I'm not sure where you got the idea that we are proposing a language where nothing ever changes :p Both Bloom and Edelweiss are ideas about how to model time/c

I'm not sure where you got the idea that we are proposing a language where nothing ever changes :p Both Bloom and Edelweiss are ideas about how to model time/change declaratively ie without having to specify control flow or incidental ordering. That doesn't seem to be too different to Glitch. Whether you think of imperative code pushing updates to data structures or declarative code pulling updates from stream is a matter of perspective. Either way, you still have to figure out how to order and combine those updates. Bloom takes the approach that each fact is true at an explicit point in time, so rather than mutating in place you simple define the state at time T+1 in terms of the state at time T. Both states are simultaneously accessible so you don't have to worry about what order the changes happen in. Edelweiss takes the approach discussed in Out Of The Tarpit where the true state is just the list of input events and everything else is an incrementally maintained view over these events. Edelweiss makes this practical by analysing datalog code to determine when an input event can no longer contribute to the state of the system. This is roughly analogous to GC, except that instead of relying on pointers to determine unreachability it uses static analysis. The appeal of this model is that you can always explain the state of system to the programmer by tracing backwards through the views.