Ocamlnet 3 Reference Manual : Netulex.Ulexing

`sig
type lexbuf
exception Error
val from_ulb_lexbuf : Netulex.ULB.unicode_lexbuf -> Netulex.Ulexing.lexbuf
val lexeme_start : Netulex.Ulexing.lexbuf -> int
val lexeme_end : Netulex.Ulexing.lexbuf -> int
val lexeme_length : Netulex.Ulexing.lexbuf -> int
val lexeme : Netulex.Ulexing.lexbuf -> int array
val lexeme_char : Netulex.Ulexing.lexbuf -> int -> int
val sub_lexeme : Netulex.Ulexing.lexbuf -> int -> int -> int array
val utf8_lexeme : Netulex.Ulexing.lexbuf -> string
val utf8_sub_lexeme : Netulex.Ulexing.lexbuf -> int -> int -> string
val utf8_sub_lexeme_length : Netulex.Ulexing.lexbuf -> int -> int -> int
val start : Netulex.Ulexing.lexbuf -> unit
val next : Netulex.Ulexing.lexbuf -> int
val mark : Netulex.Ulexing.lexbuf -> int -> unit
val backtrack : Netulex.Ulexing.lexbuf -> int
end`