image/svg+xml foldl_start_with_parser<plus_int, int_token, sum_op> BOOST_METAPARSE_STRING("11 + 13 + 3 + 21") int_token plus_int plus_int plus_int sum_op int_<24> sum_op int_<27> sum_op int_<48> parsing withfoldl_start_with_parser< plus_int, int_token, sum_op> int_<11> int_<13> int_<3> int_<21>