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@uk.ibm.com
Tel: +44 (0)1962 815073
Fax: +44 (0)1962 816898
| From:
| "Mike Beckerle" <mbeckerle.dfdl@gmail.com>
|
| To:
| <dfdl-wg@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] --
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