[DFDL-WG] DFDL inputValueCalc restrictions

Wed Sep 25 16:01:54 EDT 2019

Thanks for the link.  I agree with a number of items you have here as being
useful.  It seems like the best place to put something would be under
"Allowing some DFDL properties to Coexist with IVC".  The first paragraph
could end with: Also, the default property does not conflict and allows the
element to not be required during unparse.

I've also hit the problem of not having array variables and this seems
useful as well as parse-time forward reference.

 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:	09/25/2019 12:06 PM
Subject:	[EXTERNAL] Re: [DFDL-WG] DFDL inputValueCalc restrictions

Daffodil project has been building up an experience document about
inputValueCalc, outputValueCalc, and hidden groups. The draft is on our
wiki here:

https://s.apache.org/daffodil-experience-with-computed-elements

This will get finalized into an OGF Experience document and a number of
changes/corrections to the DFDL spec will come out of it I expect.

We already have identified that disallowing IVC and OVC on the same element
is unnecessary and sometimes you want this. Your case with default values
sounds similar.

We can incorporate your contribution to the experience document. Take a
look and see if the existing discussion can just be enhanced with a
sentence about also allowing default on an IVC element. If so I can edit
and add it there.

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 

  --
    dfdl-wg mailing list
    dfdl-wg at ogf.org
    https://www.ogf.org/mailman/listinfo/dfdl-wg

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.ogf.org/pipermail/dfdl-wg/attachments/20190925/320d0ccc/attachment.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: graycol.gif
Type: image/gif
Size: 105 bytes
Desc: not available
URL: <http://www.ogf.org/pipermail/dfdl-wg/attachments/20190925/320d0ccc/attachment.gif>