c++ - 从 Boost.Spirit.Qi 创建 shared_ptr

Question

我想使用 Spirit Qi 语法将文本解析为指向字符串的共享指针。实际上，我想将多元多项式解析为它们的系统，多项式中出现各种以前遇到的符号，但现在，让我们从文本解析为 std::shared_ptr<std::string> .

纠结了很久，在头文件中提取了这个小测试语法:

#define BOOST_SPIRIT_USE_PHOENIX_V3 1

#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <boost/bind.hpp>


namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;

template<typename Iterator>
struct SharedPtrParser :  qi::grammar<Iterator, std::shared_ptr<std::string>(), boost::spirit::ascii::space_type>
{
    SharedPtrParser() : SharedPtrParser(startrule)
    {
        startrule = qi::eps[ qi::_val = std::make_shared<std::string>()];
    }

    qi::rule<Iterator,std::shared_ptr<std::string>()> startrule;
};

以及它在 main 中的用法:

#include "shared_ptr_test.h"

int main()
{



    SharedPtrParser<std::string::const_iterator> C;

    std::string text = "thisissometext";

    auto iter = text.begin();
    auto end = text.end();


    std::shared_ptr<std::string> S;

    bool s = phrase_parse(iter, end, C,boost::spirit::ascii::space, S);


    return 0;
}

我知道我的语法不会下蹲。我现在只想从 Qi 那里得到共同的指点!为此，我发现了一些关于将智能指针与 Qi 结合使用的提示，但没有为它们提供工厂的语法。我觉得我已经很接近了，尤其是找到了 this sehe 从 Spirit General 论坛发帖。但是，我还不能把它放在一起。

编译尝试产生两个错误，如写入 ATM。

一个:

./shared_ptr_test.h:16:22: error: no matching constructor for initialization of 'SharedPtrParser<std::__1::__wrap_iter<const char *> >'
        SharedPtrParser() : SharedPtrParser(startrule)
                            ^               ~~~~~~~~~
shared_ptr_test.cpp:8:47: note: in instantiation of member function 'SharedPtrParser<std::__1::__wrap_iter<const char *> >::SharedPtrParser' requested here
        SharedPtrParser<std::string::const_iterator> C;
                                                     ^
./shared_ptr_test.h:14:8: note: candidate constructor (the implicit copy constructor) not viable: no known conversion from 'qi::rule<__wrap_iter<const char *>,
      std::shared_ptr<std::string> ()>' to 'const SharedPtrParser<std::__1::__wrap_iter<const char *> >' for 1st argument
struct SharedPtrParser :  qi::grammar<Iterator, std::shared_ptr<std::string>(), boost::spirit::ascii::space_type>
       ^
./shared_ptr_test.h:16:2: note: candidate constructor not viable: requires 0 arguments, but 1 was provided
        SharedPtrParser() : SharedPtrParser(startrule)
        ^

两个:

In file included from shared_ptr_test.cpp:1:
In file included from ./shared_ptr_test.h:4:
In file included from /usr/local/include/boost/spirit/include/qi.hpp:16:
In file included from /usr/local/include/boost/spirit/home/qi.hpp:21:
In file included from /usr/local/include/boost/spirit/home/qi/nonterminal.hpp:14:
In file included from /usr/local/include/boost/spirit/home/qi/nonterminal/rule.hpp:35:
/usr/local/include/boost/spirit/home/qi/reference.hpp:43:30: error: no matching member function for call to 'parse'
            return ref.get().parse(first, last, context, skipper, attr_);
                   ~~~~~~~~~~^~~~~
/usr/local/include/boost/spirit/home/qi/parse.hpp:164:40: note: in instantiation of function template specialization 'boost::spirit::qi::reference<const
      boost::spirit::qi::rule<std::__1::__wrap_iter<const char *>, std::__1::shared_ptr<std::__1::basic_string<char> > (),
      boost::proto::exprns_::expr<boost::proto::tagns_::tag::terminal, boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space,
      boost::spirit::char_encoding::ascii> >, 0>, boost::spirit::unused_type, boost::spirit::unused_type> >::parse<std::__1::__wrap_iter<char *>,
      boost::spirit::context<boost::fusion::cons<std::__1::shared_ptr<std::__1::basic_string<char> > &, boost::fusion::nil_>, boost::spirit::locals<mpl_::na, mpl_::na, mpl_::na,
      mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,
      boost::spirit::char_encoding::ascii> >, std::__1::shared_ptr<std::__1::basic_string<char> > >' requested here
        if (!compile<qi::domain>(expr).parse(
                                       ^
/usr/local/include/boost/spirit/home/qi/parse.hpp:197:20: note: in instantiation of function template specialization 'boost::spirit::qi::phrase_parse<std::__1::__wrap_iter<char *>,
      SharedPtrParser<std::__1::__wrap_iter<const char *> >, boost::proto::exprns_::expr<boost::proto::tagns_::tag::terminal,
      boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0>, std::__1::shared_ptr<std::__1::basic_string<char>
      > >' requested here
        return qi::phrase_parse(first, last, expr, skipper, skip_flag::postskip, attr);
                   ^
shared_ptr_test.cpp:18:11: note: in instantiation of function template specialization 'boost::spirit::qi::phrase_parse<std::__1::__wrap_iter<char *>,
      SharedPtrParser<std::__1::__wrap_iter<const char *> >, boost::proto::exprns_::expr<boost::proto::tagns_::tag::terminal,
      boost::proto::argsns_::term<boost::spirit::tag::char_code<boost::spirit::tag::space, boost::spirit::char_encoding::ascii> >, 0>, std::__1::shared_ptr<std::__1::basic_string<char>
      > >' requested here
        bool s = phrase_parse(iter, end, C,boost::spirit::ascii::space, S);
                 ^
/usr/local/include/boost/spirit/home/qi/nonterminal/rule.hpp:274:14: note: candidate function [with Context =
      boost::spirit::context<boost::fusion::cons<std::__1::shared_ptr<std::__1::basic_string<char> > &, boost::fusion::nil_>, boost::spirit::locals<mpl_::na, mpl_::na, mpl_::na,
      mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na, mpl_::na> >, Skipper = boost::spirit::qi::char_class<boost::spirit::tag::char_code<boost::spirit::tag::space,
      boost::spirit::char_encoding::ascii> >, Attribute = std::__1::shared_ptr<std::__1::basic_string<char> >] not viable: no known conversion from 'std::__1::__wrap_iter<char *>' to
      'std::__1::__wrap_iter<const char *> &' for 1st argument
        bool parse(Iterator& first, Iterator const& last
             ^
/usr/local/include/boost/spirit/home/qi/nonterminal/rule.hpp:320:14: note: candidate function template not viable: requires 6 arguments, but 5 were provided
        bool parse(Iterator& first, Iterator const& last

一点帮助？

Answer 1

我这里的问题是微不足道的。我未能为构造函数指定 ::base_type。也就是说，SharedPtrParser() : SharedPtrParser(startrule) 的行应该是 SharedPtrParser() : SharedPtrParser::base_type(startrule)。