Is there a good way to expose sf::Event to Lua with Luabridge?
Since this question has received zero comments or answers, I've decided not to rule out other libraries. So, if there is a C++ library that supports enums, I will accept it
The Thor library, an SFML extension, supports conversions between SFML key types and strings. This would help you serialize enumerators and pass them as strings to Lua -- and back if you need.