module Strings: sig .. end
val set : string -> int -> char -> string
val create : int -> string
val init : int -> (int -> char) -> string
val fold_left : ('a -> char -> 'a) -> 'a -> string -> 'a
val nth : string -> int -> char option
val nth_is : string -> int -> char -> bool
val char_index_from : string -> int -> char -> int option
val char_rindex_from : string -> int -> char -> int option
val char_index_all : string -> char -> int list
val char_split : char -> string -> string list
val char_splitter : char -> string -> string list
val char_cut : char -> string -> (string * string) option
val char_rcut : char -> string -> (string * string) option
val starts_with : string -> string -> bool
val ends_with : string -> string -> bool
val sub_opt : string -> int -> int -> string option
val sub_is : string -> int -> int -> string -> bool
val str_split : string -> string -> string list
val str_cut : string -> string -> (string * string) option
val last_ofs : string -> int
val valid_ofs : string -> int -> bool
val string_index_from : string -> int -> string -> int option
val string_rindex_from : string -> int -> string -> int option
val string_index : string -> string -> int option
val string_rindex : string -> string -> int option