This is a reminder that we're having a DFDL Workgroup call this Thursday June 11, 11am EDT.US

Please send items you'd like on the agenda, and let me know if you plan to attend.

I have this topic for discussion:

* Peek feature - related Issue 66 - https://github.com/OpenGridForum/DFDL/issues/66 (about a lookAhead function)

An idea has been proposed to generalize this to a more flexible peek/look-ahead capability.

This is a requested feature for DFDL 2.0 allowing a parser to learn from examining the data once, and then use that knowledge in a subsequent parse over the same data.
Details:
- annotation on a xs:sequence 
- a parser to speculate forward and when it reaches the end of the sequence, resetting the position to the start of the sequence, but retaining information from the parse.
- the retained information certainly includes DFDL variables set during the peek-ahead parse.
- more controversial is the ability to retain the infoset, effectively allowing one to parse the same data multiple times. 
- does nothing on unparse. The annotated sequence is simply skipped by the unparser. 
- seems very easy to implement. 



Mike Beckerle 
Apache Daffodil PMC | daffodil.apache.org
OGF DFDL Workgroup Co-Chair | www.ogf.org/ogf/doku.php/standards/dfdl/dfdl
Owl Cyber Defense | www.owlcyberdefense.com