Boost read_json e C ++ 11
Estou tentando analisar JSON usando o analisador property_tree do Boost e do código C ++ 11 (meu sistema é o Debian Wheezy com o gcc 4.7.2 e o Boost 1.49). Eu tentei o seguinte código baseado emSerializando e desserializando json com boost:
#include <map>
#include <sstream>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/json_parser.hpp>
using boost::property_tree::ptree; using boost::property_tree::read_json; using boost::property_tree::write_json;
void example() {
// Write json.
ptree pt;
pt.put ("foo", "bar");
std::ostringstream buf;
write_json (buf, pt, false);
std::string json = buf.str(); // {"foo":"bar"}
// Read json.
ptree pt2;
std::istringstream is (json);
read_json (is, pt2);
std::string foo = pt2.get<std::string> ("foo");
}
Se eu compilar isso comg++ -std=c++03 -c' everything is fine. However, I also want to use C++11 features (which the code in the linked thread actually does!). But with
g ++ -std = c ++ 11 -c 'Eu recebo erros de compilação:
In file included from /usr/include/boost/property_tree/json_parser.hpp:14:0,
from test.cpp:4:
/usr/include/boost/property_tree/detail/json_parser_read.hpp: In instantiation of ‘void boost::property_tree::json_parser::context<Ptree>::a_literal_val::operator() (boost::property_tree::json_parser::context<Ptree>::It, boost::property_tree::json_parser::context<Ptree>::It) const [with Ptree = boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> >; boost::property_tree::json_parser::context<Ptree>::It = __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >]’:
/usr/include/boost/spirit/home/classic/core/scanner/scanner.hpp:148:13: required from ‘static void boost::spirit::classic::attributed_action_policy<boost::spirit::classic::nil_t>::call(const ActorT&, boost::spirit::classic::nil_t, const IteratorT&, const IteratorT&) [with ActorT = boost::property_tree::json_parser::context<boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> > >::a_literal_val; IteratorT = __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >]’
/usr/include/boost/spirit/home/classic/core/scanner/scanner.hpp:163:13: required from ‘void boost::spirit::classic::action_policy::do_action(const ActorT&, AttrT&, const IteratorT&, const IteratorT&) const [with ActorT = boost::property_tree::json_parser::context<boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> > >::a_literal_val; AttrT = boost::spirit::classic::nil_t; IteratorT = __gnu_cxx::__normal_iterator<char*, std::vector<char, std::allocator<char> > >]’
...
test.cpp:20:1: required from here
/usr/include/boost/property_tree/detail/json_parser_read.hpp:105:17: error: no matching function for call to ‘boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> >::push_back(std::pair<std::basic_string<char>, std::basic_string<char> >)’
/usr/include/boost/property_tree/detail/json_parser_read.hpp:105:17: note: candidate is:
In file included from /usr/include/boost/property_tree/ptree.hpp:516:0,
from test.cpp:3:
/usr/include/boost/property_tree/detail/ptree_implementation.hpp:362:9: note: boost::property_tree::basic_ptree<Key, Data, KeyCompare>::iterator boost::property_tree::basic_ptree<Key, Data, KeyCompare>::push_back(const value_type&) [with Key = std::basic_string<char>; Data = std::basic_string<char>; KeyCompare = std::less<std::basic_string<char> >; boost::property_tree::basic_ptree<Key, Data, KeyCompare>::value_type = std::pair<const std::basic_string<char>, boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> > >]
/usr/include/boost/property_tree/detail/ptree_implementation.hpp:362:9: note: no known conversion for argument 1 from ‘std::pair<std::basic_string<char>, std::basic_string<char> >’ to ‘const value_type& {aka const std::pair<const std::basic_string<char>, boost::property_tree::basic_ptree<std::basic_string<char>, std::basic_string<char> > >&}’
Como posso usar o read_json do Boost com o C ++ 11? Preciso de uma nova versão do Boost para isso (ou seja, instalar manualmente a partir da fonte, em vez de usar o empacotado do Wheezy)? Há algo errado no meu código? Ou isso simplesmente não é possível?