we've got session transactions! have a look at examples/transaction.lisp in a upto the minute ucw (ucw--dev--0.1--patch-94). nested transaction need a bit more thought but basically the idea is this: you setup up a start and end session-frame, when you get past the end frame every action beteen the start and end is substituted with an action which just takes you to the final component.
the request-response loop has been completly refactored, i've elimintated a bunch of special variables in favor of a single *context* special which is a request-contex object holding all the various "stuff" we need during a request-response iteration. in the process ucw has lost a lot of error handling code, a bunch of things which previously gave you a heplful page explaining what went wrong now just drop you into the debugger.
anyway, if anybody wants to go stomp on ucw a bit i'd be happy to know where it breaks. (i've tested only on openmcl + aserve.)
-- Marco Ring the bells that still can ring. Forget the perfect offering. There is a crack in everything. That's how the light gets in. -Leonard Cohen