Fri May 6 14:27:14 EDT 2011

Abstract code addresses

Can be abstracted in ATOM() constructors.  Need to change vm.c to
support these for: op_call/k_return and op_close/op_app.

I'm a bit puzzled why the nb arguments for app actually shows up at
the app side, and not at the code side.

Hmm, not so surprising really: it comes directly from the app syntax:
caller does not know arity of callee, so it's specified at the call
site.  Still, something isn't quite right in the way this is encoded.

Next: cleanup the nb_arg representation for op_app/op_close.

Q: why doesn't a closure for the k stack have a nargs field, while the
   op_app/op_close does?