Eff (programming language)

Eff is a general-purpose, high-level, multi-paradigm, functional programming language similar in syntax to OCaml which integrates the functions of algebraic effect handlers.^{[1] [2]}

effect Get_next : (unit -> unit) option
effect Add_to_queue : (unit -> unit) -> unit
let queue initial = handler
 | effect Get_next k ->
 ( fun queue -> match queue with
 | [] -> (continue k None) []
 | hd::tl -> (continue k (Some hd)) tl )
 | effect (Add_to_queue y) k -> ( fun queue -> (continue k ()) (queue @ [y]))
 | x -> ( fun _ -> x)
 | finally x -> x initial
;;

• Official website
• Eff on GitHub