James,
The error message is because you don't make forward progress through the
data with potentially unbounded occurrences. Is this because you are using
a cut-down schema? If there are delimiters then model those and you might
not get the error.
Once you have processed the array you can use asserts to check the count.
However IBM DFDL does not implement the count functions yet.
Give me a couple of days to look at this more closely. I have a customer
visit tomorrow hence the delay.
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
From: "Garriss Jr., James P."
To: "dfdl-wg@ogf.org" ,
Date: 05/03/2013 16:19
Subject: Re: [DFDL-WG] unordered sequence with constrained
occurrences
Sent by: dfdl-wg-bounces@ogf.org
Hmmm, maybe not. I said:
The unordered sequence can be modeled with a data array
Yet when implemented in MBTK, it throws a fatal error:
fatal: CTDP3148E: Infinite loop at offset 3: The DFDL parser cannot
process array element 'ABCarray' because maxOccurs is unbounded and the
length of the previous occurrence was zero.
I think what happens is that on the last pass through the array, it
doesn’t find a, b, or c, so it throws a fatal error.
So is this a bug in MBTK? Or can DFDL not model an unordered sequence? Or
am I just doing it wrong?
Here’s a sample DFDL schemas that illustrates the point:
<?xml version="1.0" encoding="UTF-8"?>
http://www.ogf.org/dfdl/dfdl-1.0/"
xmlns:fmt="http://www.ibm.com/dfdl/GeneralPurposeFormat"
xmlns:ibmSchExtn="http://www.ibm.com/schema/extensions" xmlns:xsd="
http://www.w3.org/2001/XMLSchema">
http://www.ibm.com/dfdl/GeneralPurposeFormat"
schemaLocation="IBMdefined/GeneralPurposeFormat.xsd" />
xsd:complexType
xsd:annotation
http://www.ogf.org/dfdl/">
xsd:complexType
xsd:annotation
http://www.ogf.org/dfdl/">
Test with “abc” as sample input.
From: Garriss Jr., James P.
Sent: Tuesday, March 05, 2013 8:43 AM
To: dfdl-wg@ogf.org
Subject: unordered sequence with constrained occurrences
Suppose text data has 3 constructs: a, b, and c.
· a must occur 1 time
· b can occur 0 or 1 time
· c can occur any number of times, 0 or more
These 3 constructs can appear in any order.
So these are valid inputs:
abc
a
bcccca
But these are not:
ccbcc
abbc
abcabc
Can data like this be modeled with DFDL?
The unordered sequence can be modeled with a data array, like this:
Array (0 to unbounded)
Sequence
a (0 to 1)
b (0 to 1)
c (0 to 1)
/Sequence
/Array
But I don’t know how to constrain the total number of occurrences.
Appreciate any ideas!--
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