c++ - Using mpl::vector to define boost::variant types -

i'm using library boost::variant store large number of types. number of type growing, reach limit of 20 types. in documentation seems possible define variant using mpl::vector, allows more 20 types (up 50 if i'm correct). tried replace variant definition this:

#include <boost/variant.hpp> #include <boost/mpl/vector.hpp>  typedef boost::mpl::vector<     float,     math::float2,     math::float3,     relative_point<1>,     relative_point<2>,     relative_point<3>,     std::string,     color,     group,     dictionnary,     reference,     line,     strip,     text,     font > variant_mpl_vec;  typedef boost::make_variant_over<variant_mpl_vec>::type data_type;  // old definition /*typedef boost::variant<     float,     math::float2,     math::float3,     relative_point<1>,     relative_point<2>,     relative_point<3>,     std::string,     color,     group,     dictionnary,     reference,     line,     strip,     text,     font > data_type;*/ 

i'm putting directly code. of types structures containing few data.

when compiling, got strange:

error: no matching function call ‘boost::detail::variant::make_initializer_node::apply<boost::mpl::pair< ... , lots more ... 

previous variant definition working fine, i'm surprised replacement doesn't work. i'm new mpl maybe i'm missing - can't find ! am'i doing ?

thanks in advance.

variant type definition correct, problem due generic function in program taking arbitrary variant parameter. indeed, make_variant_over<mpl::vector<t0, t1, ...>> behaves variant<t0, t1, ...> not same type: variant<over_sequence<vector<t0, t1, ...>>> (so t0 corresponds over_sequence<vector<t0, t1, ...>>.