module Ivar

: sig

A write-once cell that can be empty or full (i.e. hold a single value).

One can read an ivar to obtain a deferred that becomes determined when the ivar is filled. An ivar is similar to an 'a option ref, except it is an error to fill an already full ivar.

type 'a t

type 'a ivar = 'a t

include Core.Std.Invariant.S1 with type 'a t := 'a t

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

equal t t' is physical equality of t and t'.

val create : unit -> 'a t

create () returns an empty ivar, create_full, a full one.

val create_full : 'a -> 'a t

val fill : 'a t -> 'a -> unit

fill t v fills t with value v if t was empty. If t was full, fill raises an exception.

It is guaranteed that immediately after calling fill t, is_some (Deferred.peek (read t)).

val fill_if_empty : 'a t -> 'a -> unit

fill_if_empty t v fills t with v if t is currently empty. If t is full, then fill_if_empty does nothing.

val is_empty : 'a t -> bool

is_empty t returns true if t is empty

val is_full : 'a t -> bool

is_full t returns true if t is full

module Deferred : sig

The Deferred module exposed here is for Async's internal use only.

type +'a t

module Handler : sig

type 'a t

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

end

val create : ('a ivar -> unit) -> 'a t

val peek : 'a t -> 'a option

val is_determined : _ t -> bool

val return : 'a -> 'a t

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

val bind : 'a t -> ('a -> 'b t) -> 'b t

val add_handler : 'a t -> ('a -> unit) -> Execution_context.t -> 'a Handler.t

val remove_handler : 'a t -> 'a Handler.t -> unit

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

end

val read : 'a t -> 'a Deferred.t

read t returns a deferred that becomes enabled with value v after the ivar is filled with v.

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

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

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

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

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

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

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

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

end