Seeing how closely TopShell resembles Haskell I am curious why you chose to implement it in Scala rather than Haskell or Purescript.
While I've written a compiler in Haskell in the past, and prefer the language in many ways, I don't know how to do front end programming in Haskell, compile Haskell to efficient JS or debug performance problems. I also don't know if there's a good Haskell IDE these days. PureScript would have been risky for me, since I haven't done anything in it before.