boost::spirit::qi and boost::phoenix::push_back
boost::spirit::qi and boost::phoenix::push_back
基于使用boost :: spirit :: qi and boost :: phoenix :: phoenix :: push_back，以下代码正常工作 - 使用C 14。
#include <string>
#include <vector>
#include <iostream>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
namespace qi = boost::spirit::qi;
typedef std::vector<unsigned int> uint_vector_t;
std::ostream& operator<<(std::ostream& out, const uint_vector_t &data)
{
for (unsigned int i(0); i < data.size(); i++)
{
out << data[i] << 'n';
}
return out;
}
struct MyStruct
{
uint_vector_t m_aList;
uint_vector_t m_bList;
};
template<typename Iterator, typename Skipper>
struct MyParser : public boost::spirit::qi::grammar<Iterator,
MyStruct(),Skipper>
{
MyParser() :
MyParser::base_type(Parser, "Parser")
{
using boost::spirit::qi::uint_;
using boost::spirit::qi::_val;
using boost::spirit::qi::_1;
using boost::phoenix::at_c;
using boost::phoenix::push_back;
using boost::phoenix::bind;
aParser = "a=" >> uint_;
bParser = "b=" >> uint_;
Parser =
*( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)]
| bParser [push_back(bind(&MyStruct::m_bList, _val), _1)]
);
}
boost::spirit::qi::rule<Iterator, MyStruct(), Skipper> Parser;
boost::spirit::qi::rule<Iterator, unsigned int(), Skipper> aParser, bParser;
};
int main()
{
using boost::spirit::qi::phrase_parse;
std::string input("a=0nb=7531na=2na=3nb=246n");
std::string::const_iterator begin = input.begin();
std::string::const_iterator end = input.end();
MyParser<std::string::const_iterator, qi::space_type> parser;
MyStruct result;
bool succes = qi::phrase_parse(begin, end, parser,qi::space,result);
assert(succes);
std::cout << "===A===n" <<result.m_aList << "===B===n" << result.m_bList << std::endl;
return 0;
}
结果是：
===A===
0
2
3
===B===
7531
246
将另一个Qi ::符号元素添加到结构中，预计新添加的元素将被解析为水果:: Apple（0），但实际上是不确定的（出现随机）。<<<<<<<<<</p>
#include <string>
#include <vector>
#include <iostream>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
namespace qi = boost::spirit::qi;
typedef std::vector<unsigned int> uint_vector_t;
std::ostream& operator<<(std::ostream& out, const uint_vector_t &data)
{
for (unsigned int i(0); i < data.size(); i++)
{
out << data[i] << 'n';
}
return out;
}
struct MyStruct
{
enum class FRUIT
{
APPLE,
BANANA,
PEAR,
} fruit;
uint_vector_t m_aList;
uint_vector_t m_bList;
};
BOOST_FUSION_ADAPT_STRUCT
(
MyStruct,
(MyStruct::FRUIT, fruit)
(uint_vector_t, m_aList)
(uint_vector_t, m_bList)
)
template<typename Iterator, typename Skipper>
struct MyParser : public boost::spirit::qi::grammar<Iterator,
MyStruct(),Skipper>
{
MyParser() :
MyParser::base_type(Parser, "Parser")
{
using boost::spirit::qi::uint_;
using boost::spirit::qi::_val;
using boost::spirit::qi::_1;
using boost::phoenix::at_c;
using boost::phoenix::push_back;
using boost::phoenix::bind;
fruiter.add
("apple", MyStruct::FRUIT::APPLE)
("banana", MyStruct::FRUIT::BANANA)
("pear", MyStruct::FRUIT::PEAR)
;
aParser = "a=" >> uint_;
bParser = "b=" >> uint_;
Parser = fruiter >>
*( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)]
| bParser [push_back(bind(&MyStruct::m_bList, _val), _1)]
);
}
boost::spirit::qi::rule<Iterator, MyStruct(), Skipper> Parser;
boost::spirit::qi::rule<Iterator, unsigned int(), Skipper> aParser, bParser;
boost::spirit::qi::symbols<char, MyStruct::FRUIT> fruiter;
};
int main()
{
using boost::spirit::qi::phrase_parse;
std::string input("applena=0nb=7531na=2na=3nb=246n");
std::string::const_iterator begin = input.begin();
std::string::const_iterator end = input.end();
MyParser<std::string::const_iterator, qi::space_type> parser;
MyStruct result;
bool succes = qi::phrase_parse(begin, end, parser,qi::space,result);
assert(succes);
std::cout << "Fruit: " << int(result.fruit) << "n===A===n" <<result.m_aList << "===B===n" << result.m_bList << std::endl;
return 0;
}
生成的Qi ::符号元素是随机的。一个示例输出看起来像
Fruit: 29899839
===A===
0
2
3
===B===
7531
246
但是Qi ::符号元素本身也可以正常工作。
#include <string>
#include <vector>
#include <iostream>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
namespace qi = boost::spirit::qi;
struct MyStruct
