Ticket #6454: test_phoenix_if.cpp

#define BOOST_SPIRIT_USE_PHOENIX_V3
#include <boost/optional.hpp>
#include <boost/variant.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>

int main() {
  namespace qi = boost::spirit::qi;
  namespace phx = boost::phoenix;
  using namespace boost::phoenix::arg_names;

  typedef char* Iter;

  //Doesn't compile
  qi::rule<Iter, boost::optional<int>()> rule_a =
    (-qi::int_)[
      phx::if_(qi::_1)[
        phx::nothing
      ]
      //Uncomment next line and it compiles
      // , phx::nothing
    ]
  ;

  //Doesn't compile
  qi::rule<Iter, boost::optional< boost::variant<int, double> >() > rule_b =
    (qi::int_ | qi::double_ | qi::eps)[
      phx::if_(qi::_1)[
        phx::nothing
      ]
      //Uncomment next line and it compiles
      // , phx::nothing
    ]
  ;

  //Compiles
  qi::rule<Iter, boost::optional< boost::variant<int, double> >() > rule_c =
    (qi::int_ | qi::double_ | qi::eps)[
      phx::if_(phx::val(true))[
        phx::nothing
      ]
    ]
  ;

  //Compiles
  qi::rule<Iter, boost::optional<int>()> rule_d =
    (-qi::int_)[
      std::cout << qi::_1
    ]
  ;

  //Compiles
  phx::if_(arg1)[
    phx::nothing
  ]
  (boost::optional<int>(5));

  return 0;
}