I was using 5.8.1 as follows:
auto chai = std::unique_ptr<chaiscript::ChaiScript>(new chaiscript::ChaiScript(chaiscript::Std_Lib::library()));
auto scriptFileName = cocos2d::FileUtils::getInstance()->fullPathForFilename("World1.chai");
// Get the Chaiscript Engine
auto chaiscript = CocosChai::create_chaiscript();
// Get a reference to the function in the script
auto setupLevel_script = chaiscript->eval<std::function<void (int, WorldLayer*)>>("setUpLevel");
// Call the function
Now I am trying to get this working with v 6 and I get build error "no matching constructor".
I have seen (and tried to use) a previous answer to a similar question - but my C++ skills just aren't up to it!
I'd appreciate any help you may be able to offer