cpp-reflection/include/reflection/forward.h

//
//  forward.h
//  reflection
//
//  Created by Sam Jaffe on 7/3/22.
//  Copyright © 2022 Sam Jaffe. All rights reserved.
//

#pragma once

#include <functional>
#include <map>
#include <string>
#include <type_traits>
#include <typeindex>
#include <unordered_map>

namespace reflection {
class Context;
class ContextScope;
class Object;
class Scope;
template <typename Obj, typename = void> class Reflection;
template <typename T> class Proxy;
template <typename T> class TypeCast;

template <typename Func> using Cache = std::map<std::string_view, Func>;
template <typename T> using TypeMap = std::unordered_map<std::type_index, T>;
template <typename Obj>
using Accessor = std::function<Object(Obj &, std::string)>;
template <typename Obj>
using Getter = std::function<Object(Obj const &, std::string)>;

template <typename T> constexpr std::string_view Name = "";
}

#define reflect(object) reflection::Object(object, #object)

#define INSTANTIATE_REFLECTION_IMPL(T, name, ...)                              \
  template <> constexpr std::string_view Name<T> = name;                       \
  template Cache<Accessor<T>> Reflection<T>::members_;                         \
  template Cache<Getter<T>> Reflection<T>::const_members_

#define INSTANTIATE_REFLECTION(T, ...)                                         \
  INSTANTIATE_REFLECTION_IMPL(T, ##__VA_ARGS__, #T)

#define INSTANTIATE_REFLECTION_TYPECAST_IMPL(T, name, ...)                     \
  template <> constexpr std::string_view Name<T> = name;                       \
  template TypeMap<std::function<T(Object const &)>> TypeCast<T>::get_;        \
  template TypeMap<std::function<void(Object &, T const &)>> TypeCast<T>::set_

#define INSTANTIATE_REFLECTION_TYPECAST(T, ...)                                \
  INSTANTIATE_REFLECTION_TYPECAST_IMPL(T, ##__VA_ARGS__, #T)

#if !defined(CONCAT)
#define CONCAT_IMPL(A, B) A##B
#define CONCAT(A, B) CONCAT_IMPL(A, B)
#endif

#define REFLECTION(T)                                                          \
  bool const CONCAT(reflection_, __LINE__) = ::reflection::Reflection<T>()

#define REFLECTION_TYPE_CAST(T)                                                \
  bool const CONCAT(type_cast_, __LINE__) = ::reflection::TypeCast<T>()

#define IS_SCOPE_CONTAINER(C) \
    std::is_constructible_v<std::string_view, \
                            decltype(*std::begin(std::declval<C>()))>