Sdl.Rect
val create : x:int -> y:int -> w:int -> h:int -> rect
val x : rect -> int
val y : rect -> int
val w : rect -> int
val h : rect -> int
val set_x : rect -> int -> unit
val set_y : rect -> int -> unit
val set_w : rect -> int -> unit
val set_h : rect -> int -> unit