增强精神使整个比赛像弦一样

问题描述

我正在尝试使用Boost Spirit框架定义自己的语法，并且正在定义这样的匹配规则:

I'm trying to define my own grammar using boost spirit framework and I'm defining such a matching rule:

value = (
        char_('"') >>
        (*qi::lexeme[
                char_('\\') >> char_('\\') |
                char_('\\') >> char_('"')  |
                graph - char_('"') |
                char_(' ')
        ])[some_func] >>
        char_('"')
);

我想将一个动作-some_func-赋给它的一部分，并将整个匹配的字符串作为参数传递.但不幸的是我会得到 vector< boost :: variant< boost :: fusion :: vector2 ..很多东西...)...> 之类的东西.我能以某种方式将整个数据作为具有大小的char *，std :: string或什至void *来获取吗?

I'd like to assing an action - some_func - to the part of it, and pass the whole matching string as a parameter. But unfortunately I will get something like vector<boost::variant<boost::fusion::vector2 ..a lot of stuff...)...> . Can I somehow get the whole data as a char*, std::string or even void* with size?

推荐答案

查看 qi :: as_string :

演示程序的输出:

DEBUG: 'some\\"quoted\\"string.'
parse success

• Boost Spirit实施服务器应用程序上的小型单线DSL (用于这种样式)
• 使用Boost.Spirit编译简单的解析器(用于通过复制进行转义)
• 以增强的精神解析转义的字符串
• 使用boost :: spirit
解析引用的字符串>

• Boost Spirit Implement small one-line DSL on a server application (for this style)
• Compiling a simple parser with Boost.Spirit (for escaping by duplication)
• Parsing escaped strings with boost spirit
• Parse quoted strings with boost::spirit

Note however that you could simply declare the rule without a skipper and drop the lexeme alltogether: http://liveworkspace.org/code/1oEhei$0

代码(在 liveworkspace 上直播)

#include <boost/fusion/adapted.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>

namespace qi    = boost::spirit::qi;
namespace phx   = boost::phoenix;

struct some_func_t
{
    template <typename> struct result { typedef void type; };
    template <typename T>
        void operator()(T const& s) const
        {
            std::cout << "DEBUG: '" << s << "'\n";
        }
};

template <typename It, typename Skipper = qi::space_type>
    struct parser : qi::grammar<It, Skipper>
{
    parser() : parser::base_type(value)
    {
        using namespace qi;
        // using phx::bind; using phx::ref; using phx::val;

        value = (
                 char_('"') >>
                     qi::as_string
                     [
                         (*qi::lexeme[
                          char_('\\') >> char_('\\') |
                          char_('\\') >> char_('"')  |
                          graph - char_('"') |
                          char_(' ')
                          ])
                     ] [some_func(_1)] >>
                 char_('"')
            );
        BOOST_SPIRIT_DEBUG_NODE(value);
    }

  private:
    qi::rule<It, Skipper> value;
    phx::function<some_func_t> some_func;
};

bool doParse(const std::string& input)
{
    typedef std::string::const_iterator It;
    auto f(begin(input)), l(end(input));

    parser<It, qi::space_type> p;

    try
    {
        bool ok = qi::phrase_parse(f,l,p,qi::space);
        if (ok)
        {
            std::cout << "parse success\n";
        }
        else      std::cerr << "parse failed: '" << std::string(f,l) << "'\n";

        if (f!=l) std::cerr << "trailing unparsed: '" << std::string(f,l) << "'\n";
        return ok;
    } catch(const qi::expectation_failure<It>& e)
    {
        std::string frag(e.first, e.last);
        std::cerr << e.what() << "'" << frag << "'\n";
    }

    return false;
}

int main()
{
    bool ok = doParse("\"some \\\"quoted\\\" string.\"");
    return ok? 0 : 255;
}

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