Are list comprehensions still part of ES7? It's strange that Babel removed the list comprehension transformer recently, but I haven't been following closely.

The Elixir pipe syntax is reminiscent of Clojure's ->/->>:

  (->> (range 1 10)
       (map #(* % %))
       (filter (partial > 40)))

It's nice that in languages like Haskell or ML this is trivial:

  infix |> 
  fun (a |> b) = a b

You could modify this to let NONE fall through, etc.