{
enum class FRUIT
{
APPLE,
BANANA,
PEAR,
} fruit;
};
BOOST_FUSION_ADAPT_STRUCT
(
MyStruct,
(MyStruct::FRUIT, fruit)
)
template<typename Iterator, typename Skipper>
struct MyParser : public boost::spirit::qi::grammar<Iterator,
MyStruct(),Skipper>
{
MyParser() :
MyParser::base_type(Parser, "Parser")
{
using boost::spirit::qi::uint_;
using boost::spirit::qi::_val;
using boost::spirit::qi::_1;
using boost::phoenix::at_c;
using boost::phoenix::push_back;
using boost::phoenix::bind;
fruiter.add
("apple", MyStruct::FRUIT::APPLE)
("banana", MyStruct::FRUIT::BANANA)
("pear", MyStruct::FRUIT::PEAR)
;
Parser = fruiter;
}
boost::spirit::qi::rule<Iterator, MyStruct(), Skipper> Parser;
boost::spirit::qi::symbols<char, MyStruct::FRUIT> fruiter;
};
int main()
{
using boost::spirit::qi::phrase_parse;
std::string input("apple");
std::string::const_iterator begin = input.begin();
std::string::const_iterator end = input.end();
MyParser<std::string::const_iterator, qi::space_type> parser;
MyStruct result;
bool succes = qi::phrase_parse(begin, end, parser,qi::space,result);
assert(succes);
std::cout << "Fruit: " << int(result.fruit) << "n";
return 0;
}
结果看起来像：
Fruit: 0
我做错了什么？预先感谢。
语义动作抑制属性的自动传播。这显然也是该程序的第一个版本没有针对MyResult结构进行改编的原因。
所以
-
坚持语义动作¹（删除适应性结构）
活在coliru
Parser = fruiter[bind(&MyStruct::fruit, _val) = _1] >> *( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)] | bParser [push_back(bind(&MyStruct::m_bList, _val), _1)] ); -
或使用
operator%=重新启用自动属性传播语义。// NOTE c++11+ syntax: BOOST_FUSION_ADAPT_STRUCT(MyStruct, fruit, m_aList, m_bList) Parser %= fruiter >> *( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)] | bParser [push_back(bind(&MyStruct::m_bList, _val), _1)] );请注意，如果
fruit不是第一个改编的序列元素，则很容易分解。实际上，只适应预期元素要干净很多：BOOST_FUSION_ADAPT_STRUCT(MyStruct, fruit)甚至清洁器以明确说明哪些属性有望传播：
Parser %= fruiter >> omit [ *( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)] | bParser [push_back(bind(&MyStruct::m_bList, _val), _1)] ) ];活在Coliru
完整列表
活在coliru
#include <iostream>
#include <string>
#include <vector>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/spirit/include/phoenix.hpp>
#include <boost/spirit/include/qi.hpp>
namespace qi = boost::spirit::qi;
typedef std::vector<unsigned int> Uints;
namespace std {
std::ostream& operator<<(std::ostream& out, const Uints &data) {
for (auto i : data) out << i << " ";
return out << "n";
}
}
struct MyStruct {
enum class FRUIT {
APPLE,
BANANA,
PEAR,
} fruit;
friend std::ostream& operator<<(std::ostream& out, FRUIT f) {
switch(f) {
case FRUIT::APPLE: return out << "APPLE";
case FRUIT::BANANA: return out << "BANANA";
case FRUIT::PEAR: return out << "PEAR";
}
return out << "FRUIT[?" << static_cast<int>(f) << "]";
}
Uints m_aList;
Uints m_bList;
};
BOOST_FUSION_ADAPT_STRUCT(MyStruct, fruit)
template <typename Iterator, typename Skipper>
struct MyParser : public qi::grammar<Iterator, MyStruct(), Skipper> {
MyParser() : MyParser::base_type(Parser, "Parser") {
using namespace qi;
using boost::phoenix::push_back;
using boost::phoenix::bind;
fruiter.add("apple", MyStruct::FRUIT::APPLE)("banana", MyStruct::FRUIT::BANANA)("pear", MyStruct::FRUIT::PEAR);
aParser = "a=" >> uint_;
bParser = "b=" >> uint_;
Parser %= fruiter >>
omit [
*( aParser [push_back(bind(&MyStruct::m_aList, _val), _1)]
| bParser [push_back(bind(&MyStruct::m_bList, _val), _1)]
)
];
}
private:
qi::rule<Iterator, MyStruct(), Skipper> Parser;
qi::rule<Iterator, unsigned int(), Skipper> aParser, bParser;
qi::symbols<char, MyStruct::FRUIT> fruiter;
};
int main() {
std::string input("bananana=0nb=7531na=2na=3nb=246n");
using It = std::string::const_iterator;
It begin = input.begin(), end = input.end();
MyParser<It, qi::space_type> parser;
MyStruct result;
bool succes = qi::phrase_parse(begin, end, parser, qi::space, result);
if (succes) {
std::cout
<< "Fruit: " << result.fruit
<< "n===A===n" <<result.m_aList << "===B===n" << result.m_bList << std::endl;
} else {
std::cout << "Parse failedn";
}
}
打印
Fruit: BANANA
===A===
0 2 3
===B===
7531 246
Å重复我的口头禅：增强精神："语义动作是邪恶的"？
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