type t = Jv.t

include (Jv.Id : Jv.CONV with type t := t)

let state_effect = Jv.get Jv.global "__CM__StateEffect"
let define () = Jv.call state_effect "define" [||]
let of_ t v = Jv.call t "of" [| v |]
let is instance t = Jv.to_bool (Jv.call instance "is" [| t |])
let value instance = Jv.get instance "value"