OCaml compiler library : Lexer

`sig
val init :
?keyword_edition:(int * int) option * string list -> unit -> unit
val token : Stdlib.Lexing.lexbuf -> Parser.token
val skip_hash_bang : Stdlib.Lexing.lexbuf -> unit
type error =
Illegal_character of char
| Illegal_escape of string * string option
| Reserved_sequence of string * string option
| Unterminated_comment of Location.t
| Unterminated_string
| Unterminated_string_in_comment of Location.t * Location.t
| Empty_character_literal
| Keyword_as_label of string
| Capitalized_label of string
| Invalid_literal of string
| Invalid_directive of string * string option
| Invalid_encoding of string
| Invalid_char_in_ident of Stdlib.Uchar.t
| Non_lowercase_delimiter of string
| Capitalized_raw_identifier of string
| Unknown_keyword of string
exception Error of Lexer.error * Location.t
val in_comment : unit -> bool
val in_string : unit -> bool
val is_keyword : string -> bool
val print_warnings : bool Stdlib.ref
val handle_docstrings : bool Stdlib.ref
val comments : unit -> (string * Location.t) list
val token_with_comments : Stdlib.Lexing.lexbuf -> Parser.token
val set_preprocessor :
(unit -> unit) ->
((Stdlib.Lexing.lexbuf -> Parser.token) ->
Stdlib.Lexing.lexbuf -> Parser.token) ->
unit
end`