Division into classes (not structures)
below. I am showing an example of a contributor edited spirit that does not compile. The problem I want to solve is to parse nonstructures into classes. I know it is exactly the same except public / private. But I need to have a constructor to work with before storing the class / structure into a vector. How do I change BOOST_FUSION_ADAPT_STRUCT?
How to do it?
// STD HEADER
#include <iostream>
#include <string>
#include <complex>
// BOOST HEADER
#include <boost/config/warning_disable.hpp>
#include <boost/spirit/include/qi.hpp>
#include <boost/spirit/include/phoenix_core.hpp>
#include <boost/spirit/include/phoenix_operator.hpp>
#include <boost/spirit/include/phoenix_object.hpp>
#include <boost/fusion/include/adapt_struct.hpp>
#include <boost/fusion/include/io.hpp>
namespace client
{
namespace qi = boost::spirit::qi;
namespace ascii = boost::spirit::ascii;
class employee
{
public:
employee (
int _age
, std::string _surname
, std::string _forename
, double _salary
);
private:
int age_;
std::string surname_;
std::string forename_;
double salary_;
};
employee::employee (
int _age
, std::string _surname
, std::string _forename
, double _salary
) : age_(_age)
, surnemae_(_surename)
, forename_(_forename)
, double salary_
{
// do some important stuff
}
}
// WHAT TO DO HERE?
BOOST_FUSION_ADAPT_STRUCT(
client::employee
)
namespace client
{
template <typename Iterator>
struct employee_parser
: qi::grammar<Iterator, employee(), ascii::space_type>
{
employee_parser() : employee_parser::base_type(start)
{
using qi::int_;
using qi::lit;
using qi::double_;
using qi::lexeme;
using ascii::char_;
quoted_string %= lexeme['"' >> +(char_ - '"') >> '"'];
start %=
lit("employee")
>> '{'
>> int_ >> ','
>> quoted_string >> ','
>> quoted_string >> ','
>> double_
>> '}'
;
}
qi::rule<Iterator, std::string(), ascii::space_type> quoted_string;
qi::rule<Iterator, employee(), ascii::space_type> start;
};
}
int main()
{
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout << "\t\tAn employee parser for Spirit...\n\n";
std::cout << "/////////////////////////////////////////////////////////\n\n";
std::cout
<< "Give me an employee of the form :"
<< "employee{age, \"surname\", \"forename\", salary } \n";
std::cout << "Type [q or Q] to quit\n\n";
using boost::spirit::ascii::space;
typedef std::string::const_iterator iterator_type;
typedef client::employee_parser<iterator_type> employee_parser;
employee_parser g;
std::string str;
while (getline(std::cin, str))
{
if (str.empty() || str[0] == 'q' || str[0] == 'Q')
break;
client::employee emp;
std::string::const_iterator iter = str.begin();
std::string::const_iterator end = str.end();
bool r = phrase_parse(iter, end, g, space, emp);
if (r && iter == end)
{
std::cout << boost::fusion::tuple_open('[');
std::cout << boost::fusion::tuple_close(']');
std::cout << boost::fusion::tuple_delimiter(", ");
std::cout << "-------------------------\n";
std::cout << "Parsing succeeded\n";
std::cout << "got: " << boost::fusion::as_vector(emp) << std::endl;
std::cout << "\n-------------------------\n";
}
else
{
std::cout << "-------------------------\n";
std::cout << "Parsing failed\n";
std::cout << "-------------------------\n";
}
}
std::cout << "Bye... :-) \n\n";
return 0;
}
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You can
1. Adapt like an ADT
By adding getters / setters. Another answer refers to this as a solution: http://www.boost.org/doc/libs/release/libs/fusion/doc/html/fusion/adapted/adapt_adt.html
2. Use semantic actions:
Watch Live On Coliru
Changes:
- make the default construct constructive
-
call the constructor explicitly from the semantic action of the rule:
start = lit("employee") >> ('{' >> int_ >> ',' >> quoted_string >> ',' >> quoted_string >> ',' >> double_ >> '}' ) [ qi::_val = boost::phoenix::construct<employee>(qi::_1, qi::_2, qi::_3, qi::_4) ] ;
-
optional to overload
operator<<
so you can print the class for debugging
3. Provide customization points
See http://www.boost.org/doc/libs/1_56_0/libs/spirit/doc/html/spirit/advanced/customize/assign_to.html
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Boost.Fusion provides a macro BOOST_FUSION_ADAPT_STRUCT_ADT
that uses setter and getter functions for your use case. More information is available at: http://www.boost.org/doc/libs/1_50_0/libs/fusion/doc/html/fusion/adapted/adapt_adt.html
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