elixir_interop.tp

;; Terp can use Elixir and Erlang functions.
;; To use them, prefix the fully qualified name
;; of the function (e.g. module.function) with a `:`
(provide square
         reverse-squares)

;; Set up types for the Elixir functions that are used.
;; Type inference cannot correctly infer their types out of the box.
;; To actually have useful type inference, must specify types
;; for Elixir/Erlang functions.
(type :Enum.reverse (-> [List a] [List a]))
(type :Stream.map (-> [List a] (-> (-> a b) [List b])))

;; Squares a list and reverses it.
(type reverse-squares (-> [List Int] [List Int]))
(defn reverse-squares (xs)
  (:Enum.reverse
   (:Stream.map xs (lambda (x) (* x x)))))