Meta_conv.Resulttype ('a, 'error) t = ('a, 'error) resultmonadic ops
val fail : 'error -> ('a, 'error) tval catch : (fail:('error -> 'exn) -> 'a) -> ('a, 'error) tval catch_exn : (unit -> 'a) -> ('a, exn) tval result : ('a -> 'b) -> ('error -> 'b) -> ('a, 'error) t -> 'bsame as Haskell's either
module Open : sig ... end