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open StdlibShim
module type Param =
sig
type env
end
module type S =
sig
include Param
val read : unit -> env
val scope : (env -> env) -> (unit -> 'a) -> 'a
val run : env:env -> (unit -> 'a) -> 'a
end
module Make (P : Param) =
struct
include P
type _ Effect.t += Read : env Effect.t
let read () = Effect.perform Read
let run ~(env:env) f =
let open Effect.Deep in
try_with f ()
{ effc = fun (type a) (eff : a Effect.t) ->
match eff with
| Read -> Option.some @@ fun (k : (a, _) continuation) ->
continue k env
| _ -> None }
let scope f c = run ~env:(f @@ read ()) c
end