1[#getting_started_38] 2 3 #include <boost/metaparse/fail_at_first_char_expected.hpp> 4 #include <boost/metaparse/first_of.hpp> 5 struct plus_exp4 : first_of< foldl_start_with_parser< sequence<one_of<plus_token, minus_token>, mult_exp6>, mult_exp6, boost::mpl::quote2<binary_op> >, fail_at_first_char_expected< sequence<one_of<plus_token, minus_token>, mult_exp6> > > {}; 6 using exp_parser21 = build_parser<plus_exp4>; 7 8