cpp-bind-any-methods

The way you can bind any methods(even class's member functions) to map and call it dynamically.

Usage

Code

#include "my_function_map.h"
std::string add_str(std::string i, std::string j) {
	return i + " " +  j;
}

int main() {
  MyFunctionMap myFunctionMap;
  myFunctionMap.bindFunction("add_str", &add_str);
  std::string value = std::any_cast<std::string>(myFunctionMap.getFunction("add_str")->call({ std::string("Hello"), std::string("World") }));
  std::cout << value << "\n";
}

Console Output

Hello World

How does It works?

1. The Function class does not have any template factors.
2. Only CallableFunction and CallableClassFunction, which inherit the Function class, have template factors.
3. The MyFunctionMap class has a pointer of the Function class as information of the map.
4. The call function of the Function class is declared as a virtual function.
5. In the call function, the internal binded function is called through the C++'s variadic template and std::apply.

Where do I use it?

You can use this technique to your own dynamic language interpreter.

Warning

• Only C++ 17+ compiler can compile this source.
• When you call Function::call(const std::vector<std::any>& args) function, You should pass explicit value. If type of given parameters are not the same with info of binded function, It will throw std::bad_any_cast.
• The binded function must uses decltype(nullptr) instead of void at return type('Cause we can't covert void type into std::any) and return nullptr.