`sig
type t = bytes
external length : BatBytes.t -> int = "%string_length"
external get : BatBytes.t -> int -> char = "%string_safe_get"
external set : BatBytes.t -> int -> char -> unit = "%string_safe_set"
external create : int -> BatBytes.t = "caml_create_string"
val make : int -> char -> BatBytes.t
val init : int -> (int -> char) -> BatBytes.t
val empty : BatBytes.t
val copy : BatBytes.t -> BatBytes.t
val of_string : string -> BatBytes.t
val to_string : BatBytes.t -> string
val sub : BatBytes.t -> int -> int -> BatBytes.t
val sub_string : BatBytes.t -> int -> int -> string
val extend : BatBytes.t -> int -> int -> BatBytes.t
val fill : BatBytes.t -> int -> int -> char -> unit
val blit : BatBytes.t -> int -> BatBytes.t -> int -> int -> unit
val blit_string : string -> int -> BatBytes.t -> int -> int -> unit
val concat : BatBytes.t -> BatBytes.t list -> BatBytes.t
val cat : BatBytes.t -> BatBytes.t -> BatBytes.t
val iter : (char -> unit) -> BatBytes.t -> unit
val iteri : (int -> char -> unit) -> BatBytes.t -> unit
val map : (char -> char) -> BatBytes.t -> BatBytes.t
val mapi : (int -> char -> char) -> BatBytes.t -> BatBytes.t
val trim : BatBytes.t -> BatBytes.t
val escaped : BatBytes.t -> BatBytes.t
val index : BatBytes.t -> char -> int
val rindex : BatBytes.t -> char -> int
val index_from : BatBytes.t -> int -> char -> int
val rindex_from : BatBytes.t -> int -> char -> int
val contains : BatBytes.t -> char -> bool
val contains_from : BatBytes.t -> int -> char -> bool
val rcontains_from : BatBytes.t -> int -> char -> bool
val uppercase : BatBytes.t -> BatBytes.t
val lowercase : BatBytes.t -> BatBytes.t
val capitalize : BatBytes.t -> BatBytes.t
val uncapitalize : BatBytes.t -> BatBytes.t
val compare : BatBytes.t -> BatBytes.t -> int
val unsafe_to_string : BatBytes.t -> string
val unsafe_of_string : string -> BatBytes.t
external unsafe_get : BatBytes.t -> int -> char = "%string_unsafe_get"
external unsafe_set : BatBytes.t -> int -> char -> unit
= "%string_unsafe_set"
external unsafe_blit :
BatBytes.t -> int -> BatBytes.t -> int -> int -> unit
= "caml_blit_string" "noalloc"
external unsafe_fill : BatBytes.t -> int -> int -> char -> unit
= "caml_fill_string" "noalloc"
end`