[英]How can I extract std::string object via boost spirit
我有以下代碼:
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>
#include <boost/spirit/include/qi.hpp>
#include <iostream>
#include <string>
struct function
{
std::string ret_type;
std::string name;
};
BOOST_FUSION_ADAPT_STRUCT(
::function,
(std::string, ret_type)
(std::string, name)
)
template <typename Iterator>
struct function_parser : boost::spirit::qi::grammar<Iterator, function(), boost::spirit::qi::ascii::space_type>
{
function_parser() : function_parser::base_type(start)
{
using boost::spirit::qi::ascii::char_;
using boost::spirit::qi::int_;
start %= +char_ >> +char_;
}
boost::spirit::qi::rule<Iterator, function(), boost::spirit::qi::ascii::space_type> start;
};
int main()
{
std::string input_data("void foo");
function fn;
auto itr = input_data.begin();
auto end = input_data.end();
function_parser<decltype(itr)> g;
bool res = boost::spirit::qi::phrase_parse(itr, end, g, boost::spirit::ascii::space, fn);
if (res && itr == end)
{
std::cout << boost::fusion::tuple_open('[');
std::cout << boost::fusion::tuple_close(']');
std::cout << boost::fusion::tuple_delimiter(", ");
std::cout << "Parsing succeeded\n";
std::cout << "got: " << boost::fusion::as_vector(fn) << std::endl;
}
else
{
std::cout << "Parsing failed \n";
}
}
產量
解析失敗
我究竟做錯了什么? 我該如何解決?
+char_
吃掉所有輸入! 現在,下一個
+char_
至少需要一個字符,但不存在(第一個kleen加上它),因此解析失敗。
我建議改為:
using namespace boost::spirit::qi;
start = lexeme[+graph] >> lexeme[+graph];
該文檔應該能夠告訴您它的作用(我希望。沒有時間詳細闡述)
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