Module Base.Error

A lazy string, implemented with Info, but intended specifically for error messages.

type t = private Info.t

Serialization and comparison force the lazy message.

val compare : t -> t -> int
val equal : t -> t -> bool
val hash_fold_t : Hash.state -> t -> Hash.state
val hash : t -> Hash.hash_value
include Sexpable.S with type t := t
val t_of_sexp : Sexp.t -> t
val sexp_of_t : t -> Sexp.t
val invariant : t -> unit
val to_string_hum : t -> string

to_string_hum forces the lazy message, which might be an expensive operation.

to_string_hum usually produces a sexp; however, it is guaranteed that to_string_hum (of_string s) = s.

If this string is going to go into a log file, you may find it useful to ensure that the string is only one line long. To do this, use to_string_mach t.

val to_string_mach : t -> string

to_string_mach t outputs t as a sexp on a single line.

val to_string_hum_deprecated : t -> string

Old version (pre 109.61) of to_string_hum that some applications rely on.

Calls should be replaced with to_string_mach t, which outputs more parentheses and backslashes.

val of_string : string -> t
val of_lazy : string Lazy.t -> t
val of_thunk : (unit -> string) -> t
val of_lazy_t : t Lazy.t -> t
val create : ?⁠here:Caml.Lexing.position -> ?⁠strict:unit -> string -> 'a -> ('a -> Sexp.t) -> t

For create message a sexp_of_a, sexp_of_a a is lazily computed, when the info is converted to a sexp. So if a is mutated in the time between the call to create and the sexp conversion, those mutations will be reflected in the sexp. Use ~strict:() to force sexp_of_a a to be computed immediately.

val create_s : Sexp.t -> t
val createf : ('a, unit, string, t) Stdlib.format4 -> 'a

Constructs a t containing only a string from a format. This eagerly constructs the string.

val tag : t -> tag:string -> t

Adds a string to the front.

val tag_s : t -> tag:Sexp.t -> t

Adds a sexp to the front.

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

Adds a string and some other data in the form of an s-expression at the front.

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

Combines multiple infos into one.

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

of_exn and to_exn are primarily used with Error, but their definitions have to be here because they refer to the underlying representation.

~backtrace:`Get attaches the backtrace for the most recent exception. The same caveats as for Printexc.print_backtrace apply. ~backtrace:(`This s) attaches the backtrace s. The default is no backtrace.

val to_exn : t -> exn
val pp : Formatter.t -> t -> unit
module Internal_repr : sig ... end with type Internal_repr.info := t
val raise : t -> _

Note that the exception raised by this function maintains a reference to the t passed in.

val raise_s : Sexp.t -> _
val to_info : t -> Info.t
val of_info : Info.t -> t