[DFDL-WG] DFDL: Action 071

[Steve Hanson]

Proposal as per last week's minutes:

We should be consistent with the similar property for missing separators. 
So I've changed the enums too - now 'require' and 'suppress', Also changed 
unparsing behaviour - we must honour the property - the existing behaviour 
of always writing the initiator means we can not successfully re-parse if 
writing empty content and enum is 'suppress'.  When reading, assume that 
section 15.13 has been updated to include complex as well as simple 
elements. 

missingValueInitiatorPolicy 
Enum 
Valid values ‘require', ‘suppress' 
Specifies whether to expect an initiator when an element is missing. 
Ignored unless dfdl:initiator is specified and is not "" (empty string). 
'require'  - Indicates that the dfdl:initiator followed by empty content 
is the required syntax to indicate that the element is missing.   
'suppress' - Indicates that empty content is the required syntax to 
indicate that the element is missing. The presence of an initiator implies 
that real content must follow. 
Use of ‘suppress’ implies an ordered sequence. If used on an initiated 
element of an unordered group it is a schema definition error. 
If the element is required, defaulting occurs as defined above. 
This property also applies on unparsing, when the data to be written 
(after nil value and default value processing) is empty content. 
Annotation: dfdl:element
We should similarly change the enums for nilValueInitiatorPolicy to 
'require' and 'suppress'. 
And we should back out work item 071 which suggests changing 
dfdl:separatorPolicy enumeration from 'require' to 'always'. That means 
'always' is matched with 'suppress' - but always is not a verb. 
Unparsing. Which branch of a choice do we output when a complex element is 
required but missing from the infoset? I think it should be the first 
branch of the choice that does not result in a processing error. 

Regards

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





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