contCE.fs

#r @"packages\FSharpx.Core.1.8.41\lib\40\FSharpx.Core.dll"

open FSharpx.Continuation

type Location = float * float
type Radius = float
type Width = float
type Angle = float

type Primitive = 
    | Circle of Location * Radius
    | MultiPrimitive of Primitive List

let lengthContCE p =
  let rec loop x = cont {
    match x with
    | Circle(_, r) -> return (System.Math.PI * r * 2.)
    | MultiPrimitive [] -> return 0.
    | MultiPrimitive(h :: t) -> 
        let! hResult = loop h
        let! tResult = loop (MultiPrimitive t)
        return hResult + tResult
  }
  runCont (loop p) id (fun _ -> 0.)