[DFDL-WG] V3 of length/occurs simplification proposal

[Simon Parker]

Hmmm...
 
I wasn't around for 'occursStopValueKind', so excuse me if I miss the
point.
 
Here's a question and a tentative answer I was playing with recently:
 

	What's the difference between stopValue and terminator?
	'terminator' can be used to scan a stream of characters or bits
without parsing elements
	'stopValue' can be used to scan a sequence of parsed elements.
Its datatype must be the same as the array element.

If I'm right, then Steve's example is invalid because "done" is not an
integer. To make it valid, either:
    - the stopValue must be an 'int' such as -1, or
    - the out-of-band value "done" or "|done" must be a terminator for
an enclosing construct as follows.
 
Change this:
<element name="x" type="int" maxOccurs="unbounded"
dfdl:occursSeparator="|" dfdl:occursKind="stopValue"
dfdl:stopValue="done" dfdl:occursStopValueKind="literal"
dfdl:representation="text"/> 
to this:
<sequence dfdl:lengthKind="delimited" dfdl:terminator="|done"
dfdl:applies="hereonly">
    <element name="x" type="int" maxOccurs="unbounded"
dfdl:occursSeparator="|" dfdl:occursKind="endOfData"
dfdl:representation="text"/> 
</sequence>
 
If I'm wrong, then what is the correct answer to the question?
 
---
 
If we change the name of the property 'stopValue', then I would find
these candidates consistent with similar concepts elsewhere:
    occursTerminator
    occursTerminatorValue
    terminatorValue
 
 Simon
 



________________________________

	From: dfdl-wg-bounces at ogf.org [mailto:dfdl-wg-bounces at ogf.org]
On Behalf Of Mike Beckerle
	Sent: 29 August 2007 19:52
	To: Steve Hanson
	Cc: dfdl-wg at ogf.org; dfdl-wg-bounces at ogf.org
	Subject: Re: [DFDL-WG] V3 of length/occurs simplification
proposal
	
	
	
	Seems like occursStopValueKind="literal" only applies to
representation="text". 
	
	With that caveat, I think I agree we need to be able to say 
	
	<element name="x" type="int" maxOccurs="unbounded"
dfdl:occursSeparator="|" dfdl:occursKind="stopValue"
dfdl:stopValue="done" dfdl:occursStopValueKind="literal"
dfdl:representation="text"/> 
	
	Then this would be valid 3 occurences for element x. 
	
	2|3|4|done 
	
	I think we shoudl rename dfdl:stopValue to dfdl:occursStopValue
for consistency. 
	
	
	Mike Beckerle
	STSM, Architect, Scalable Computing
	IBM Software Group
	Information Platform and Solutions
	Westborough, MA 01581
	direct: voice and FAX 508-599-7148
	assistant: Pam Riordan   
	                 priordan at us.ibm.com 
	                 508-599-7046
	
	
	
	
	
Steve Hanson <smh at uk.ibm.com> 

08/29/2007 01:32 PM 

To
Mike Beckerle/Worcester/IBM at IBMUS 
cc
dfdl-wg at ogf.org, dfdl-wg-bounces at ogf.org 
Subject
Re: [DFDL-WG] V3 of length/occurs simplification proposal

	




	
	Mike - looking at an old level of the spec, we had a
occursStopValueKind property, with enums 'logical', 'literal' and
'missing'.  Analogous to nullvalueKInd property.  I'm sure we want to
handle 'missing' differently but the literal v logical distinction is
required. How are we proposing to cover this? 
	
	Regards, Steve
	
	Steve Hanson
	WebSphere Message Brokers
	Hursley, UK
	Internet: smh at uk.ibm.com
	Phone (+44)/(0) 1962-815848 
	
	
Mike Beckerle <beckerle at us.ibm.com> 
Sent by: dfdl-wg-bounces at ogf.org 

29/08/2007 16:29 



To
dfdl-wg at ogf.org 
cc
Subject
[DFDL-WG] V3 of length/occurs simplification proposal


	


	
	
	
	Based on minutes from last week's meeting I've updated to v3 the
proposal for simplifying length/occurs properties. 

	Changes are marked with comments. --
	dfdl-wg mailing list
	dfdl-wg at ogf.org
	http://www.ogf.org/mailman/listinfo/dfdl-wg 
	
	
	
	
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