Mike
I think that we can add clauses to sections
16.1.1 through 16.1.5 (where needed). We don't need a new section. And
we don't need any additions to section 14.2.2 or 14.2.3 - the wording implies
that separators only appear when an occurrence is output. http://redmine.ogf.org/issues/244
Regards
Steve Hanson
Architect, IBM
DFDL
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
From:
Mike Beckerle <mbeckerle.dfdl@gmail.com>
To:
Steve Hanson/UK/IBM@IBMGB
Cc:
DFDL-WG <dfdl-wg@ogf.org>
Date:
25/11/2014 15:53
Subject:
Re: [DFDL-WG]
Action 271: semantic of maxoccurs '0'
I think we need to add Section 16.1.6, which is titled
"When maxOccurs is Zero". (The other possible place is 16.9,
but I think that is very far from where the information is needed.) This
is where the table goes specifying the maxOccurs 0 behavior.
A forward reference to this section should be added in
section 14.2.2 in the paragraphs about 'fixed', 'implicit', and 'expression'.
A forward reference to this section should also be added
in section 16.1.1, 16.1.2, and 16.1.4, which are the sections about fixed,
implicit, and expression.
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
On Tue, Nov 18, 2014 at 6:39 AM, Steve Hanson <smh@uk.ibm.com>
wrote:
We still need words to capture what
is in the two tables though. The spec today does not say what the
parser or unparser does when asked to process zero occurrences of an element
(whether stipulated by maxOccurs or dfdl:occursCount), and that's the behaviour
given in the tables and accompanying notes.
Regards
Steve Hanson
Architect, IBM
DFDL
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
From: Mike
Beckerle <mbeckerle.dfdl@gmail.com>
To: Steve
Hanson/UK/IBM@IBMGB
Cc: DFDL-WG
<dfdl-wg@ogf.org>
Date: 17/11/2014
20:02
Subject: Re:
[DFDL-WG] Action 271: semantic of maxoccurs '0'
I looked through the Spec at each use of the word maxOccurs.
I saw nowhere that had to be modified if we stipulate that maxOccurs can
be zero.
Hence, I think the only thing we need to do is (1) explicitly state maxOccurs
can be zero, and I suggest we also provide a suggested use case. I think
the use case would be to accept a prior version of a DFDL-described data
format, but have validation fail for elements that are not supposed to
be present anymore in a revised version of that schema.
I believe section 5.2.1 is the right place for this stipulation. The use
case can go in a footnote perhaps.
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
On Mon, Oct 13, 2014 at 10:39 AM, Steve Hanson <smh@uk.ibm.com>
wrote:
|
271
| Use
of maxOccurs '0' (All)
2/9: Legal in XSDL and DFDL. One use case in XSDL is when deriving a complex
type by restriction, where it is used to indicate that an element in the
base type must not appear. Another use case could be if a schema undergoes
a version revision that removes elements; perhaps clearer if the removed
element gets maxOccurs '0' rather than omitting it. Steve has seen an instance
of its use in a DFDL schema.
So if DFDL continues to support it, need to document the behaviour for
the various occursCountKinds and what happens to separator. Also behaviour
of occursCount expression that returns 0. Proposal needed.
...
23/9: No progress |
IBM has discussed this internally and
has the following proposal. Infoset refers to the augmented infoset.
| OCK
|
maxOccurs '0'
|
| Parsing
| Unparsing
|
| fixed
| No
occurrences looked for in the data (1)
| No
occurrences looked for in the infoset or written (2)
|
| implicit
| No
occurrences looked for in the data (1)
| No
occurrences looked for in the infoset or written (2)
|
| expression
| occursCount
occurrences expected. If any are found it is a validation error.
| Any
number of occurrences expected in the infoset and written. If any are found
it is a validation error.
|
| parsed
| Any
number of occurrences expected in the data. If any are found it is a validation
error.
| Any
number of occurrences expected in the infoset and written. If any are found
it is a validation error.
|
| stopValue
| Any
number of occurrences expected in the data. If any are found it is a validation
error.
| Any
number of occurrences expected in the infoset and written. If any are found
it is a validation error. |
| OCK
| Parsing
and occursCount '0'
| Unparsing
and no occurrences in infoset
|
| expression
| No
occurrences looked for in the data. (1)
| No
occurrences written. (2) |
Notes
(1) If sequence has a separator, no separator
is looked for in the data when parsing.
(2) If sequence has a separator, no separator
is output when unparsing.
Regards
Steve Hanson
Architect, IBM
DFDL
Co-Chair, OGF
DFDL Working Group
IBM SWG, Hursley, UK
smh@uk.ibm.com
tel:+44-1962-815848
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IBM United Kingdom Limited - Registered in England and Wales with number
741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU
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Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number
741598.
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6
3AU