[DFDL-WG] DFDL: Calculated Values section rewrite

[Alan Powell]

Mike

A couple of comments on the using derived/representation nomenclature with 
OutputValueCalc and a couple of minor corrections.

However I thought the Length Prefix example a bit odd as I would have 
expected a single HexBinary element rather than an array of bytes. 

And that got me thinking why isn't it just LengthKind=prefixed but I 
discovered that there is no proper description of prefixed. Was it 
intended to cover different kinds of length prefix or is it assumed to be 
2 (or 4) bytes?





Alan Powell

 MP 211, IBM UK Labs, Hursley,  Winchester, SO21 2JN, England
 Notes Id: Alan Powell/UK/IBM     email: alan_powell at uk.ibm.com 
 Tel: +44 (0)1962 815073                  Fax: +44 (0)1962 816898




From:
"Mike Beckerle" <mbeckerle.dfdl at gmail.com>
To:
<dfdl-wg at ogf.org>
Date:
26/03/2008 16:39
Subject:
[DFDL-WG] DFDL: Calculated Values section rewrite



My deliverable for the next draft (32) was to revise the calculated values 
section.
 
I have rewritten it and the draft is attached. 
 
Of note: I have removed the troublesome ?outputLengthCalc? property, as I 
no longer see a critical need for it. One of the examples computes the 
number of occurrences for a byte array, and I think that mechanism along 
with alignment is sufficient to handle the troublesome cases I was 
considering where size of padding had to be dynamically computed.
 
The section now consists of a short table of definition, followed by 
illustrative examples, however, I think this is fine. The semantics of 
inputValueCalc and outputValueCalc aren?t really that complex. They can be 
described in a paragraph. It is the motivation for them that is 
complicated, so I think examples in the spec, while sometimes considered 
problematic, are OK in this case.
 
 
 
 [attachment "calculated-value-properties.doc" deleted by Alan 
Powell/UK/IBM] --
  dfdl-wg mailing list
  dfdl-wg at ogf.org
  http://www.ogf.org/mailman/listinfo/dfdl-wg






Unless stated otherwise above:
IBM United Kingdom Limited - Registered in England and Wales with number 
741598. 
Registered office: PO Box 41, North Harbour, Portsmouth, Hampshire PO6 3AU





-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://www.ogf.org/pipermail/dfdl-wg/attachments/20080327/08bc7d56/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: calculated-value-properties AWP.doc
Type: application/octet-stream
Size: 143360 bytes
Desc: not available
Url : http://www.ogf.org/pipermail/dfdl-wg/attachments/20080327/08bc7d56/attachment-0001.obj