Dynapse

Another C++ runtime reflection library.

The libdynapse consists of:

• Any: CORE functionality of the Dynapse library.
• Reflect: UTILITY that helps developers create Dynapse Any in a more simple and human-readable way.

A 'Hello World' Example

#include <dynapse/dynapse.h>
#include <iostream>

void SayHelloToWorld() {
  std::cout << "Hello, World!" << std::endl;
}

int main() {
  // compile-time register
  auto center = dynapse::MetaCenter::GetDefaultCenter();
  center->Register("SayHelloToWorld", [](auto, auto) -> dynapse::MetaPtr {
    SayHelloToWorld();
    return nullptr;
  });
  
  // runtime reflection
  center->Access("SayHelloToWorld")->CallAsFunction();
  
  return 0;
}

// console will print: Hello, World!

Complex Scenario

For those who want to reflect a CPP class, read the test.cc under Dynapse source code for now.

Another Runtime Reflection Story

I've been thinking about designing a "proper" runtime reflection library for quite a long time, those already existed ones are too complex and too boring to read the source code.

From my perspective, without knowing any stupid outer logic, a runtime reflection library should only consider:

1. How to convert all of the CPP class functions, properties, static functions, etc. to the corresbonding static function calls.

1.1 How to design those static function callbacks to request users to convert their desired value to a void pointer and convert it back.

2. How the other runtime system should interoperate with this runtime reflection library.

When all of the above design points are confirmed, a runtime reflection library firstly provide users with some static function slots a compile time that expect the users to convert a void pointer back to its original user-defined data structure to access their original CPP functions/properties, etc., then convert the resulted user-defined data structure to a void pointer and return it back. At runtime time, users should be able to dynamically call the static function slots that are pre-registered at compile time with a std::string as the function name and some void pointers as the arguments.

• For the type basic value conversion part, I take the JavaScript type design as the reference. For JavaScript, all of the types could be considered as undefined, null, number, bigint, boolean, symbol, string, function and object. For CPP, to make things simple, the runtime reflection library should provide users with an intermmediate AnyClass that could simply own or reference a nullptr, number, string, function or object typed CPP value.
• For the static function slots generation part, I defined a structure named ClassRegistry to store all of the static function callbacks when users want to construct/destroy/access property/call a function. The users will register a ClassRegistry to generate and bind static functions with a std::string name.

Finally the fake code should look like this:

ReflectionLibrary.register(className, {
  constructor: (Any args) => {
    const args = args.toArray();
    return new FooClass(arg[0], arg[1], ...);
	},
  memberProperties: {
    "bar": {
      readonly: false,
      get: (Any owner) => {
        const foo = owner.to<FooClass>();
        return Any.ref(foo.bar);
      },
    },
  },
  memberFunctions: {
    
  },
});