[boothead]

I've built some real time front end stuff with knockout (due to starting off with backbone and still wanting to use the models and collections via knockback) so I'm not a complete beginner. I'm struggling with which reactive UI library to go with, but I think I'm basically down to ember and angular. Here's how I want to build my next app:

Haskell on the backend. Probably with data in postgres, but using an event sourcing kind of pattern for the bits of state which are edited.

Communication between the browser, other systems and the back end should allow separation of query and command (so updates are pushed to the backend state via one channel and pubslished back out via another). However it should be essentially realtime - websockets.

Operational transform for edits to the state. I'm on the fence with this one as I'm not sure what the overlap is between event sourcing and OT. Anyone who's implemented either care to comment? This seems to equate to using sharejs on the front end to marshal changes in the model to the back end and vice versa?

I'd consider using one of the haskell -> js libraries, but I'd also go with coffeescript here happily. I've played with Fay a bit and sunroof looks good too. Anyone using these?

The stuff above has been percolating for a while based on my experiences building the infrastructure for a hedge fund recently, and the gradual evolution from a mostly traditional restful app to a much more realtime system. Does anyone have any thoughts (not necessarily just on the specific technology mentioned but on how it all might fit together)?