gistfile1.fs

[<AbstractClass>]
type AbstractPoint
     = class
           val mutable vx: int;
           val mutable vy: int;
           new(x,y) = { vx = x; vy = y }
           member p.x with get() = p.vx and set z = p.vx <- z
           member p.y with get() = p.vy and set z = p.vy <- z
           abstract move: AbstractPoint -> unit
       end
type Point'
     = class
           inherit AbstractPoint
           new(x,y) = { inherit AbstractPoint(x,y) }
           override p.move q = p.x <- p.x + q.x;
                               p.y <- p.y + q.y
       end

let p = Point'(2,3)
let q = Point'(1,2)
p.move(q)
p.x
p.y;;