SteveGilham

type Point = { mutable x: int; mutable y: int }
              with member p.move q = p.x <- p.x + q.x;
                                     p.y <- p.y + q.y
let makePoint x y = { x = x; y = y }

SteveGilham

type IPoint
     = interface
           abstract x: int;
           abstract y: int;
           abstract move: IPoint -> unit
       end 

SteveGilham

type Point
     = class
           val mutable vx: int;
           val mutable vy: int;
           new(x,y) = { vx = x; vy = y }
           interface IPoint
                with member p.move q = p.vx <- p.vx + q.x;
                                       p.vy <- p.vy + q.y
                     member p.x = p.vx
                     member p.y = p.vy

SteveGilham

type Point(x,y)
     = class
           let mutable vx = x
           let mutable vy = y
           interface IPoint
                with member p.move q = vx <- vx + q.x;
                                       vy <- vy + q.y
                     member p.x = vx
                     member p.y = vy
       end

SteveGilham

[<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

SteveGilham

// Raise an ArgumentException:
invalid_arg "list must not be empty"
// Raise a FailureException:
failwith "internal error"

SteveGilham

raise (InvalidOperationException("help!"))

SteveGilham

exception Special of int
raise (Special 99)

SteveGilham

exception EmptyList of string
let rec folds g x
    = match x
      with [] -> raise (EmptyList "folds")
         | [x] -> x
         | h::t -> g h (folds g t)
try folds (fun x y -> x + y) []
with EmptyList m -> stdout.WriteLine(m);
     0

SteveGilham

let resource = getResource()
in try folds (useResource resource) []
   with EmptyList m -> stdout.WriteLine(m);
        rethrow()
   finally releaseResource resource