[DFDL-WG] Spec errata 3.3

[Mike Beckerle]

----- Message from Steve Hanson <smh at uk.ibm.com> on Tue, 21 Feb 2012
17:24:59 +0000 -----

To be discussed on next DFDL WG call.

As a result of action 136, the spec errata document currently says:

3.3. Section 12.3. Clarify that when property is lengthKind
'explicit', 'implicit', 'prefixed' or 'pattern', it means that
delimiter scanning is turned off and in-scope delimiters are not
looked for within or between elements.

Consequently remove the last paragraph of section 5.2.2 starting "It
is a processing error when a fixed-length string is found to have a
number of characters not equal to the fixed number".

It has been pointed out that for a complex element with lengthKind
'implicit', turning off in-scope delimiters is not a consistent
behaviour. Even though implicit means that the length is defined by
the child content, this is still subject to constraints imposed by the
parent. Further, as lengthKind 'implicit' is the implied lengthKind
for local sequences and choices, it should be possible to wrap such a
sequence or choice in an element with lengthKind 'implicit' and no
framing, and experience no behaviour change in parsing other than the
addition to the infoset of the element.  The ability to selectively
switch off in-scope delimiters is something that could be useful for
both 'implicit' and 'delimited' lengthKinds, and if so could be added
post 1.0 as a separate control.  The proposal is to change errata 3.3
to read:

3.3. Section 12.3. Clarify that when property lengthKind is
'explicit', 'prefixed' or 'pattern', then delimiter scanning is turned
off and in-scope delimiters are not looked for within or between
elements.

Clarify that when property lengthKind is 'implicit' and type is
simple, then delimiter scanning is turned off and in-scope delimiters
are not looked for within or between elements.

Clarify that when property lengthKind is 'implicit' and type is
complex, then delimiter scanning is not turned off and in-scope
delimiters are looked for.

Consequently remove the last paragraph of section 5.2.2 starting "It
is a processing error when a fixed-length string is found to have a
number of characters not equal to the fixed number".

Regards

Steve Hanson
Architect, Data Format Description Language (DFDL)
Co-Chair, OGF DFDL Working Group
IBM SWG, Hursley, UK
smh at uk.ibm.com
tel:+44-1962-815848

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