Thomas saidParametrization seems to be the right way to do it! Thanks for the great post - and the valuable tips..
Glad that it was useful to you.
I'm not sure if this will sway you on switching to Boost.Variant, but here's what the traversals might look like:
namespace {
json_string string_to_json( const wstring &s ) {
return L"\"" + replaceAll( s, L"\"", L"\\\"" ) + L"\"";
}
struct atom_to_json : public boost::static_visitor< json_string > {
json_string operator()( t_null ) const {
return L"null";
}
json_string operator()( const wstring &s ) const {
return string_to_json( s );
}
template< typename T >
json_string operator()( T i ) const {
return FSLib::coerce< wstring >( i );
}
};
struct to_json : public boost::static_visitor< json_string > {
json_string operator()( const Json::atom_t &t ) const {
return boost::apply_visitor( ::atom_to_json(), t );
}
json_string operator()( const Json::array_t &t ) const {
std::wostringstream s;
for ( Json::array_t::const_iterator i( t.begin() ); i != t.end(); ++i )
s << ( i == t.begin() ? wstring() : L"," ) << toJson( **i );
return L"[" + s.str() + L"]";
}
json_string operator()( const Json::object_t &t ) const {
std::wostringstream s;
for ( Json::object_t::const_iterator i( t.begin() ); i != t.end(); ++i )
s << ( i == t.begin() ? wstring() : L"," ) << string_to_json( i->first ) << L":" << toJson( *i->second );
return L"{" + s.str() + L"}";
}
};
}
json_string FSLib::toJson( const Json &json ) {
return boost::apply_visitor( ::to_json(), json );
}The string mangling isn't quite up to production quality — it probably ought to do something explicit about control characters and throw for those that aren't supported. I think the call to coerce can be replaced with Boost's lexical cast.
I think the big advantage here is that there are no type holes. You are forced to address each type within the variants or it won't compile and you also know you won't get any surprises at run time.
It does however imply a widening of scope of TinyJSON to a full JSON library rather than just parsing. Maybe that's Ok for version 2 though? :)
