Parse

`sig
val implementation : Stdlib.Lexing.lexbuf -> Parsetree.structure
val interface : Stdlib.Lexing.lexbuf -> Parsetree.signature
val toplevel_phrase : Stdlib.Lexing.lexbuf -> Parsetree.toplevel_phrase
val use_file : Stdlib.Lexing.lexbuf -> Parsetree.toplevel_phrase list
val core_type : Stdlib.Lexing.lexbuf -> Parsetree.core_type
val expression : Stdlib.Lexing.lexbuf -> Parsetree.expression
val pattern : Stdlib.Lexing.lexbuf -> Parsetree.pattern
val longident : Stdlib.Lexing.lexbuf -> Longident.t
val val_ident : Stdlib.Lexing.lexbuf -> Longident.t
val constr_ident : Stdlib.Lexing.lexbuf -> Longident.t
val simple_module_path : Stdlib.Lexing.lexbuf -> Longident.t
val extended_module_path : Stdlib.Lexing.lexbuf -> Longident.t
val type_ident : Stdlib.Lexing.lexbuf -> Longident.t
end`