derive EnemyPhysics module from functor

fcore/constants.sml

@@ -28,4 +28,5 @@ struct
   (* constants for enemy *)
   val enemySize = 35
   val enemySizeReal: Real32.real = 35.0
+  val moveEnemyBy = 5
 end

fcore/enemy-patch.sml

@@ -1,4 +1,18 @@
-structure EnemyPatch =
+signature ENEMY_PATCH =
+sig
+  datatype enemy_patch =
+    W_HEALTH of int
+  | W_X of int
+  | W_Y of int
+  | W_X_AXIS of GameType.x_axis
+  | W_Y_AXIS of GameType.y_axis
+
+  val withPatch: GameType.enemy * enemy_patch -> GameType.enemy
+
+  val withPatches: GameType.enemy * enemy_patch list -> GameType.enemy
+end
+
+structure EnemyPatch: ENEMY_PATCH =
 struct
   datatype enemy_patch =
     W_HEALTH of int

fcore/physics.sml

@@ -94,3 +94,26 @@ structure PlayerPhysics =
        val W_Y = PlayerPatch.W_Y
        val W_Y_AXIS = PlayerPatch.W_Y_AXIS
      end)
+
+structure EnemyPhysics =
+  MakePhysics
+    (struct
+       type t = GameType.enemy
+       type patch = EnemyPatch.enemy_patch
+
+       (* constants for physics *)
+       val moveBy = Constants.moveEnemyBy
+       val floatLimit = Constants.floatLimit
+       val jumpLimit = Constants.jumpLimit
+
+       (* destructuring functions *)
+       fun getX ({x, ...}: t) = x
+       fun getY ({y, ...}: t) = y
+
+       fun getXAxis ({xAxis, ...}: t) = xAxis
+       fun getYAxis ({yAxis, ...}: t) = yAxis
+
+       val W_X = EnemyPatch.W_X
+       val W_Y = EnemyPatch.W_Y
+       val W_Y_AXIS = EnemyPatch.W_Y_AXIS
+     end)