Module Base.Either

type ('f, 's) t =
| First of 'f
| Second of 's
val compare : ('f -> 'f -> int) -> ('s -> 's -> int) -> ('f, 's) t -> ('f, 's) t -> int
val hash_fold_t : (Hash.state -> 'f -> Hash.state) -> (Hash.state -> 's -> Hash.state) -> Hash.state -> ('f, 's) t -> Hash.state
include Sexpable.S2 with type ('f, 's) t := ('f, 's) t
val t_of_sexp : (Sexplib0.Sexp.t -> 'a) -> (Sexplib0.Sexp.t -> 'b) -> Sexplib0.Sexp.t -> ('a, 'b) t
val sexp_of_t : ('a -> Sexplib0.Sexp.t) -> ('b -> Sexplib0.Sexp.t) -> ('a, 'b) t -> Sexplib0.Sexp.t
include Invariant.S2 with type ('a, 'b) t := ('a, 'b) t
val invariant : ('a -> unit) -> ('b -> unit) -> ('a, 'b) t -> unit
val swap : ('f, 's) t -> ('s, 'f) t
val value : ('a, 'a) t -> 'a
val iter : ('a, 'b) t -> first:('a -> unit) -> second:('b -> unit) -> unit
val value_map : ('a, 'b) t -> first:('a -> 'c) -> second:('b -> 'c) -> 'c
val map : ('a, 'b) t -> first:('a -> 'c) -> second:('b -> 'd) -> ('c, 'd) t
val equal : ('f -> 'f -> bool) -> ('s -> 's -> bool) -> ('f, 's) t -> ('f, 's) t -> bool
module type Focused = sig ... end
module First : Focused with type ('a, 'b) t = ('a, 'b) t
module Second : Focused with type ('a, 'b) t = ('b, 'a) t
val is_first : (_, _) t -> bool
val is_second : (_, _) t -> bool
val first : 'f -> ('f, _) t

first and second are First.return and Second.return.

val second : 's -> (_, 's) t