如何从Spirit :: Qi规则访问boost :: variant成员？
我无法找到一种正确的方法如何在我的Spirit-Qi语法中使用boost :: phoenix访问boost :: variant的成员。这是一个简单的例子，我正在努力实现。 （我的整个语法要复杂得多，这是我测试提到的问题的简单片段）。
namespace ph = boost::phoenix;
typedef boost::variant<std::string,int> VariantType;
typedef std::list<VariantType> TlstVariants;
rule<Iterator, void(TlstVariants&), Skipper> rule1;
rule1 =
qi::eps [ ph::push_back(qi::_r1, ph::construct<int>(2)) ]
>> qi::eps [ ph::get<int>(ph::back(qi::_r1)) = ph::val(3) ] //THIS IS EXAMPLE OF WHAT I NEED
;
TlstVariants lstVals;
ExecuteParser("5",rule1( ph::ref(lstVals) ));
BOOST_FOREACH( VariantType &val, lstVals )
{
std::cout << val.which() << " - " << val;
}
qi::rule<Iterator, void(structTest&), Skipper> rule_child;
rule =
qi::lit("test") [ph::push_back(sp::_r1, ph::construct<structTest>())]
> qi::lit('(')
> rule_child( ph::get<structTest>(ph::back(sp::_r1)) )
> qi::lit(')')
...
没有找到相关结果
已邀请:
2 个回复
荒劫娇噬
的一个。#include <boost/variant.hpp> #include <boost/spirit/include/phoenix.hpp> template <typename Result> struct get_impl { template <typename T> struct result { typedef Result type; }; template <BOOST_VARIANT_ENUM_PARAMS(typename T)> Result operator()(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& v) const { return boost::get<Result>(v); } }; ph::function<get_impl<int> > const get_int = get_impl<int>();骇毖煽洁铂
template <typename Result, typename Inner> struct get_impl { template <typename T> struct result { typedef Result type; }; template <BOOST_VARIANT_ENUM_PARAMS(typename T)> Result operator()(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> & v) const { return boost::get<Inner>(v); } };typedef boost::variant<std::string,int> VariantType; qi::rule<DG_Iterator, void(VariantType&), DG_Skipper> rule1; ph::function<get_impl<int,int> > const get_int = get_impl<int, int>(); ph::function<get_impl<int&,int> > const get_int_ref = get_impl<int&,int>(); rule1 = qi::eps [ std::cout << ph::val("variant=") << qi::_r1 << ph::val("n") ] >> qi::eps [ std::cout << ph::val("before=") << get_int(qi::_r1) << ph::val("n") ] >> qi::eps [ get_int_ref(qi::_r1) = ph::val(7) ] >> qi::eps [ std::cout << ph::val("after=") << get_int(qi::_r1) << ph::val("n") ] ; VariantType val(2134); TestSimpleRuleValidity("x",rule1( ph::ref(val) ), true); std::cout << val << "n";