我在遵循Spirit文档中的教程,但是我卡在这里了:
#include <iostream>
#include <string>
#include <boost/spirit/include/qi.hpp>
template <typename Iterator>
bool parse_numbers(Iterator first, Iterator last, double &sum)
{
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
namespace ph = boost::phoenix;
bool r = qi::phrase_parse(
first,
last,
// begin grammar
(
qi::double_[ph::ref(sum) = qi::_1] >> *(',' >> qi::double_[ph::ref(sum) += qi::_1])
)
// end grammar
, ascii::space
);
if (first != last)
return false;
return true;
}
int main(int argc, char **argv)
{
std::string str = argv[1];
double sum;
bool result = parse_numbers(str.begin(), str.end(), sum);
if (result) {
std::cout << "Sum: " << sum << std::endl;
return 0;
}
std::cout << "Invalid Input" << std::endl;
return 1;
}
当我编译它时,显示出以下错误:
$ c++ spirit-test.c++
spirit-test.c++: In function ‘bool parse_numbers(Iterator, Iterator, double&) [with Iterator = __gnu_cxx::__normal_iterator<char*, std::basic_string<char> >]’:
spirit-test.c++:32:57: instantiated from here
spirit-test.c++:21:2: error: no match for ‘operator+=’ in ‘boost::phoenix::ref [with T = double](((double&)((double*)sum))) += boost::spirit::_1’
spirit-test.c++:21:2: error: no match for ‘operator=’ in ‘boost::phoenix::ref [with T = double](((double&)((double*)sum))) = boost::spirit::_1’
/usr/include/boost/spirit/home/phoenix/core/actor.hpp:143:16: note: candidate is: boost::phoenix::actor<Eval>& boost::phoenix::actor<Eval>::operator=(const boost::phoenix::actor<Eval>&) [with Eval = boost::phoenix::reference<double>, boost::phoenix::actor<Eval> = boost::phoenix::actor<boost::phoenix::reference<double> >]
有什么问题吗?
" . . . "
(4个前导空格)而不是<code>
进行固定格式。 - phoojiM-x increase-indent
。使用<code>
,所有在<
和>
内的短语都会消失,所以你的代码看起来比实际上更错误(没有任何模板参数):) - phooji