module Sub:sig..end
typet =string * int * int
val make : string -> int -> len:int -> t
val full : string -> tval copy : t -> stringval underlying : t -> string
val sub : t -> int -> int -> tval get : t -> int -> charget s i gets the i-th element, or failsInvalid_argument if the index is not within 0... length -1include CCString.S