Boost :: Spirit难以解析字符串

Question

我正在尝试使用Boost :: Spirit解析字符串，但是我无法使其正常工作。从今天开始，我没有使用Boost :: Spirit的经验。

该字符串由用“;”分隔的命令组成。这些命令是

“ INC someInteger”

“ BOMB第一整数第二整数”

“移动第一整数第二整数第三第三整数”

“ MSG someString”

“等待”

我设法做到了这一点：

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

using namespace boost::spirit;

int main() {    
    std::string testInput = "MOVE 1 2 43;BOMB 0 3;INC 6;MOVE 2 3 99;MOVE 1 2 6";

    typedef std::string::iterator iter;
    using boost::phoenix::ref;

    iter start = testInput.begin();

    std::vector<int> IncCommands;
    std::vector<std::pair<int, int>> BombCommands;
    std::vector<std::tuple<int, int, int>> MoveCommands;

    qi::rule<iter, std::vector<int>(), ascii::space_type> nextIncrease = ("INC " >> qi::int_);
    //qi::rule<iter, std::vector<std::pair<int, int>>(), ascii::space_type> nextBomb = ("BOMB " >> qi::int_ >> qi::int_);
    //qi::rule<iter, std::vector<int>(), ascii::space_type> nextMove = ("MOVE " >> qi::int_ >> qi::int_ >> qi::int_);

    //qi::rule<iter, std::string, ascii::space_type> nextAction = (nextMove | nextBomb | nextIncrease) % ';';

    bool match = qi::phrase_parse(
        start,
        testInput.end(),
        nextIncrease,
        ascii::space,
        IncCommands
    );

    return 0;
}

我现在遇到的问题：

1. 我不知道我怎么能提取多个整数

2. 我不知道如何将所有内容合并为适当的语法，以便将所有内容解析为多个向量。

3. 我还没有考虑过味精和等待。

Answer 1

我建议像往常一样从所需的AST开始。

Spirit可与静态多态性很好地配合使用，因此我将使用一个变体来表示命令：

namespace AST {
    namespace Cmd {
        struct Move { int x,y,z;  };
        struct Bomb { int x,y;    };
        struct Inc  { int amount; };
        struct Msg  { std::string text; };
        struct Wait {};
    }

    using Command = boost::variant<Cmd::Move, Cmd::Bomb, Cmd::Inc, Cmd::Msg, Cmd::Wait>;
    using Commands = std::vector<Command>;
}

现在，编写最简单的语法来匹配它：

template <typename It>
struct ScriptGrammar : qi::grammar<It, AST::Commands()>
{
    ScriptGrammar() : ScriptGrammar::base_type(start) {
        using namespace qi;
        start   = skip(space) [ script ];
        script  = command % ";";
        command = move|bomb|inc|msg|wait;

        move = "MOVE" >> int_ >> int_ >> int_;
        bomb = "BOMB" >> int_ >> int_;
        inc  = "INC"  >> int_;
        msg  = "MSG"  >> text;
        wait = "WAIT" >> qi::attr(AST::Cmd::Wait{});

        text  = +~char_(";");
        BOOST_SPIRIT_DEBUG_NODES((start)(script)(command)(move)(bomb)(inc)(msg)(wait)(text))
    }
  private:
    using Skipper = qi::space_type;
    qi::rule<It, AST::Commands(), Skipper>  script;
    qi::rule<It, AST::Command(), Skipper>   command;
    qi::rule<It, AST::Cmd::Move(), Skipper> move;
    qi::rule<It, AST::Cmd::Bomb(), Skipper> bomb;
    qi::rule<It, AST::Cmd::Inc(), Skipper>  inc;
    qi::rule<It, AST::Cmd::Msg(), Skipper>  msg;
    qi::rule<It, AST::Cmd::Wait(), Skipper> wait;
    // lexeme
    qi::rule<It, AST::Commands()>  start;
    qi::rule<It, std::string()>  text;
};

添加一些用于调试（融合适应和输出流传输）的胶水，我们有一个有效的示例：

Live On Coliru

#define BOOST_SPIRIT_DEBUG
#include <iostream>
#include <vector>
#include <string>
#include <iterator>
#include <iomanip>
#include <boost/spirit/include/qi.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/phoenix/phoenix.hpp>

namespace AST {
    namespace Cmd {
        struct Move { int x,y,z;  };
        struct Bomb { int x,y;    };
        struct Inc  { int amount; };
        struct Msg  { std::string text; };
        struct Wait {};
    }

    using Command = boost::variant<Cmd::Move, Cmd::Bomb, Cmd::Inc, Cmd::Msg, Cmd::Wait>;
    using Commands = std::vector<Command>;
}

