App stuff

[Ivan R. Judson]

> Regarding point number 2, I understand that join/leave is the 
> venue mechanism that gives applications the ability to 
> maintain general state (as in current slide number in a ppt 
> app, or vector list in a shared drawing program, etc) and a 
> general mechanism to pass it on to users that join an app in 
> progress, much like "enter" gives venue state to a client 
> entering a venue. This seems a very good and useful thing to 
> me, especially for the general class of shared app where 
> users need state when they join to get current with everyone else.

Right, I was definitely not talking about making all apps stateless. Just
perhaps defining the interaction more like the venue enter call, that
returns the current state then updates via the event channel.  There is
still a getstate call, but it's only used internally upon enter.

Similarly, when an app starts it has to contact the app object, in response
to initial contact it can get the state, then be connected to a coherence
event channel that provides incremental updates for the state.

Now, this doesn't address some of what Bob has discussed with respect to
knowing what users are currently using the shared app and what their state
is.  But I'm not sure I'm ready to bite that off yet -- I have to think
about it -- the value seems apparent but I want to chew on it a bit.

--Ivan