[英]How to extract multiple structures from a string with boost::spirit
I have some complicated structures and i want to extract their data from a text using boost::spirit library (I've selected this one for efficiency purpose). 我有一些复杂的结构,我想使用boost :: spirit库从文本中提取数据(出于效率考虑,我选择了这个库)。
but i will ask my question in simpler way. 但是我会以更简单的方式问我的问题。
assume, we have two structures like these: 假设,我们有两个这样的结构:
struct person
{
std::string name;
uint8_t age;
};
and 和
struct fruit
{
std::string color;
std::double average_weight;
};
and our text that included these data is presented below: 包含这些数据的文字如下所示:
"... (jane, 23) (david, 19) (mary, 30) [yello,100] [green, 60.6] [red, 30.5]" “ ...(jane,23)(david,19)(mary,30)[yello,100] [绿色,60.6] [红色,30.5]”
now, the problem is "extracting these data in suitable format" 现在的问题是“以适当的格式提取这些数据”
for example by call handler for each struct or push_back them on vector. 例如,通过针对每个结构的调用处理程序或将它们推入vector。
any help would be greatly appreciated! 任何帮助将不胜感激!
is there any code sample about that?! 是否有任何有关此的代码示例?
call handlers for parsed structures. 解析结构的调用处理程序。
#include <string>
#define BOOST_RESULT_OF_USE_DECLTYPE
#include <boost/fusion/adapted.hpp>
#include <boost/spirit/home/qi.hpp>
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
namespace phoenix = boost::phoenix;
namespace fusion = boost::fusion;
struct person
{
std::string name;
uint8_t age;
};
BOOST_FUSION_ADAPT_STRUCT
(
person,
(std::string, name)
(uint8_t, age)
);
struct fruit
{
std::string color;
double average_weight;
};
BOOST_FUSION_ADAPT_STRUCT
(
fruit,
(std::string, color)
(double, average_weight)
);
template <typename _Iterator>
struct parser :
qi::grammar<_Iterator, void(), ascii::space_type>
{
parser() :
parser::base_type(main)
{
main =
*(
_person[ ([](const person &person_)
{
// Add handler here
}) ]
| _fruit[ ([](const fruit &fruit_)
{
// Add handler here
}) ]
);
_person = qi::lit('(') >> *(qi::char_ - ',') >> ',' >> qi::ushort_ >> ')';
_fruit = qi::lit('[') >> *(qi::char_ - ',') >> ',' >> qi::double_ >> ']';
}
qi::rule<_Iterator, void(), ascii::space_type> main;
qi::rule<_Iterator, person(), ascii::space_type> _person;
qi::rule<_Iterator, fruit(), ascii::space_type> _fruit;
};
int main()
{
typedef std::string::const_iterator iterator;
std::string input_ = "(jane, 23000) (david, 19) (mary, 30) [yello,100] [green, 60.6] [red, 30.5]";
iterator iterator_ = std::begin(input_);
bool result_ = qi::phrase_parse(iterator_, iterator(std::end(input_)), parser<iterator>(), ascii::space)
&& iterator_ == std::end(input_);
return 0;
}
PS Not all compiler can build that code because of lambdas in semantic actions. PS并非所有编译器都可以构建该代码,因为语义动作中存在lambda。 (msvs don't) In this case you have to use something else (phoenix::bind for example)
(msvs不需要)在这种情况下,您必须使用其他内容(例如phoenix :: bind)
store parsed structures in a vector 将解析的结构存储在向量中
typedef boost::variant <
person,
fruit
> variant;
template <typename _Iterator>
struct parser :
qi::grammar<_Iterator, std::vector < variant > (), ascii::space_type>
{
parser() :
parser::base_type(main)
{
main = *(_person | _fruit);
_person = qi::lit('(') >> *(qi::char_ - ',') >> ',' >> qi::ushort_ >> ')';
_fruit = qi::lit('[') >> *(qi::char_ - ',') >> ',' >> qi::double_ >> ']';
}
qi::rule<_Iterator, std::vector < variant > (), ascii::space_type> main;
qi::rule<_Iterator, person(), ascii::space_type> _person;
qi::rule<_Iterator, fruit(), ascii::space_type> _fruit;
};
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