一个人如何创建规则以读取3组中的整数,即...

1 2 3                   OK, 1 set of 3 ints
1 2 3 4 5 6             OK, 2 sets of 3 ints
1 2 3 4 5               ERROR, 1 set of 3 ints, 1 short for 2nd
1 2 3 4 5 6 7 8 9       OK, 3 sets of 3 ints
1 2 3 4 5 6 7 8 9 10    ERROR, 3 sets of 3 ints, 1 short for 4th

我在融合Adapt结构上遇到问题(如何使args数量可变)...
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, n1, n2, n3, n4, n5, n6)

而且不确定为什么这个规则行不通。
... = *(int_ >> int_ >> int_);

这是我的尝试...
http://coliru.stacked-crooked.com/a/cb10e8096c95fc55
//#define BOOST_SPIRIT_X3_DEBUG
#include <iostream>
#include <boost/spirit/home/x3.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>

namespace client {
    namespace ast {

        struct number {
            int n1, n2, n3, n4, n5, n6;
        };

        struct comment {
            std::string text;
            bool dummy;
        };

        struct input {
            std::vector<comment> comments;
            std::vector<number> numbers;
        };
    }
}

BOOST_FUSION_ADAPT_STRUCT(client::ast::comment, text, dummy)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, n1, n2, n3) // , n4, n5, n6) error
BOOST_FUSION_ADAPT_STRUCT(client::ast::input, comments, numbers)

namespace client {
    namespace parser {

        namespace x3 = boost::spirit::x3;
        using namespace x3;

        typedef std::string::const_iterator It;

        using namespace x3;

        auto const comment = rule<struct _c, ast::comment> {"comment"} = lexeme[*(char_ - eol)] >> attr(false);
        auto const number  = rule<struct _n, ast::number> {"number"}   = int_ >> int_ >> int_;
        // auto const number  = rule<struct _n, ast::number> {"number"}   = *(int_ >> int_ >> int_); error

        auto lines = [](auto p) { return *(p >> eol); };

        auto const input =
            repeat(1)[comment] >> eol >>
            lines(number);
    }
}

int main() {
    namespace x3 = boost::spirit::x3;

    std::string const iss("any char string here\n1 2 3\n1 2 3 4 5 6");

    auto iter = iss.begin(), eof = iss.end();

    client::ast::input types;

    bool ok = phrase_parse(iter, eof, client::parser::input, x3::blank, types);

    if (iter != eof) {
        std::cout << "Remaining unparsed: '" << std::string(iter, eof) << "'\n";
    }
    std::cout << "Parsed: " << (100.0 * std::distance(iss.begin(), iter) / iss.size()) << "%\n";
    std::cout << "ok = " << ok << std::endl;

    for (auto& item : types.comments) { std::cout << "comment: " << boost::fusion::as_deque(item) << "\n"; }
    for (auto& item : types.numbers)  { std::cout << "number:  " << boost::fusion::as_deque(item) << "\n"; }
}

列印
Parsed: 71.0526%
ok = 1
comment: (any char string here 0)
number:  (1 2 3)

最佳答案

运算符Kleene-star合成为容器属性(文档显示:vector<T>)

您的结构number不是容器属性。所以。

另外,我还不清楚您要实现什么目标。您的结构应该是6个整数,但您想解析3个组?这些组是什么意思?我可能会做:

struct number {
    struct group { int n1, n2, n3; };
    std::vector<group> groups;
};

BOOST_FUSION_ADAPT_STRUCT(client::ast::number::group, n1, n2, n3)
BOOST_FUSION_ADAPT_STRUCT(client::ast::number, groups)

然后,这与解析器表达式兼容
 *(int_ >> int_ >> int_)

现场演示

两个注意事项:
  • 再次需要假人服装(考虑using number = std::vector<number_group>;)
  • 输入的末尾缺少\n(考虑eol | eoi)

  • Live On Coliru
    //#define BOOST_SPIRIT_X3_DEBUG
    #include <iostream>
    #include <boost/spirit/home/x3.hpp>
    #include <boost/fusion/include/adapt_struct.hpp>
    #include <boost/fusion/include/io.hpp>
    
    namespace client {
        namespace ast {
    
            struct number {
                struct group { int n1, n2, n3; };
                std::vector<group> groups;
                bool dummy;
            };
    
            struct comment {
                std::string text;
                bool dummy;
            };
    
            struct input {
                std::vector<comment> comments;
                std::vector<number> numbers;
            };
        }
    }
    
    BOOST_FUSION_ADAPT_STRUCT(client::ast::comment, text, dummy)
    BOOST_FUSION_ADAPT_STRUCT(client::ast::number::group, n1, n2, n3)
    BOOST_FUSION_ADAPT_STRUCT(client::ast::number, groups, dummy)
    BOOST_FUSION_ADAPT_STRUCT(client::ast::input, comments, numbers)
    
    namespace client {
        namespace parser {
    
            namespace x3 = boost::spirit::x3;
            using namespace x3;
    
            typedef std::string::const_iterator It;
    
            using namespace x3;
    
            auto const comment = rule<struct _c, ast::comment> {"comment"} = lexeme[*(char_ - eol)] >> attr(false);
            auto const number  = rule<struct _n, ast::number> {"number"}   = *(int_ >> int_ >> int_) >> attr(false);
    
            auto lines = [](auto p) { return *(p >> eol); };
    
            auto const input =
                repeat(1)[comment] >> eol >>
                lines(number);
        }
    }
    
    int main() {
        namespace x3 = boost::spirit::x3;
    
        std::string const iss("any char string here\n1 2 3\n1 2 3 4 5 6\n");
    
        auto iter = iss.begin(), eof = iss.end();
    
        client::ast::input types;
    
        bool ok = phrase_parse(iter, eof, client::parser::input, x3::blank, types);
    
        if (iter != eof) {
            std::cout << "Remaining unparsed: '" << std::string(iter, eof) << "'\n";
        }
        std::cout << "Parsed: " << (100.0 * std::distance(iss.begin(), iter) / iss.size()) << "%\n";
        std::cout << "ok = " << ok << std::endl;
    
        for (auto &item : types.comments) {
            std::cout << "comment: " << boost::fusion::as_deque(item) << "\n";
        }
        for (auto& item : types.numbers) {
            std::cout << "number:  ";
            for (auto& g : item.groups)
                std::cout << boost::fusion::as_deque(g) << " ";
            std::cout << "\n";
        }
    }
    

    版画
    Parsed: 100%
    ok = 1
    comment: (any char string here 0)
    number:  (1 2 3)
    number:  (1 2 3) (4 5 6)
    

    10-05 22:42
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