Yeah, this is a major issue of the current fusion implementation. The result_of::-metafunctions do not regard that the actual functions take const-qualified arguments only. On top of that the documentation is outdated and misleading. In your particular case result_of::join< vector<> const, vector<> const>::type j = join(v1, v2); should work fine. My C++0x port of fusion introduces non-const arguments for the algorithm functions and a new result_of::-concept which allows passing (optionally) cv and ref qualified types. -Christopher jl schrieb:

This is nearly a copy-paste from the doc (and agrees with intuition): #include #include #include void foo() { using namespace boost::fusion; vector<> v1, v2; result_of::join< vector<>, vector<> >::type j = join(v1, v2); } ...but it doesn't compile (msvc9, boost 1.40): c:\UserTemp\x54209\BoostTests\Any\main.cpp(20) : error C2440: 'initializing' : cannot convert from 'boost::fusion::result_of::join::type' to 'boost::fusion::joint_view' with [ LhSequence=const boost::fusion::vector<>, RhSequence=const boost::fusion::vector<> ] and [ Sequence1=boost::fusion::vector<>, Sequence2=boost::fusion::vector<> ] No constructor could take the source type, or constructor overload resolution was ambiguous J-L