Hi Andy,
Looking good. One minor issue, the two argument form of session:get [1] with a default seems to be broken.
good catch; for some reason, the implementation of this function was set to private. I have just fixed this in the latest snapshot.
Also regarding the wiki session documentation: The session get/set functions are documented as only taking string values but, usefully, they will take other data such as nodes.
I couldn't reproduce this so far; do you have an example?
Christian