# Module Option

    module Option: sig .. end

Options form a monad, where `return x = Some x`, `(None >>= f) = None`, and `(Some x >>= f) = f x`.

    type 'a t = 'a option

    val typerep_of_t : 'a Typerep_lib.Std.Typerep.t -> 'a t Typerep_lib.Std.Typerep.t

    val typename_of_t : 'a Typerep_lib.Std.Typename.t -> 'a t Typerep_lib.Std.Typename.t

    include Container.S1

    include Invariant.S1

    include Monad.S

Options form a monad, where `return x = Some x`, `(None >>= f) = None`, and `(Some x >>= f) = f x`.

    val is_none : 'a t -> bool

`is_none t` returns true iff t = None.

    val is_some : 'a t -> bool

`is_some t` returns true iff t = Some x.

    val value_map : 'a t -> default:'b -> f:('a -> 'b) -> 'b

`value_map ~default ~f` is the same as `function Some x -> f x | None -> default`

    val map2 : 'a t -> 'b t -> f:('a -> 'b -> 'c) -> 'c t

`map2 o f` map 'a option and 'b option to a 'c option using ~f

    val call : 'a -> f:('a -> unit) t -> unit

`call x f` run optional function on argument

    val value : 'a t -> default:'a -> 'a

`value None ~default` = `default` `value (Some x) ~default` = `x`

    val value_exn : ?here:Source_code_position0.t ->
           ?error:Error.t -> ?message:string -> 'a t -> 'a

`value_exn (Some x)` = `x`. `value_exn None` raises an error whose contents contain the supplied `~here`, `~error`, and `message`, or a default message if none are supplied.

    val some : 'a -> 'a t

    val both : 'a t -> 'b t -> ('a * 'b) t

    val first_some : 'a t -> 'a t -> 'a t

    val some_if : bool -> 'a -> 'a t

    val merge : 'a t -> 'a t -> f:('a -> 'a -> 'a) -> 'a t

`merge a b ~f` merges together the values from `a` and `b` using `f`. If both `a` and `b` are `None`, returns `None`. If only one is `Some`, returns that one, and if both are `Some`, returns `Some` of the result of applying `f` to the contents of `a` and `b`.

    val filter : 'a t -> f:('a -> bool) -> 'a t

    val try_with : (unit -> 'a) -> 'a t

`try_with f` returns `Some x` if `f` returns `x` and `None` if `f` raises an exception. See `Result.try_with` if you'd like to know which exception.

    val compare : cmp:('a -> 'a -> int) -> 'a t -> 'a t -> int

Compares `None` as smaller than any `Some x`

    val equal : ('a -> 'a -> bool) -> 'a t -> 'a t -> bool

    val validate : none:unit Validate.check ->
           some:'a Validate.check -> 'a t Validate.check

    val t_of_sexp : (Sexplib.Sexp.t -> 'a) -> Sexplib.Sexp.t -> 'a t

    val sexp_of_t : ('a -> Sexplib.Sexp.t) -> 'a t -> Sexplib.Sexp.t

    val bin_t : 'a Bin_prot.Type_class.t -> 'a t Bin_prot.Type_class.t

    val bin_read_t : 'a Bin_prot.Read.reader -> 'a t Bin_prot.Read.reader

    val __bin_read_t__ : 'a Bin_prot.Read.reader -> (int -> 'a t) Bin_prot.Read.reader

    val bin_reader_t : 'a Bin_prot.Type_class.reader -> 'a t Bin_prot.Type_class.reader

    val bin_size_t : 'a Bin_prot.Size.sizer -> 'a t Bin_prot.Size.sizer

    val bin_write_t : 'a Bin_prot.Write.writer -> 'a t Bin_prot.Write.writer

    val bin_writer_t : 'a Bin_prot.Type_class.writer -> 'a t Bin_prot.Type_class.writer

Options form a monad, where `return x = Some x`, `(None >>= f) = None`, and `(Some x >>= f) = f x`.
`is_none t` returns true iff t = None.
`is_some t` returns true iff t = Some x.
`value_map ~default ~f` is the same as `function Some x -> f x | None -> default`
`map2 o f` map 'a option and 'b option to a 'c option using ~f
`call x f` run optional function on argument
`value None ~default` = `default` `value (Some x) ~default` = `x`
`value_exn (Some x)` = `x`. `value_exn None` raises an error whose contents contain the supplied `~here`, `~error`, and `message`, or a default message if none are supplied.
`merge a b ~f` merges together the values from `a` and `b` using `f`. If both `a` and `b` are `None`, returns `None`. If only one is `Some`, returns that one, and if both are `Some`, returns `Some` of the result of applying `f` to the contents of `a` and `b`.
`try_with f` returns `Some x` if `f` returns `x` and `None` if `f` raises an exception. See `Result.try_with` if you'd like to know which exception.
Compares `None` as smaller than any `Some x`