ligo/src/lib_error_monad/error_monad_sig.ml
2019-02-20 14:03:44 +08:00

236 lines
9.4 KiB
OCaml

(*****************************************************************************)
(* *)
(* Open Source License *)
(* Copyright (c) 2018 Dynamic Ledger Solutions, Inc. <contact@tezos.com> *)
(* *)
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(* copy of this software and associated documentation files (the "Software"),*)
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(* in all copies or substantial portions of the Software. *)
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(** 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 *)
]
module type S = sig
type error = ..
(** Catch all error when 'serializing' an error. *)
type error += private Unclassified of string
(** Catch all error when 'deserializing' an error. *)
type error += private Unregistred_error of Data_encoding.json
val pp: Format.formatter -> error -> unit
val pp_print_error: Format.formatter -> error list -> unit
(** An 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
(** {2 Error documentation} ************************************************)
(** Error information *)
type error_info =
{ category : error_category ;
id : string ;
title : string ;
description : string ;
schema : Data_encoding.json_schema }
val pp_info: Format.formatter -> error_info -> unit
(** Retrieves information of registered errors *)
val get_registered_errors : unit -> error_info list
(** {2 Error classification} ***********************************************)
(** The error data type is extensible. Each module can register specialized
error serializers
[id] unique name of this error. Ex.: overflow_time_counter
[title] more readable name. Ex.: Overflow of time counter
[description] human readable description. Ex.: The time counter overflowed while computing delta increase
[pp] formatter used to pretty print additional arguments. Ex.: The time counter overflowed while computing delta increase. Previous value %d. Delta: %d
[encoder] [decoder] data encoding for this error. If the error has no value, specify Data_encoding.empty
*)
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 serializer for result of a given type *)
val result_encoding :
'a Data_encoding.t ->
'a tzresult Data_encoding.t
(** Sucessful result *)
val ok : 'a -> 'a tzresult
(** Sucessful return *)
val return : 'a -> 'a tzresult Lwt.t
(** Sucessful return of [()] *)
val return_unit : unit tzresult Lwt.t
(** Sucessful return of [None] *)
val return_none : 'a option tzresult Lwt.t
(** [return_some x] is a sucessful return of [Some x] *)
val return_some : 'a -> 'a option tzresult Lwt.t
(** Sucessful return of [[]] *)
val return_nil : 'a list tzresult Lwt.t
(** Sucessful return of [true] *)
val return_true : bool tzresult Lwt.t
(** Sucessful return of [false] *)
val return_false : bool 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
(** Same as record_trace, for unevaluated error *)
val record_trace_eval : (unit -> error tzresult) -> 'a tzresult -> 'a tzresult
(** Same as trace, for unevaluated Lwt error *)
val trace_eval : (unit -> error tzresult Lwt.t) -> 'b tzresult Lwt.t -> 'b tzresult Lwt.t
(** Erroneous return on failed assertion *)
val fail_unless : bool -> error -> unit tzresult Lwt.t
val fail_when : bool -> error -> unit tzresult Lwt.t
val unless : bool -> (unit -> unit tzresult Lwt.t) -> unit tzresult Lwt.t
val _when : bool -> (unit -> unit tzresult Lwt.t) -> unit tzresult Lwt.t
(* Usage: [_assert cond __LOC__ "<fmt>" ...] *)
val _assert :
bool -> string ->
('a, Format.formatter, unit, unit tzresult Lwt.t) format4 -> 'a
(** {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
val iter_p : ('a -> unit tzresult Lwt.t) -> 'a list -> unit tzresult Lwt.t
val iter2_p : ('a -> 'b -> unit tzresult Lwt.t) -> 'a list -> 'b list -> unit tzresult Lwt.t
val iteri2_p : (int -> 'a -> 'b -> unit tzresult Lwt.t) -> 'a list -> 'b 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
val mapi_s : (int -> 'a -> 'b tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
val mapi_p : (int -> '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
val map2_s :
('a -> 'b -> 'c tzresult Lwt.t) -> 'a list -> 'b list ->
'c list tzresult Lwt.t
val mapi2_s :
(int -> '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
val filter_map_p :
('a -> 'b option tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
(** A {!List.filter} in the monad *)
val filter_s :
('a -> bool tzresult Lwt.t) -> 'a list -> 'a list tzresult Lwt.t
val filter_p :
('a -> bool tzresult Lwt.t) -> 'a list -> 'a 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
(** A {!Lwt.join} in the monad *)
val join : unit tzresult Lwt.t list -> unit tzresult Lwt.t
(** Lazy values with retry-until success semantics *)
type 'a tzlazy
(** Create a {!tzlazy} value. *)
val tzlazy: (unit -> 'a tzresult Lwt.t) -> 'a tzlazy
(** [tzforce tzl] is either
(a) the remembered value carried by [tzl] if available
(b) the result of the callback/closure used to create [tzl] if successful,
in which case the value is remembered, or
(c) an error if the callback/closure used to create [tzl] is unsuccessful.
*)
val tzforce: 'a tzlazy -> 'a tzresult Lwt.t
end