tezos-error-monad
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type error

This type is meant to be substituted/constrained. The intended use is along the following lines:

module Foo : sig include CORE include MONAD with type error := error end = struct ... end

See core.mli and monad.mli as examples.

type trace = error list

A trace is a stack of errors. It is implemented as an error list but such a list MUST NEVER be empty.

It is implemented as a concrete error list for backwards compatibility but future improvements might modify the type or render the type abstract.

val pp_print_error : Format.formatter -> trace -> unit
val trace_encoding : trace Data_encoding.t
val classify_errors : trace -> error_category
type 'a tzresult = ('a, trace) result

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.

val result_encoding : 'a Data_encoding.t -> 'a tzresult Data_encoding.t

A serializer for result of a given type

val ok : 'a -> 'a tzresult

Sucessful result

val return : 'a -> 'a tzresult Lwt.t

Sucessful return

val return_unit : unit tzresult Lwt.t

Sucessful return of ()

val return_none : 'a option tzresult Lwt.t

Sucessful return of None

val return_some : 'a -> 'a option tzresult Lwt.t

return_some x is a sucessful return of Some x

val return_nil : 'a list tzresult Lwt.t

Sucessful return of []

val return_true : bool tzresult Lwt.t

Sucessful return of true

val return_false : bool tzresult Lwt.t

Sucessful return of false

val error : error -> 'a tzresult

Erroneous result

val fail : error -> 'a tzresult Lwt.t

Erroneous return

val (>>?) : 'a tzresult -> ('a -> 'b tzresult) -> 'b tzresult

Non-Lwt bind operator

val (>>=?) : 'a tzresult Lwt.t -> ('a -> 'b tzresult Lwt.t) -> 'b tzresult Lwt.t

Bind operator

val (>>=) : 'a Lwt.t -> ('a -> 'b Lwt.t) -> 'b Lwt.t

Lwt's bind reexported

val (>|=) : 'a Lwt.t -> ('a -> 'b) -> 'b Lwt.t
val (>>|?) : 'a tzresult Lwt.t -> ('a -> 'b) -> 'b tzresult Lwt.t

To operator

val (>|?) : 'a tzresult -> ('a -> 'b) -> 'b tzresult

Non-Lwt to operator

val record_trace : error -> 'a tzresult -> 'a tzresult

Enrich an error report (or do nothing on a successful result) manually

val trace : error -> 'b tzresult Lwt.t -> 'b tzresult Lwt.t

Automatically enrich error reporting on stack rewind

val record_trace_eval : (unit -> error tzresult) -> 'a tzresult -> 'a tzresult

Same as record_trace, for unevaluated error

val trace_eval : (unit -> error tzresult Lwt.t) -> 'b tzresult Lwt.t -> 'b tzresult Lwt.t

Same as trace, for unevaluated Lwt error

val fail_unless : bool -> error -> unit tzresult Lwt.t

Erroneous return on failed assertion

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
val _assert : bool -> string -> ('a, Format.formatter, unit, unit tzresult Lwt.t) format4 -> 'a

In-monad list iterators

val iter_s : ('a -> unit tzresult Lwt.t) -> 'a list -> unit tzresult Lwt.t

A List.iter in the monad

val iter_p : ('a -> unit tzresult Lwt.t) -> 'a list -> unit tzresult Lwt.t
val iteri_p : (int -> '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
val map_s : ('a -> 'b tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t

A List.map in the monad

val rev_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
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
val mapi2_s : (int -> 'a -> 'b -> 'c tzresult Lwt.t) -> 'a list -> 'b list -> 'c list tzresult Lwt.t
val filter_map_s : ('a -> 'b option tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t

A List.filter_map in the monad

val filter_map_p : ('a -> 'b option tzresult Lwt.t) -> 'a list -> 'b list tzresult Lwt.t
val filter_s : ('a -> bool tzresult Lwt.t) -> 'a list -> 'a list tzresult Lwt.t

A List.filter in the monad

val filter_p : ('a -> bool tzresult Lwt.t) -> 'a list -> 'a list tzresult Lwt.t
val fold_left_s : ('a -> 'b -> 'a tzresult Lwt.t) -> 'a -> 'b list -> 'a tzresult Lwt.t

A List.fold_left in the monad

val fold_right_s : ('a -> 'b -> 'b tzresult Lwt.t) -> 'a list -> 'b -> 'b tzresult Lwt.t

A List.fold_right in the monad

val join : unit tzresult Lwt.t list -> unit tzresult Lwt.t

A Lwt.join in the monad