Lexer

`sig
val init : unit -> unit
val token : Lexing.lexbuf -> Parser.token
val skip_hash_bang : Lexing.lexbuf -> unit
type error =
Illegal_character of char
| Illegal_escape of string
| Unterminated_comment of Location.t
| Unterminated_string
| Unterminated_string_in_comment of Location.t * Location.t
| Keyword_as_label of string
| Invalid_literal of string
| Invalid_directive of string * string option
exception Error of Lexer.error * Location.t
val report_error : Format.formatter -> Lexer.error -> unit
val in_comment : unit -> bool
val in_string : unit -> bool
val print_warnings : bool Pervasives.ref
val handle_docstrings : bool Pervasives.ref
val comments : unit -> (string * Location.t) list
val token_with_comments : Lexing.lexbuf -> Parser.token
val set_preprocessor :
(unit -> unit) ->
((Lexing.lexbuf -> Parser.token) -> Lexing.lexbuf -> Parser.token) ->
unit
end`