lwt

Promises, concurrency, and parallelized I/O
package lwt
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Library lwt
Module Lwt_result

This module provides helpers for values of type ('a, 'b) result Lwt.t. The module is experimental and may change in the future.

type (+'a, +'b) t = ( 'a, 'b ) Result.result Lwt.t
val return : 'a -> ( 'a, _ ) t
val fail : 'b -> ( _, 'b ) t
val lift : ( 'a, 'b ) Result.result -> ( 'a, 'b ) t
val ok : 'a Lwt.t -> ( 'a, _ ) t
val catch : 'a Lwt.t -> ( 'a, exn ) t

catch x behaves like return y if x evaluates to y, and like fail e if x raises e

val get_exn : ( 'a, exn ) t -> 'a Lwt.t

get_exn is the opposite of catch: it unwraps the result type, returning the value in case of success, calls Lwt.fail in case of error.

val map : ( 'a -> 'b ) -> ( 'a, 'e ) t -> ( 'b, 'e ) t
val map_err : ( 'e1 -> 'e2 ) -> ( 'a, 'e1 ) t -> ( 'a, 'e2 ) t
val bind : ( 'a, 'e ) t -> ( 'a -> ( 'b, 'e ) t ) -> ( 'b, 'e ) t
val bind_lwt : ( 'a, 'e ) t -> ( 'a -> 'b Lwt.t ) -> ( 'b, 'e ) t
val bind_lwt_err : ( 'a, 'e1 ) t -> ( 'e1 -> 'e2 Lwt.t ) -> ( 'a, 'e2 ) t
val bind_result : ( 'a, 'e ) t -> ( 'a -> ( 'b, 'e ) Result.result ) -> ( 'b, 'e ) t
module Infix : sig ... end
include module type of Infix
val (>|=) : ( 'a, 'e ) t -> ( 'a -> 'b ) -> ( 'b, 'e ) t
val (>>=) : ( 'a, 'e ) t -> ( 'a -> ( 'b, 'e ) t ) -> ( 'b, 'e ) t