BOOST_FUSION_ADAPT_STRUCT(AST::Cmd::Move, x,y,z)
BOOST_FUSION_ADAPT_STRUCT(AST::Cmd::Bomb, x,y)
BOOST_FUSION_ADAPT_STRUCT(AST::Cmd::Inc, amount)
BOOST_FUSION_ADAPT_STRUCT(AST::Cmd::Msg, text)
BOOST_FUSION_ADAPT_STRUCT(AST::Cmd::Wait)

namespace AST { namespace Cmd { // For demo/debug
    std::ostream& operator<<(std::ostream& os, Move const& cmd) { return os << "MOVE " << boost::fusion::as_vector(cmd); } 
    std::ostream& operator<<(std::ostream& os, Bomb const& cmd) { return os << "BOMB " << boost::fusion::as_vector(cmd); } 
    std::ostream& operator<<(std::ostream& os, Inc const& cmd)  { return os << "INC " << boost::fusion::as_vector(cmd);  } 
    std::ostream& operator<<(std::ostream& os, Msg const& cmd)  { return os << "MSG " << boost::fusion::as_vector(cmd);  } 
    std::ostream& operator<<(std::ostream& os, Wait const& cmd) { return os << "WAIT " << boost::fusion::as_vector(cmd); } 
} }

namespace qi = boost::spirit::qi;

template <typename It>
struct ScriptGrammar : qi::grammar<It, AST::Commands()>
{
    ScriptGrammar() : ScriptGrammar::base_type(start) {
        using namespace qi;
        start   = skip(space) [ script ];
        script  = command % ";";
        command = move|bomb|inc|msg|wait;

        move = "MOVE" >> int_ >> int_ >> int_;
        bomb = "BOMB" >> int_ >> int_;
        inc  = "INC"  >> int_;
        msg  = "MSG"  >> text;
        wait = "WAIT" >> qi::attr(AST::Cmd::Wait{});

        text  = +~char_(";");
        BOOST_SPIRIT_DEBUG_NODES((start)(script)(command)(move)(bomb)(inc)(msg)(wait)(text))
    }
  private:
    using Skipper = qi::space_type;
    qi::rule<It, AST::Commands(), Skipper>  script;
    qi::rule<It, AST::Command(), Skipper>   command;
    qi::rule<It, AST::Cmd::Move(), Skipper> move;
    qi::rule<It, AST::Cmd::Bomb(), Skipper> bomb;
    qi::rule<It, AST::Cmd::Inc(), Skipper>  inc;
    qi::rule<It, AST::Cmd::Msg(), Skipper>  msg;
    qi::rule<It, AST::Cmd::Wait(), Skipper> wait;
    // lexeme
    qi::rule<It, AST::Commands()>  start;
    qi::rule<It, std::string()>  text;
};

int main() {    
    std::string const testInput = "MOVE 1 2 43;BOMB 0 3;INC 6;MOVE 2 3 99;MSG MOVE ZIG;WAIT;MSG FOR GREAT JUSTICE!;MOVE 1 2 6";

    typedef std::string::const_iterator iter;

    iter start = testInput.begin(), end = testInput.end();

    AST::Commands script;

    bool match = qi::parse(start, testInput.end(), ScriptGrammar<iter>(), script);

    if (match) {
        std::cout << "Parsed " << script.size() << " commands\n";
        std::copy(script.begin(), script.end(), std::ostream_iterator<AST::Command>(std::cout, ";"));
    } else {
        std::cout << "Parse failed\n";
    }

    if (start != end)
        std::cout << "Remaining unparsed input: '" << std::string(start, end) << "'\n";
}

哪些打印：

Parsed 8 commands
MOVE (1 2 43);BOMB (0 3);INC (6);MOVE (2 3 99);MSG (MOVE ZIG);WAIT ();MSG (FOR GREAT JUSTICE!);MOVE (1 2 6);

以及可选的BOOST_SPIRIT_DEBUG输出：

namespace AST {
    namespace Cmd {
        struct Move { int x,y,z;  };
        struct Bomb { int x,y;    };
        struct Inc  { int amount; };
        struct Msg  { std::string text; };
        struct Wait {};
    }

    using Command = boost::variant<Cmd::Move, Cmd::Bomb, Cmd::Inc, Cmd::Msg, Cmd::Wait>;
    using Commands = std::vector<Command>;
}