From tests IBM did, and experience with the DFDL schema for EDIFACT, I
This email summarizes trackers being created to track the resolution of Action 305. I have created trackers for all the topics below. This should enable us to close Action 305. *Tracker 351 on Separators and Separator Suppression* (I put a note on this tracker that this one still has email discussion ongoing about the precise wording.) I believe now we know that the suggestion below about Section 14.2 isn't correct. Pulling that discussion up to the top here, we suggested this: Section 14.2 For property dfdl:separator. The sentence: "Separators occur in the data either before, between or after all occurrences of the elements or groups that are the children of the sequence." replaced with "Separators occur in the data either before, between or after all occurrences of *represented* elements (that is, elements without the dfdl:inputValueCalc property) or model groups that are the children of the sequence. Elements with dfdl:inputValueCalc have no representation in the data stream, and so never have separators. Children of a sequence that are model groups are always separated, even if they are empty (meaning have no children of their own - which is allowed for sequence groups), or both the model group child and its contained children occupy zero-length in the data stream." think we neglected the potentially-trailing group case in the above description. I've revised it, with the new phrasing in blue. Section 14.2 For property dfdl:separator. The sentence: "Separators occur in the data either before, between or after all occurrences of the elements or groups that are the children of the sequence." replaced with "Separators occur in the data either before, between or after all occurrences of *represented* elements (that is, elements without the dfdl:inputValueCalc property) or model groups that are the children of the sequence. Elements with dfdl:inputValueCalc have no representation in the data stream, and so never have separators. Children of a sequence that are model groups are separated if the sequence is positional, even if they are empty (meaning have no children of their own - which is allowed for sequence groups), or both the model group child and its contained children occupy zero-length in the data stream. If the sequence is not positional, then separators are suppressed for trailing groups that are zero-length according to the dfdl:separatorSuppressionPolicy." This accommodates the common situation where a trailing sequence group contains an entirely optional array element. If none of the array elements exists we do not want a separator for the sequence group at all. (note: Some of the above is redundant with stipulations in the dfdl:inputValueCalc property description, but I believe it is wise to have this little redundancy.) *Tracker 350 on Empty Representation - Clarifications* Section 9.2.2 The phrase "the occurrence's content in the data..." replace with "the occurrence's SimpleContent or ComplexContent region in the data..." The sentence: "The *empty representation* is special in DFDL, because when parsing it is this condition that can trigger the creation of a default value for an element occurrence." replace with: "The empty representation is special in DFDL because when parsing it is used to determine when default values are created in the Infoset. The empty representation can require initiators or terminators be present so as to enable data formats to explicitly distinguish occurrences with empty string/hexBinary values from occurrences that are missing or are absent." (This is to clarify an error of omission - prior language suggested that EVDP is only relevant when the element has a default value, because only that need was mentioned.) *Tracker 233: Add to minor/typographical* Section 9.3.1.1 Delete phrase "...this of course implies that....". Note that there is already a correction to create numbered bullets of 3 sentences. The sentence containing this phrase will be bullet #3 of that list.
*Tracker 349: Clarifications on Element Defaults*
Section 9.4 Item 2 under "For elements and element refs:" Change to: "dfdl:element following property scoping rules, which includes establishing representation as described in Section 9.3.2 and conversion to element type for simple types." Section 9.4.2 Before the final phrase "There are three main cases to consider:" Insert this sentence: "The sections below indicate when an item is added to the infoset, and whether it has a default or other value. If there is no processing error then regardless of whether an item is added to the infoset or not, any side-effects due to dfdl:discriminator statements evaluating to true, or dfdl:setVariable statements, are retained." Sections 9.4.2.2 and 9.4.2.3 The phrase "Optional occurrence: If dfdl:emptyValueDelimiterPolicy is not 'none'*[12]* <http://daffodil.apache.org/docs/dfdl/#_ftn12>," Change to "Optional occurrence: if dfdl:emptyValueDelimiterPolicy is applicable and is not 'none',...." (retaining the footnote) Section 9.4.2.3. *(IGNORING THIS AS NO CONCLUSION WAS REACHED)* We agreed that the paragraphs beginning with "For both required and optional..." need to be better tied to the material above. Wording TBD - pending Steve Hanson doing some tests on IBM DFDL. I discovered that erratum 5.10 already includes modified wording equivalent to one of the things discussed: 5.10 says: Add a clause in 9.4.2.2 and 9.4.2.3 so that the statement about optional occurrences says "If dfdl:emptyValueDelimiterPolicy *is in effect and* is not 'none'...", as the words today do not cover cases when it is ignored (no initiator or terminator). Our discussion in this thread is slightly different wording: Sections 9.4.2.2 and 9.4.2.3 The phrase "Optional occurrence: If dfdl:emptyValueDelimiterPolicy is not 'none'*[12]* <http://daffodil.apache.org/docs/dfdl/#_ftn12>," Change to "Optional occurrence: if dfdl:emptyValueDelimiterPolicy is applicable and is not 'none',...." (retaining the footnote) I prefer the terminology "is applicable" here, as "in effect" can have the connotation of just "is set". *Tracker 348: Clarifications on Establishing Representation* Section 9.3.2 The phrase "The first step is to see if the content is trivaill of length zero." Change to: "The first step is to see if the SimpleContent or ComplexContnet region is of length zero as a first approximation." The bullet "delimited => length is zero (delimiter is immediately encountered)" Insert "in scope" after the open parenthesis. *Tracker 347: Clarifications on Specifying Delimiters*
Section 12.2
For property emptyValueDelimiterPolicy, before the phrase "It is a schema definition error if...", insert this sentence: "The value of dfdl:emptyValueDelimiterPolicy should only be checked if there is a dfdl:initiator or dfdl:terminator in scope. If so, and dfdl:emptyValueDelimiterPolicy is not set, it is a schema definition error. If dfdl:initiator is not "" and dfdl:terminator is "" and dfdl:emptyValueDelimiterPolicy is 'terminator' it is a schema definition error. If dfdl:terminator is not "" and dfdl:initiator is " and dfdl:emptyValueDelimiterPolicy is 'initiator' it is a schema definition error." *Tracker 346: Changes for Nillable Elements* Section 13.16 For property nilValueDelimiterPolicy, before the phrase "It is a schema definition error if...", insert this sentence: "The value of dfdl:nilValueDelimiterPolicy should only be checked if there is a dfdl:initiator or dfdl:terminator in scope. If so, and dfdl:nilValueDelimiterPolicy is not set, it is a schema definition error. If dfdl:initiator is not "" and dfdl:terminator is "" and dfdl:nilValueDelimiterPolicy is 'terminator' it is a schema definition error. If dfdl:terminator is not "" and dfdl:initiator is " and dfdl:nilValueDelimiterPolicy is 'initiator' it is a schema definition error ."