ligo/lib_protocol_environment_sigs/v1/error_monad.mli

119 lines
4.3 KiB
OCaml

(**************************************************************************)
(* *)
(* Copyright (c) 2014 - 2017. *)
(* Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* *)
(* All rights reserved. No warranty, explicit or implicit, provided. *)
(* *)
(**************************************************************************)
(** Tezos Protocol Implementation - Error Monad *)
(** {2 Error classification} *************************************************)
(** Categories of error *)
type error_category =
[ `Branch (** Errors that may not happen in another context *)
| `Temporary (** Errors that may not happen in a later context *)
| `Permanent (** Errors that will happen no matter the context *)
]
(** Custom error handling for economic protocols. *)
type error = ..
val pp : Format.formatter -> error -> unit
(** A JSON error serializer *)
val error_encoding : error Data_encoding.t
val json_of_error : error -> Data_encoding.json
val error_of_json : Data_encoding.json -> error
(** For other modules to register specialized error serializers *)
val register_error_kind :
error_category ->
id:string -> title:string -> description:string ->
?pp:(Format.formatter -> 'err -> unit) ->
'err Data_encoding.t ->
(error -> 'err option) -> ('err -> error) ->
unit
(** Classify an error using the registered kinds *)
val classify_errors : error list -> error_category
(** {2 Monad definition} *****************************************************)
(** The error monad wrapper type, the error case holds a stack of
error, initialized by the first call to {!fail} and completed by
each call to {!trace} as the stack is rewinded. The most general
error is thus at the top of the error stack, going down to the
specific error that actually caused the failure. *)
type 'a tzresult = ('a, error list) result
(** A JSON serializer for result of a given type *)
val result_encoding : 'a Data_encoding.t -> 'a tzresult Data_encoding.encoding
(** Sucessful result *)
val ok : 'a -> 'a tzresult
(** Sucessful return *)
val return : 'a -> 'a tzresult Lwt.t
(** Erroneous result *)
val error : error -> 'a tzresult
(** Erroneous return *)
val fail : error -> 'a tzresult Lwt.t
(** Non-Lwt bind operator *)
val (>>?) : 'a tzresult -> ('a -> 'b tzresult) -> 'b tzresult
(** Bind operator *)
val (>>=?) : 'a tzresult Lwt.t -> ('a -> 'b tzresult Lwt.t) -> 'b tzresult Lwt.t
(** Lwt's bind reexported *)
val (>>=) : 'a Lwt.t -> ('a -> 'b Lwt.t) -> 'b Lwt.t
val (>|=) : 'a Lwt.t -> ('a -> 'b) -> 'b Lwt.t
(** To operator *)
val (>>|?) : 'a tzresult Lwt.t -> ('a -> 'b) -> 'b tzresult Lwt.t
(** Non-Lwt to operator *)
val (>|?) : 'a tzresult -> ('a -> 'b) -> 'b tzresult
(** Enrich an error report (or do nothing on a successful result) manually *)
val record_trace : error -> 'a tzresult -> 'a tzresult
(** Automatically enrich error reporting on stack rewind *)
val trace : error -> 'b tzresult Lwt.t -> 'b tzresult Lwt.t
(** Erroneous return on failed assertion *)
val fail_unless : bool -> error -> unit tzresult Lwt.t
(** {2 In-monad list iterators} **********************************************)
(** A {!List.iter} in the monad *)
val iter_s : ('a -> unit tzresult Lwt.t) -> 'a list -> unit tzresult Lwt.t
(** A {!List.map} in the monad *)
val map_s : ('a -> 'b tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
val map_p : ('a -> 'b tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
(** A {!List.map2} in the monad *)
val map2 :
('a -> 'b -> 'c tzresult) -> 'a list -> 'b list -> 'c list tzresult
(** A {!List.map2} in the monad *)
val map2_s :
('a -> 'b -> 'c tzresult Lwt.t) -> 'a list -> 'b list ->
'c list tzresult Lwt.t
(** A {!List.filter_map} in the monad *)
val filter_map_s : ('a -> 'b option tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
(** A {!List.fold_left} in the monad *)
val fold_left_s : ('a -> 'b -> 'a tzresult Lwt.t) -> 'a -> 'b list -> 'a tzresult Lwt.t
(** A {!List.fold_right} in the monad *)
val fold_right_s : ('a -> 'b -> 'b tzresult Lwt.t) -> 'a list -> 'b -> 'b tzresult Lwt.t