Hi All, I am wondering if anyone knows of anything that resembles a joint_view of a pair of maps. typedef mpl::int_<1> key1_; typedef mpl::int_<2> key2_; typedef pair<key1_,int> pair1_; typedef pair<key2_,int> pair2_; typedef map<pair1_> map1_; typedef map<pair2_> map2_; map1_ m1( make_pair<key1_>(1) ); map2_ m2( make_pair<key2_>(2) ); typedef joint_view< map1_, map2_ > jv_; // not supposed to compile (?), yet it does: jv_ view(m1,m2); // but not this: // at_key<key1_>(view) // I have no choice (?) but create a new map, // although view helps a bit for initializing it: typedef map< pair1_, pair2_ > map3_; map3_ m3 = fusion::as_map(view); int n1 = fusion::at_key<key1_>(m3); BOOST_ASSERT(n1 == 1); int n2 = fusion::at_key<key2_>(m3); BOOST_ASSERT(n2 == 2);