Workaround to expose C++ instances in Wren with Wrenbind17

ExposeCppStateInWren.cpp

// 1. Create a struct to be able to expose some fields
struct ScriptEnv {
        std::shared_ptr<spdlog::logger> gameLog;
        Guinyote::View::VideoManager * videoManager;
        RuntimeConfig const * config;
        std::string orsAddress;
    };
// Create a C++ instance to pass the data to wren
ScriptEnv scriptEnv{
    .gameLog = logger_,
    .videoManager = i_->videoManager,
    .config = i_->config,
    .orsAddress = i_->orsAddress
    };
// Register in environment module
auto & m = vm->module("environment");
// Register ScriptEnv fields, etc.
auto & wrenEnvClass = m.klass<ScriptEnv>("ScriptEnv");
// Small nicety via C++17: template do-not-repeat-yourself
// auto template parameter for passing members to pointers 
wrenEnvClass.varReadonly<&ScriptEnv::gameLog>("log");                             
wrenEnvClass.varReadonly<&ScriptEnv::videoManager>("videoManager");
wrenEnvClass.varReadonly<&ScriptEnv::config>("config");
// Create a Wren global to expose the C++ Script env
m.append("var Env = null");
// Emit Wren code for a class that will set Env
m.append(R"--(class EnvSetter {
                                  static set(env) {
                                     Env = env
                                   }
                                  }
                             )--");
// run the module code
vm->runFromSource("environment", m.str());
// Use the set and expose the C++-side variable
vm->find("environment", "EnvSetter").func("set(_)")(&scriptEnv);