Pass callbacks with managed parameters and return types between managed and unmanaged C++ - c++-cli

Question

I am writing a native C++ project with a managed C++ wrapper that can receive and invoke callbacks from C#. The managed side should be able to retrieve back that callback and trigger on the managed environment as well.
The signature of the said callback is:
// Native C++
typedef EvaluateResult (*NativeFunction) (std::vector<EvaluateResult> args);
// Managed C++ wrapper
delegate EvaluateResultWrapper^ ManagedFunction (List<EvaluateResultWrapper^> args);
The EvaluateResultWrapper is the managed wrapper class for the native class EvaluateResult. The conversion between the EvaluateResult is:
EvaluateResult result;
EvaluateResultWrapper^ wrapper = gcnew EvaluateResultWrapper (result);
result = EvaluateResult (*wrapper.original);
I want to implement the constructor EvaluateResultWrapper::EvaluateResultWrapper (ManagedFunction^ func) that can roughly do the following:
// NOTE: Pseudo code
void EvaluateResultWrapper::EvaluateResultWrapper (ManagedFunction^ func) {
this->func = func; // Store the func as a member to avoid GC
// original is the pointer to the EvaluateResult that this object is wrapping around
this->original = new EvaluateResult ([&func](std::vector<EvaluateResult> args) -> EvaluateResult {
List<EvaluateResultWrapper^>^ argsList; // Convert args from vector to List. Assuming it is done under the hood
EvaluateResultWrapper^ wrapper = func->Invoke (argsList); // Invoke the managed callback
return EvaluateResult (wrapper.GetOriginal ()); // Convert the managed result to the native counterpart
});
}
I know the above code will not work, but the idea I should be able to wrap the managed callback with codes that able to do conversion of both the callback arguments and return types, so that it is native friendly.
Ideally, I can also do the other way around (not important)
// NOTE: Pseudo code
ManagedFunction^ EvaluateResultWrapper::GetFunction (ManagedFunction^ func) {
// if the callback is set by the managed side, return the same callback back
if (this->func != nullptr) return this->func;
// Otherwise, the callback is a native one
NativeFunction nativeFunc = this->original->GetFunction ();
return gcnew ManagedFunction ([&nativeFunc] (List<EvaluateResultWrapper^>^ args) -> EvaluaResultWrapper {
std::vector argsList; // Convert the args from List back to vector. Assuming it is done under the hood
EvaluateResult result = nativeFunc (argsList); // Invoke the native function
return gcnew EvaluateResultWrapper (result); // Convert the native result into the managed one
});
}
I wonder whether this can be done?
A little bit of context: I am writing an external scripting system on native C++ for our games (similar to Lua scripting). The EvaluateResult is a class representing an evaluation result of any statement. It is basically a value coupled with the type. The type can be either number, boolean, string, array, object, or in this case: function callback.
The function callback can be either set within the native C++ (when the interpreter pass the user-defined function in the scripts) or a function set by the host (managed side).
The idea is the host (C# side) should be able to define and set functions into the memory (defining print() function to print into the host console for example). The callback is wrapped as an EvaluateResult class before storing into the the scripting memory.
For inspection purpose, C# side must be able to get the function callback. Therefor, the ability to get the function is nice to have (but not important, since I can always instruct the native side to execute the function for me)