(deftag compile [body] (quasiquote (eval-when-compile ~body)))

#compile
(import [hy.models [HyList HyDict HySymbol HyKeyword]])

#compile
(defn annotation-symbol? [form]
  (and (instance? HyKeyword form) (= (name form) ":")))

#compile
(defn ldrop [count coll] (list (drop count coll)))

#compile
(defn get-annotations [args annotations valid-args]
  (if
    (empty? args) None

    (= (len args) 1) (.append valid-args (get args 0))

    (annotation-symbol? (get args 1))
      (do
        (.append annotations (mangle (get args 0)))
        (.append annotations (get args 2))
        (.append valid-args (get args 0))
        (get-annotations (ldrop 3 args) annotations valid-args))

    (do
      (.append valid-args (get args 0))
      (get-annotations (ldrop 1 args) annotations valid-args))))

(defmacro defna [name args expression]
  (do
     (setv annotations [])
     (setv valid-args  [])
     (get-annotations args annotations valid-args)
     (quasiquote
      (do
        (defn ~name ~(HyList valid-args) ~expression)
        (assoc (. ~name __annotations__) ~@annotations)))))

;; Example

(defna add+ [a :: int b :: int c] (+ a c))