I know we discussed this extensively, and there are notes that the IBM DFDL implementation evaluates a dfdl:length expression when unparsing.

But searching the mail history, the trackers, etc. I cannot find a clear definitive statement of what we finally decided as to whether this is the official behavior or not.

I cannot find language in the DFDL spec that says that the dfdl:length expression is or is not evaluated.  (No such problem for dfdl:occursCountKind 'expression'. There we are very clear it is NOT evaluated when unparsing.)

There is this statement in the discussion of dfdl:contentLength function:

"When unparsing with dfdl:lengthKind "explicit", the calculation of dfdl:contentLength() returns the value of the dfdl:length property."

It does not say whether this forces the expression (if dfdl:length is an expression) to be evaluated or not, though it implies it must be evaluated because otherwise it would be undefined in that situation.

Is this the only situation during unparsing when the dfdl:length expression is evaluated?

...mike

Mike Beckerle | OGF DFDL Workgroup Co-Chair | Tresys Technology | www.tresys.com

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