Parse

`sig val implementation : Lexing.lexbuf -> Parsetree.structure val interface : Lexing.lexbuf -> Parsetree.signature val toplevel_phrase : Lexing.lexbuf -> Parsetree.toplevel_phrase val use_file : Lexing.lexbuf -> Parsetree.toplevel_phrase list val core_type : Lexing.lexbuf -> Parsetree.core_type val expression : Lexing.lexbuf -> Parsetree.expression val pattern : Lexing.lexbuf -> Parsetree.pattern end`