BoolTranslator for boost::property_tree::ptree

gistfile1.cpp

#include <boost/algorithm/string/predicate.hpp>

struct BoolTranslator
{
  typedef std::string internal_type;
  typedef bool external_type;

  // Converts a string to bool
  boost::optional<external_type> get_value(const internal_type& str)
  {
    if (!str.empty()) {
      if (boost::algorithm::iequals(str, "true") || boost::algorithm::iequals(str, "yes") || boost::algorithm::iequals(str, "enabled") || str == "1")
        return boost::optional<external_type>(true);
      else
        return boost::optional<external_type>(false);
    }
    else
      return boost::optional<external_type>(boost::none);
  }

  // Converts a bool to string
  boost::optional<internal_type> put_value(const external_type& b)
  {
    return boost::optional<internal_type>(b ? "true" : "false");
  }
};

// Specialize translator_between so that it uses our custom translator for
// bool value types. Specialization must be in boost::property_tree namespace.
namespace boost {
  namespace property_tree {
    template<typename Ch, typename Traits, typename Alloc> 
    struct translator_between<std::basic_string< Ch, Traits, Alloc >, bool>
    {
      typedef BoolTranslator type;
    };
  }
}

// taken from http://stackoverflow.com/questions/9745716/change-how-boostproperty-tree-reads-translates-strings-to-bool