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Module Lazy_deferred = Async_kernel.Lazy_deferred

Signature

type 'a t
val create : (unit -> 'a Async_kernel.Deferred.t) -> 'a t

create f creates a new lazy deferred that will call f when it is forced.

val force : 'a t -> 'a Core_kernel.Std.Or_error.t Async_kernel.Deferred.t

force t forces evaluation of t and returns a deferred that becomes determined when the deferred computation becomes determined or raises.

val force_exn : 'a t -> 'a Async_kernel.Deferred.t
val wait : 'a t -> 'a Core_kernel.Std.Or_error.t Async_kernel.Deferred.t

wait t and wait_exn t waits for t to be forced. If no one ever calls force t, they will wait forever.

val wait_exn : 'a t -> 'a Async_kernel.Deferred.t
include Core_kernel.Std.Monad with type 'a t := 'a t
type 'a t
include Monad_intf.S_without_syntax with type 'a t := 'a t
type 'a t

A monad is an abstraction of the concept of sequencing of computations. A value of type 'a monad represents a computation that returns a value of type 'a.

include Monad_intf.Infix with type 'a t := 'a t
type 'a t
val (>>=) : 'a t -> ('a -> 'b t) -> 'b t

t >>= f returns a computation that sequences the computations represented by two monad elements. The resulting computation first does t to yield a value v, and then runs the computation returned by f v.

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

t >>| f is t >>= (fun a -> return (f a)).

module Monad_infix : Monad_intf.Infix with type 'a t := 'a t
val bind : 'a t -> ('a -> 'b t) -> 'b t

bind t f = t >>= f

val return : 'a -> 'a t

return v returns the (trivial) computation that returns v.

val map : 'a t -> f:('a -> 'b) -> 'b t

map t ~f is t >>| f.

val join : 'a t t -> 'a t

join t is t >>= (fun t' -> t').

val ignore_m : 'a t -> unit t

ignore_m t is map t ~f:(fun _ -> ()). ignore_m used to be called ignore, but we decided that was a bad name, because it shadowed the widely used Pervasives.ignore. Some monads still do let ignore = ignore_m for historical reasons.

val all : 'a t list -> 'a list t
val all_ignore : unit t list -> unit t
include Monad_intf.Syntax with type 'a t := 'a t
type 'a t
module Let_syntax : sig .. end
val bind' : 'a t -> ('a -> 'b Async_kernel.Deferred.t) -> 'b t

bind' differs from bind in that the supplied function produces an 'a Deferred.t rather than an 'a t.

Read-only operations.

val peek : 'a t -> 'a Core_kernel.Std.Or_error.t option

peek t = Deferred.peek (wait t)

val peek_exn : 'a t -> 'a option
val is_determined : _ t -> bool
val is_forced : _ t -> bool