Module `Lwt_result`Source

Explicit error handling

since 2.6.0

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

Sourcetype (+'a, +'b) t = ('a, 'b) result Lwt.t

Sourceval return : 'a -> ('a, _) t

Sourceval fail : 'b -> (_, 'b) t

Sourceval lift : ('a, 'b) result -> ('a, 'b) t

Sourceval ok : 'a Lwt.t -> ('a, _) t

Sourceval error : 'b Lwt.t -> (_, 'b) t

since 5.6.0

Sourceval 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

Sourceval 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.

Sourceval map : ('a -> 'b) -> ('a, 'e) t -> ('b, 'e) t

Sourceval map_error : ('e1 -> 'e2) -> ('a, 'e1) t -> ('a, 'e2) t

since 5.6.0

Sourceval bind : ('a, 'e) t -> ('a -> ('b, 'e) t) -> ('b, 'e) t

Sourceval bind_error : ('a, 'e1) t -> ('e1 -> ('a, 'e2) t) -> ('a, 'e2) t

since 5.6.0

Sourceval bind_lwt : ('a, 'e) t -> ('a -> 'b Lwt.t) -> ('b, 'e) t

Sourceval bind_lwt_error : ('a, 'e1) t -> ('e1 -> 'e2 Lwt.t) -> ('a, 'e2) t

since 5.6.0

Sourceval bind_result : ('a, 'e) t -> ('a -> ('b, 'e) result) -> ('b, 'e) t

Sourceval both : ('a, 'e) t -> ('b, 'e) t -> ('a * 'b, 'e) t

Lwt.both p_1 p_2 returns a promise that is pending until both promises p_1 and p_2 become resolved. If only p_1 is Error e, the promise is resolved with Error e, If only p_2 is Error e, the promise is resolved with Error e, If both p_1 and p_2 resolve with Error _, the promise is resolved with the error that occurred first.

Sourceval iter : ('a -> unit Lwt.t) -> ('a, 'e) t -> unit Lwt.t

iter f r is f v if r is a promise resolved with Ok v, and Lwt.return_unit otherwise.

since Lwt 5.6.0

Sourceval iter_error : ('e -> unit Lwt.t) -> ('a, 'e) t -> unit Lwt.t

iter_error f r is f v if r is a promise resolved with Error v, and Lwt.return_unit otherwise.

since Lwt 5.6.0

Sourcemodule Infix : sig ... end

Sourcemodule Let_syntax : sig ... end

Sourcemodule Syntax : sig ... end

include module type of Infix

Sourceval (>|=) : ('a, 'e) t -> ('a -> 'b) -> ('b, 'e) t

Sourceval (>>=) : ('a, 'e) t -> ('a -> ('b, 'e) t) -> ('b, 'e) t

Deprecated

Sourceval map_err : ('e1 -> 'e2) -> ('a, 'e1) t -> ('a, 'e2) t

deprecated
Alias to map_error since 5.6.0.

Sourceval bind_lwt_err : ('a, 'e1) t -> ('e1 -> 'e2 Lwt.t) -> ('a, 'e2) t

deprecated
Alias to bind_lwt_error since 5.6.0.

Install

Dune Dependency

Authors

Maintainers

Sources

doc/lwt/Lwt_result/index.html

Module `Lwt_result`Source

Deprecated

package lwt

Install

Dune Dependency

Authors

Maintainers

Sources

doc/lwt/Lwt_result/index.html

Module Lwt_resultSource

Deprecated

Module `Lwt_result`Source