[DFDL-WG] DFDL inputValueCalc restrictions

[Bradd Kadlecik]

The problem has more to do with "myIVC" not being required.  If a default
is not permitted then "myIVC" is required during unparse.


                                                                                   
 Regards,                                                                          
                                                                                   
 Bradd Kadlecik                                                                    
 z/TPF Development                                                                 
                                                                                   
                                                                                    
                                                                                    
                                                                                    
 Phone: 1-845-433-1573                                                2455 South Rd 
 E-mail: braddk at us.ibm.com                                         Poughkeepsie, NY 
                                                                         12601-5400 
                                                                      United States 
                                                                                    







From:	Mike Beckerle <mbeckerle.dfdl at gmail.com>
To:	Bradd Kadlecik <braddk at us.ibm.com>
Cc:	DFDL-WG <dfdl-wg at ogf.org>
Date:	10/16/2019 04:50 PM
Subject:	[EXTERNAL] Re: [DFDL-WG] DFDL inputValueCalc restrictions




So you are suggesting this:

        <element name="myOVC" type="xs:int"
dfdl:outputValueCalc="{ ../myIVC + 3 }" />
        <element name="myIVC" type="xs:int" dfdl:inputValueCalc="{ compute
here }" default="0"/><!-- default only used when unparsing -->

That's not unreasonable.

Question: Can the behavior you need be represented by way of a test for
existence of the IVC element?

<element name="myOVC" type="xs:int" dfdl:outputValueCalc="{ if (fn:not
(fn:exists(../myIVC))) then 0 else ....do the real computation
here.... }"/>
<!-- an optional IVC element -->
<choice>
    <sequence> <!-- IVC can't be root of a choice branch so workaround -->
        <element name="myIVC" dfdl:inputValueCalc="{ compute here }"/>
    </sequence>
    <sequence/> <!-- nothing at all is the other alternative -->
</choice>

That's clumsier, but does achieve, I think, the same behavior without
depending on defaulting. It does depend on fn:exists and fn:not functions.


Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology |
www.tresys.com
Please note: Contributions to the DFDL Workgroup's email discussions are
subject to the OGF Intellectual Property Policy



On Wed, Sep 25, 2019 at 11:49 AM Bradd Kadlecik <braddk at us.ibm.com> wrote:
  Hello,

  I have one item I'd like to discuss at some point regarding
  inputValueCalc and not allowing the default property to be specified. I
  have a use case where the default property would be useful for unparse.
  It makes perfect sense to not allow it for outputValueCalc however.

  The use case is in forming a connection between an inputValueCalc element
  and an outputValueCalc element where the incoming document might not
  contain the inputValueCalc element for unparse and a default value would
  be desired for the outputValueCalc use. This is an item our customers
  using DFDL would like to make use of but don't want to require the
  element to always exist for unparse.



                                                                                   
 Regards,                                                                          
                                                                                   
 Bradd Kadlecik                                                                    
 z/TPF Development                                                                 
                                                                                   


                                                                                    
                                                                                    
                                                                                    
 Phone: 1-845-433-1573                                                2455 South Rd 
 E-mail: braddk at us.ibm.com                                         Poughkeepsie, NY 
                                                                         12601-5400 
                                                                      United States 
                                                                                    




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