What's the right way to create a templated class on the C++ side with Cxx? I have an LCCollection <http://lcio.desy.de/v02-07/doc/doxygen_api/html/classEVENT_1_1LCCollection.html>, and I would like to create a CellIDDecoder <http://lcio.desy.de/v02-07/doc/doxygen_api/html/classUTIL_1_1CellIDDecoder.html>, which needs a template argument.
A simple cxx"""UTIL::CellIDDecoder<SimCalorimeterHit>($(collection.coll)) x; std::cout << x << std::endl; results in ERROR: LoadError: Creating LLVM constants for type `T` not implemented yet in llvmconst(::Any) at /home/stru821/.julia/v0.5/Cxx/src/cxxstr.jl:22 in ArgCleanup(::Cxx.ClangCompiler, ::Cxx.CppPtr{Cxx.CxxQualType{Cxx. CppBaseType{Symbol("EVENT::LCCollection")},(false,false,false)},(false,false ,false)}, ::Cxx.CppPtr{Cxx.CxxQualType{Cxx.CppBaseType{Symbol( "clang::VarDecl")},(false,false,false)},(false,false,false)}) at /home/ stru821/.julia/v0.5/Cxx/src/cxxstr.jl:192 in macro expansion at /home/stru821/.julia/v0.5/Cxx/src/cxxstr.jl:634 [ inlined] in getCellIDDecoder(::LCIO.LCCollection{Cxx.CppPtr{Cxx.CxxQualType{Cxx. CppBaseType{Symbol("EVENT::SimCalorimeterHit")},(false,false,false)},(false, false,false)}}) at /home/stru821/.julia/v0.5/LCIO/src/CaloHit.jl:29 in testReader(::String) at /home/stru821/.julia/v0.5/LCIO/examples/ testLCIOCxx.jl:14 in include_from_node1(::String) at ./loading.jl:426 in process_options(::Base.JLOptions) at ./client.jl:266 in _start() at ./client.jl:322 while loading /home/stru821/.julia/v0.5/LCIO/examples/testLCIOCxx.jl, in expression starting on line 22 I have also tried to return the result of icxx"""UTIL::CellIDDecoder<SimCalorimeterHit>($(collection.coll)); But that replies with an even stranger message: :2:45: error: no matching constructor for initialization of 'UTIL::CellIDDecoder<SimCalorimeterHit>' UTIL::CellIDDecoder < SimCalorimeterHit > ( __juliavar1 ) ; ^ /scratch/software/lcio-test/include/UTIL/CellIDDecoder.h:36:3: note: candidate constructor not viable: requires single argument 'encoder_str', but no arguments were provided CellIDDecoder( const std::string& encoder_str ) : _oldHit(0) { ^ /scratch/software/lcio-test/include/UTIL/CellIDDecoder.h:47:5: note: candidate constructor not viable: requires single argument 'col', but no arguments were provided CellIDDecoder( const EVENT::LCCollection* col ) : _oldHit(0) { ^ The code clearly has a constructor argument, so I don't understand why the compiler things it doesn't... If somebody knows how to construct such a templated class, please share. Many thanks.