delimited.eff

(* This example is described in Section 6.11 of "Programming with Algebraic Effects and
   Handlers" by A. Bauer and M. Pretnar. *)

effect Shift : ((int -> int) -> int) -> int
(* Such operations are currently less usefull due to lack of polymorphism in
   current version of eff. In version 3.0 it is possible to have a polymorphic
   version. *)

let reset =
  let rec reset_handler () = handler
    | effect (Shift f) k -> with reset_handler () handle (f k)
  in
  reset_handler ()
;;

(* An example from http://lamp.epfl.ch/~rompf/continuations-icfp09.pdf *)

with reset handle
  perform (Shift (fun k -> k (k (k 7)))) * 2 + 1
;;

(* The yin-yang puzzle, see
   http://stackoverflow.com/questions/2694679/how-the-yin-yang-puzzle-works

   Warning: To run this example you have to turn off type checking:

        eff --no-types delimited.eff*)

(*
with reset handle
let yin = (fun k -> perform Print "@"; k) (perform Shift (fun k -> k k)) in
let yang = (fun k -> perform Print "*"; k) (perform Shift (fun k -> k k)) in
yin yang;;
*)