[DFDL-WG] Consolidated Notes including both DFDL WG Call 2018-08-07 along with other recent clarification email threads

Tue Aug 7 13:29:20 EDT 2018

This message includes two parts.

Part 1 is the things we discussed on the DFDL WG Call of 2018-08-07.
Part 2 is the other recent emails where the conclusion from the email
thread is repeated here for finalization/refinement, and for consolidation
so all these changes can be considered together.

================================

Part 1 - Discussed on the call.  Re: [DFDL-WG] Clarification discussion
points for next call(s) - DFDL Spec issues around nil, empty, normal,
absent, defaulting, and separator suppression.
Dated August 2nd

Conclusions:

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.

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 9.3.2
  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.

Section 9.4.2.3.
  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.

============================

Part 2 - Below are conclusions from the prior email threads. This is for
email review in lieu of discussion on this week's call.
Re: [DFDL-WG] clarification: on suppressed ZL string/hexBinary - do we keep
variable assignments?Of Aug 6 (last date in the thread)

These corrections apply:

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
   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."

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."

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
."

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 it is used to
determine when default values are created in the Infoset, and when optional
recurring elements are omitted from the Infoset. The empty representation
can require initiators or terminators be present so as to enable data
formats to explicitly distinguish empty-string/hexBinary values (which
might cause default values to be used) from emptiness meaning the absence
of any representation."
     (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.)

Re: [DFDL-WG] Clarification needed: separator for empty sequence
Of Aug 2

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."
   (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.)

======================

These email threads are mentioned here to indicate that they are resolved
by one or another of the above corrections:

Re: [DFDL-WG] clarification needed - ambiguity about empty string and
optional element
Of Aug 2
Re: [DFDL-WG] Spec correction ? - Section 9.3.2.1 - second list missing
"empty" representationOf Aug 2

-----------

Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
Please note: Contributions to the DFDL Workgroup's email discussions are
subject to the OGF Intellectual Property Policy
<http://www.ogf.org/About/abt_policies.php>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ogf.org/pipermail/dfdl-wg/attachments/20180807/2668de44/attachment-0001.html>