Module Error

module Error: Error

type t

include Sexpable.S

include Binable.S

val to_sexp_hum : t -> Sexplib.Sexp.t

to_sexp_hum t returns t formatted as sexp that aims to be readable. This loses information about the structure of the error, so if the result is converted back using t_of_sexp, it will not be able to pretty print as nicely. That is, the following equalities do not necessarily hold:

to_sexp_hum (t_of_sexp (to_sexp_hum t)) = to_sexp_hum t to_string_hum (t_of_sexp (to_sexp_hum t)) = to_string_hum t

val to_string_hum : t -> string

might be an expensive operation

val of_string : string -> t

val of_lazy : string Lazy.t -> t

Be careful that the body of the lazy or thunk does not access mutable data, since it will only be called at an undetermined later point.

val of_thunk : (unit -> string) -> t

val create : string -> 'a -> ('a -> Sexplib.Sexp.t) -> t

For create msg z sexp_of_z, be careful to use only immutable values for z, or be aware that z will be lazily converted to a sexp at a later point in time, which will pick up the then-current state of z.

Functions for transforming errors

val tag : t -> string -> t

val tag_arg : t -> string -> 'a -> ('a -> Sexplib.Sexp.t) -> t

val of_list : ?trunc_after:int -> t list -> t

val of_exn : ?backtrace:[ `Get | `This of string ] -> exn -> t

val to_exn : t -> exn

val raise : t -> 'a

val failwiths : string -> 'a -> ('a -> Sexplib.Sexp.t) -> 'b

failwiths message value sexp_of_value raises an exception with the supplied message and value, by constructing an Error.t and using Error.raise. As usual, the sexp_of_value is only applied when the value is converted to a sexp or a string. So, if you mutate value in between the time you call failwiths and the time the error is displayed, those mutations will be reflected in the error message.

failwiths s a f = Error.raise (Error.create s a f)

val pp : Format.formatter -> t -> unit