For discussion on today's call
Regards
Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
----- Forwarded by Steve
Hanson/UK/IBM on 16/10/2012 13:13 -----
From:
Mike Beckerle <mbeckerle.dfdl@gmail.com>
To:
Steve Hanson/UK/IBM@IBMGB
Date:
02/10/2012 18:41
Subject:
One email or
a flock or... - re: 10.03 draft - open review items
Steve,
I've got the issues below left after your review pass on 10.03, minus 2
I send emails to you about separately.
Should I issue this email to the WG, or do you want me to decompose this
into separate emails, or do you just want to list these as agenda topics
for next call? I think it is good if people get to look at them in advance
of a call.
...mikeb
--------------------------------------------------------
This is a list of items left open after a review pass by SMH(on draft in
preparation r010.03).
These items need specific WG discussion on a call. They may be small enough
to resolve there, or may be escalated into action items. (A couple issues
already clearly action-item related are not listed here.)
Note: please Ignore the identifiers like SMH107 or m236 I'm tagging these
with. Those are just for me editing the text. (Those change ...grrr...
if someone inserts a comment into the document, so they're not good issue
identifiers).
1. SMH107
Spec says: When the separator and terminator on a group have the
same value, then at a point where either separator or terminator could
be found, the separator is tried first.
- Issue is that this language still feels ambiguous. E.g.,
So it tries the separator first, let’s say it finds it. Will a subsequent
processing error cause it to backtrack and revisit this and try the terminator?
Or does finding the separator confirm that it IS a separator, resolve forever
that point of uncertainty? I believe the latter is what was intended (delimiter
decisions drive parsing and are not revisited), but we need to state this
(or do we somewhere else already?)
2.
SMH169 - Some numeric
types are signed, others unsigned. Some representations are sign-capable,
some are not (BCD specifically). Right now spec draft says you can't have
bcd as rep for signed integer types long, int, short, byte. But you CAN
have bcd for rep of decimal, integer. We could allow bcd only for nonNegativeInteger
type, but there is no nonNegativeDecimal type, so....how to resolve? I
would suggest that we simply allow bcd as rep for both signed and unsigned
types, and it's a processing error to unparse a negative value into bcd
rep.
3. m229
- textStandardZeroRep - should this allow %ES; as one of the list of possibles?
4. m236
- is V (virtual decimal point position) and also P allowed in the textNumberPattern
for double and float types?
5. m237
- Do we check that the various symbols used for infinity, digits, grouping
separators, decimal separators are properly distinct to allow parsing?
E.g., that the decimal separator and grouping separator aren't the same,
and that the positive and negative pattern variants are distinguishable?
ICU library supposedly doesn't do this checking. Do we state this is an
SDE in DFDL. If so then is this checking required? Can we make it possible
for implementations to not check somehow? Other grammar ambiguity situations
like separator and terminator being ambiguous are specifically NOT checked
for, because determining if a grammar is ambiguous is hard or undecidable,
and would have to be done at runtime because delimiters can be run-time
computed. Buf for the syntax components of text numbers do we require checking
or not?
6. m370
- multiple PoU resolutions: If you have initiatedContent, AND a choiceBranchRef,
AND a discriminator all on the same element, and there are 3 enclosing
nested PoU, which one controls which? Precedence is the issue. Or.....
do we really need to allow this? Why don’t we just disallow this kind
of piling-on of complexity and make the user choose which PoU resolution
technique they want?
7. m396
- is BCD representation a mandatory feature, or optional?
8. m398
- portability at risk if subset processors ignore properties they don't
implement. We relaxed this from a more rigid policy, and now allow subsets
to not validate properties they don't implement. However, is there a better
compromise, e.g., require a warning about all unimplemented/unrecognized
properties? E.g., dfdl:textBiDi='no' yields SDE "unrecognized property
'textBiDi' with value 'no'.
--
Mike Beckerle | OGF DFDL WG Co-Chair
Tel: 781-330-0412
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