Source file async_kernel.ml

(** Contains Async's core data structures, like {{!Async_kernel.Deferred}[Deferred]},
    {{!Async_kernel.Ivar}[Ivar]}, and {{!Async_kernel.Clock_intf.Clock}[Clock]}.

    [Async_kernel] is designed to depend only on {{!Core}[Core]} and so is more
    platform-independent. *)

open! Core
open! Import
module Async_kernel_config = Async_kernel_config
module Async_kernel_require_explicit_time_source = Require_explicit_time_source
module Async_kernel_scheduler = Async_kernel_scheduler
module Bvar = Bvar
module Clock_ns = Clock_ns
module Condition = Async_condition
module Deferred = Deferred
module Execution_context = Execution_context
module Gc = Async_gc
module Invariant = Async_invariant
module Ivar = Ivar
module Lazy_deferred = Lazy_deferred
module Monad_sequence = Monad_sequence
module Monitor = Monitor
module Mvar = Mvar
module Pipe = Pipe
module Priority = Priority
module Sequencer = Throttle.Sequencer
module Stream = Async_stream
module Synchronous_time_source = Synchronous_time_source
module Tail = Tail
module Throttle = Throttle
module Time_source = Time_source


(** {2 Toplevel functions }

    The functions below are broadly useful when writing Async programs, and so are made
    available at the toplevel. *)


let after = Clock_ns.after
let at = Clock_ns.at
let catch = Monitor.catch
let choice = Deferred.choice
let choose = Deferred.choose
let don't_wait_for = Deferred.don't_wait_for
let every = Clock_ns.every
let never = Deferred.never
let schedule = Scheduler.schedule
let schedule' = Scheduler.schedule'
let try_with = Monitor.try_with
let upon = Deferred.upon
let with_timeout = Clock_ns.with_timeout
let within = Scheduler.within
let within' = Scheduler.within'

(** {2 Infix operators and [Let_syntax] support} *)

include (Deferred : Monad.Infix with type 'a t := 'a Deferred.t)

(** equivalent to {!Deferred.upon}. *)
let ( >>> ) = Deferred.Infix.( >>> )

(** equivalent to {!Deferred.Result.bind}. *)
let ( >>=? ) = Deferred.Result.( >>= )

(** equivalent to {!Deferred.Result.map}. *)
let ( >>|? ) = Deferred.Result.( >>| )

include Deferred.Let_syntax

(**/**)

(** The modules in [Async_kernel_private] are used for constructing and testing Async, and
    should not otherwise be used. *)
module Async_kernel_private = struct
  module Debug = Debug
  module Ivar0 = Ivar0
  module Ivar_filler = Ivar_filler
  module Job = Job
  module Stack_or_counter = Stack_or_counter
end

(**/**)

(* This test must be in this library, because it requires [return] to be inlined.  Moving
   it to another library will cause it to break with [X_LIBRARY_INLINING=false]. *)
let%test_unit "[return ()] does not allocate" =
  let w1 = Gc.minor_words () in
  ignore (Sys.opaque_identity (return ()) : _ Deferred.t);
  ignore (Sys.opaque_identity (Deferred.return ()) : _ Deferred.t);
  ignore (Sys.opaque_identity (Deferred.Let_syntax.return ()) : _ Deferred.t);
  ignore (Sys.opaque_identity (Deferred.Let_syntax.Let_syntax.return ()) : _ Deferred.t);
  let w2 = Gc.minor_words () in
  [%test_result: int] w2 ~expect:w1
;;