written in scala and implements approximately 80% of the 
features in the public comments draft of DFDL V1. Alejandro will send a 
list of the features not implemented. 
We discussed the scenarios that motivated the development which was to 
extract data from various sources and transform into canonical formats. 
Bob offered to make Daffodil available for the WG to assess the 
functionality. IBM WG members will get approval the company  to allow them 
to receive Daffodil. 
Bob raised the question that if Daffodil becomes the public implementation 
of DFDL then we will need to work out how that would be funded and 
managed. 
It would be helpful if IBM test cases were available to Daffodil. IBM will 
investigate 
25/08: Alejandro had sent a list of the functions that he has implemented 
and Steve ahd responding indicating the extra functions he thought were 
essential. 
Since then Alejandro has implemented some of the missing functions, such 
as escape schemes, pre-defined variables, binary decimal numbers, etc, and 
will update his list. 
Bob is planning to make the parser available on the internet to allow 
testing. 
His organisation is being reorganised and he doesn't know what the 
priority of  Daffodill will be so it is essential that we move quickly. It 
would help if IBM could indicate its support for Daffodil in some 
semi-formal way. 
01/09: Alejandro updating Daffodil to include escape schemes, unordered 
sequences and ignoreCase. 
Daffodil being placed under formal source control in anticipation of 
external release. 
Bob has a start October deadline to create a report on what has been done 
for his sponsors. 
It would be great if we could get Daffodil on the web and have run some 
IBM tests so it could be highlighted at OGF 30 at end October. 
08/09: Alejandro is marking up Spec draft 42 to indicate which features 
Daffodil implement. Bob expects Daffodil to be available on the web soon. 
15/09: Alejandro had indicated in the specification which functions were 
implemented in Daffodill. Steve had reviewed and identified which function 
need to be implemented and which could be considered optional (see action 
099). Alejandro is implementing the missing core functions. There was some 
discussion about the limitations on unordered groups. (stop value and 
expression not supported). It was agreed that it should be a schema 
definition error if dfdl:occursCountKind is 'stopValue' on any element 
within an unordered sequence and a floating element. 
22/09: not discussed 
112
DFDL certification process 
25/08: Discussed how to certify DFDL implementations. Alan to investigate 
if OGF have a defined process. 
01/09: In progress, spec needs to state what conformance means, as part of 
this work 
08/09: Discussed what needs to be said in the spec and agreed that details 
of a conformance test suite should be in another document. 
Alan to draft conformance section. 
15/09: Alan had look at the conformance sections in XML and Schema 
specifications both of which indicate sections which must be implemented. 
None just say 'execute the test suite'.  They talk in terms of conformance 
of document, schema and processors.. 
22/09: no progress 
114
OGF 30 
25/08: OGF30 takes place on October 25-29 in Brussels.  Should we have a 
WG session? 
09/01: Given emergence of NCSA implementation and spec completion target 
of 30th Sept it makes sense to host a session at OGF 30. 
08/09: Steve to request permission to go 
15/09: Travel request has be submitted 
118
2. Rules for 'missing' elements 

lengthKind='implicit' and xs:maxLength or xs:length is "0": element is 
missing 
lengthKind='implicit' and length is not "0": element is missing if it has 
an initiator AND emptyValueDelimiterPolicy excludes the initiator AND the 
initiator is not found in the data ( regardless of discriminators or 
initiatedContent ) 

lengthKind='explicit' and length is an expression : element is missing if 
the expression evaluates to zero. 
lengthKind='explicit' and length is "0": element is missing 
lengthKind='explicit' and length is not "0": element is missing if it has 
an initiator AND emptyValueDelimiterPolicy excludes the initiator AND the 
initiator is not found in the data ( regardless of discriminators or 
initiatedContent ) 

lengthKind='pattern' : element is missing if the length of the pattern 
match is zero 
lengthKind='prefixed' : element is missing if the prefixed length region 
parses as zero 

lengthKind='delimited' and delimiterPolicy='suppressed' and the end of the 
group has not been encountered : element is missing if it has an initiator 
AND emptyValueDelimiterPolicy excludes the initiator AND the initiator is 
not found in the data ( regardless of discriminators or initiatedContent ) 

lengthKind='delimited' and delimiterPolicy='suppressed' or 
'suppressedAtEnd'  and the end of the group has been encountered : element 
is missing 
lengthKind='delimited', all other cases : element is missing if its 
scanned length is zero 

lengthKind='endOfParent': element is missing if its scanned length is zero 


It is a schema definition error to specify emptyValueDelimiterPolicy 
'initiator' for lengthKind 'explicit' or 'implicit'. 

22/09: We discussed if these rules could be simplified to say an element 
is missing if it's initiator is missing or its content region is empty. 
Need further discussion. 
119
In passing we noted that the position of the prefix length relative to the 
initiator was not defined in the grammar and whether the prefix could have 
an initiator and terminator. Need further discussion

 
Regards

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