Unchecked Math

compile-time-unchecked-math.clj

(ns PathFollowerUnity
  (:import 
    (UnityEngine Transform Debug GUILayout)
    (PathFollowerUnity PathFollower)))

(defmacro with-unchecked-math [& xs]
  `(binding [*unchecked-math* true]
     ~@xs))

(defmacro get-component* [obj t]
  (with-meta `(.GetComponent ~obj (~'type-args ~t))
    {:tag t}))

(with-unchecked-math
  (gen-class
    :name PathFollowerUnity.PathFollower
    :methods [[Update [] void]]
    :main false
    :extends UnityEngine.MonoBehaviour
    :prefix "PathFollower-"
    :init init
    :state state)

  (defn PathFollower-init []
    [ []
      (into-array System.Object
        (vec (repeatedly 1000 #(Vector3. (rand-int 30) (rand-int 18) 0))))])

  (defn PathFollower-Update [^UnityEngine.Component self]
    (let [^objects ary (.state self)
          current-pos (aget ary Time/time)
          next-pos (aget ary (inc Time/time))
          transform (get-component* self Transform)]
      (set! (.localPosition transform)
        (Vector3/Lerp
          current-pos
          next-pos
          (rem Time/time 1))))))

CompileTimeUnckeckedMath.il.cs

public override object invoke (object obj)
{
  // runtime call to binding gone, try/finally gone
	object obj2 = PathFollowerUnity$fn__28$PathFollower_Update__47__51.__interop_state53 (obj);
	object obj3 = ((object[])obj2) [RT.intCast (Time.time)];
	object obj4 = ((object[])obj2) [RT.intCast ((double)Time.time + (double))];
	object component = ((Component)obj).GetComponent<Transform> (); // same
	object result;
	// same
	((Transform)component).localPosition = (Vector3)(result = Vector3.Lerp ((Vector3)obj3, (Vector3)obj4, (float)Numbers.remainder ((double)Time.time, )));
	return result;
}

Original.il.cs

public override object invoke (object obj)
{
  // run time cost associated with the binding form
  ((IFn)PathFollowerUnity$PathFollower_Update__569.const__0.getRawRoot ()).invoke (((IFn)PathFollowerUnity$PathFollower_Update__569.const__1.getRawRoot ()).invoke (PathFollowerUnity$PathFollower_Update__569.const__2, ));
  object result;
  try { //  why does clojure emit a try/finally?
    object obj2 = PathFollowerUnity$PathFollower_Update__569.__interop_state571 (obj);
    object obj3 = ((object[])obj2) [RT.intCast (Time.time)];
    object obj4 = ((object[])obj2) [RT.intCast ((double)Time.time + (double))];
    object component = ((Component)obj).GetComponent<Transform> (); // perfect
    object obj5;
    // perfect (next line)
    ((Transform)component).localPosition = (Vector3)(obj5 = Vector3.Lerp ((Vector3)obj3, (Vector3)obj4, (float)Numbers.remainder ((double)Time.time, )));
    result = obj5;
  }
  finally {
    // not sure what this is, could be 'undoing' the binding?
    ((IFn)PathFollowerUnity$PathFollower_Update__569.const__8.getRawRoot ()).invoke ();
  }
  return result;
}