lwt

Promises, concurrency, and parallelized I/O
Library lwt
Module Lwt . Infix
val (>>=) : 'a t -> ( 'a -> 'b t ) -> 'b t

p >>= f is the same as Lwt.bind p f. It requires Lwt.Infix to be opened in scope:

open Lwt.Infix

let () =
  Lwt_main.run
    (Lwt_io.(read_line stdin) >>= Lwt_io.printl)

(* ocamlfind opt -linkpkg -package lwt.unix code.ml && ./a.out *)

It is recommended to use the PPX let%lwt syntax instead. This operator is the next-best choice. It is frequently found while reading existing Lwt code.

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

p >|= f is the same as Lwt.map f p. It requires Lwt.Infix to be opened in scope.

open Lwt.Infix

let () =
  Lwt_main.run
    (Lwt_io.(read_line stdin) >|= ignore)

(* ocamlfind opt -linkpkg -package lwt.unix code.ml && ./a.out *)
val (<&>) : unit t -> unit t -> unit t

p1 <&> p2 is the same as Lwt.join [p1; p2]. It requires Lwt.Infix to be opened in scope.

Unlike with Lwt.bind and Lwt.map, there are no problems with explicit Lwt.join syntax, so using this operator is not recommended.

val (<?>) : 'a t -> 'a t -> 'a t

p1 <?> p2 is the same as Lwt.choose [p1; p2]. It requires Lwt.Infix to be opened in scope.

Unlike with Lwt,bind and Lwt.join, there are no problems with explicit Lwt.choose syntax, so using this operator is not recommended.

Futhermore, most users actually need Lwt.pick instead of Lwt.choose.

val (=<<) : ( 'a -> 'b t ) -> 'a t -> 'b t

f =<< p is the same as Lwt.bind p f. It requires Lwt.Infix to be opened in scope.

This operator is obscure and its use is discouraged. It is the same as p >>= f.

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

f =|< p is the same as Lwt.map f p. It requires Lwt.Infix to be opened in scope.

This operator is obscure and its use is discouraged. It is the same as p >|= f.