[DFDL-WG] clarification needed on lengthKind='pattern' inside complexType element with lengthKind='delimited'

[Steve Hanson]

Mike

The latest internal draft of the spec says:

"When dfdl:lengthKind is 'pattern', it means that delimiter scanning is 
turned off and in-scope delimiters are not looked for within or between 
elements."

This is from errata 3.3:

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

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



From:   Mike Beckerle <mbeckerle.dfdl at gmail.com>
To:     dfdl-wg at ogf.org, 
Date:   24/10/2012 20:16
Subject:        [DFDL-WG] clarification needed on lengthKind='pattern' 
inside complexType element with lengthKind='delimited'
Sent by:        dfdl-wg-bounces at ogf.org




If I nest an element having lengthKind='pattern' inside a complexType 
element with lengthKind='delimited' I wanted to clarify the behavior of 
the pattern matching.

I've been assuming the pattern does NOT get stopped by occurrances of the 
delimiters. That is, the pattern scan is in no way adapted to being inside 
of a delimited context.

The alternative would be that the lengthKind="pattern" element's pattern 
would be augmented by something allowing it to stop if the delimiter were 
encountered, possibly taking even escape schemes into account, etc.

This does not seem worth it to me. It seems like the behavior for 
lengthKind='pattern' should be greedy, and blind to enclosing delimiters. 
Precedent is that lengthKind="explcit" is also blind to enclosing 
delimiters.

Comments?

-- 
Mike Beckerle | OGF DFDL WG Co-Chair 
Tel:  781-330-0412
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