[DFDL-WG] Can I concatenate a variable?

[Tim Kimber]

Hi James,

In section 12.3.5 of the specification, the 'lengthPattern' property is 
listed as having the type 'DFDL Regular expression'. Unlike some other 
properties, dfdl:lengthPattern cannot be a DFDL expression. Therefore it 
cannot contain a DFDL variable reference.

On the other hand, section 14.2 lists the data type of dfdl:separator as '
List of DFDL String Literals or DFDL Expression', However, your 
dfdl:separator is not a valid DFDL expression. The property must be either 
a valid DFDL expression or a list of DFDL string literals. The syntax you 
need is 

<xsd:sequence dfdl:separator="{fn:concat('--'),$some_boundary}" 
dfdl:separatorSuppressionPolicy="anyEmpty"  dfdl:terminator="--%CR;%LF;">

regards,

Tim Kimber, DFDL Team,
Hursley, UK
Internet:  kimbert at uk.ibm.com
Tel. 01962-816742 
Internal tel. 37246742




From:   "Garriss Jr., James P." <jgarriss at mitre.org>
To:     "dfdl-wg at ogf.org" <dfdl-wg at ogf.org>, 
Date:   24/06/2013 20:38
Subject:        [DFDL-WG] Can I concatenate a variable?
Sent by:        dfdl-wg-bounces at ogf.org



Suppose I define a variable like this:
 
<dfdl:defineVariable name="boundary" defaultValue="some_boundary" type=
"xsd:string"/>
 
Can I later concatenate it with other values? 
 
For example, can I concatenate it as part of a pattern?
 
<xsd:element name="Preamble" type="xsd:string" dfdl:lengthKind="pattern" 
dfdl:lengthPattern="(.+?)(?=--{$some_boundary})"/>
 
Can I concatenate it as part of a separator?
 
<xsd:sequence dfdl:separator="--{$some_boundary}" 
dfdl:separatorSuppressionPolicy="anyEmpty"  dfdl:terminator="--%CR;%LF;">
 
TIA!--
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