diff --git a/include/pybind11/embed.h b/include/pybind11/embed.h
new file mode 100644
index 00000000..be8234ee
--- /dev/null
+++ b/include/pybind11/embed.h
@@ -0,0 +1,2 @@
+#pragma once
+#include "pybind11.h"
diff --git a/include/pybind11/functional.h b/include/pybind11/functional.h
new file mode 100644
index 00000000..bdfc5342
--- /dev/null
+++ b/include/pybind11/functional.h
@@ -0,0 +1,2 @@
+#pragma once
+#include "pybind11.h"
\ No newline at end of file
diff --git a/include/pybind11/internal/accessor.h b/include/pybind11/internal/accessor.h
new file mode 100644
index 00000000..6d100557
--- /dev/null
+++ b/include/pybind11/internal/accessor.h
@@ -0,0 +1,173 @@
+#pragma once
+#include "builtins.h"
+
+namespace pybind11 {
+
+// implement iterator methods for interface
+template <typename Derived>
+inline iterator interface<Derived>::begin() const {
+    return handle(vm->py_iter(this->ptr()));
+}
+
+template <typename Derived>
+inline iterator interface<Derived>::end() const {
+    return iterator::sentinel();
+}
+
+template <typename Derived>
+inline str interface<Derived>::package() const {
+    return handle(this->attr(pkpy::__package__));
+}
+
+template <typename Derived>
+inline str interface<Derived>::name() const {
+    return handle(this->attr(pkpy::__name__));
+}
+
+template <typename Derived>
+inline str interface<Derived>::repr() const {
+    return handle(str(vm->py_repr(this->ptr())));
+}
+
+template <typename policy>
+class accessor : public interface<accessor<policy>> {
+
+    using key_type = typename policy::key_type;
+
+    handle m_obj;
+    mutable handle m_value;
+    key_type m_key;
+
+    friend interface<handle>;
+    friend interface<accessor<policy>>;
+    friend tuple;
+    friend list;
+    friend dict;
+
+    accessor(const handle& obj, key_type key) : m_obj(obj), m_value(), m_key(key) {}
+
+public:
+    pkpy::PyVar ptr() const {
+        if(!m_value) { m_value = policy::get(m_obj, m_key); }
+        return m_value.ptr();
+    }
+
+    template <typename Value>
+    accessor& operator= (Value&& value) && {
+        policy::set(m_obj, m_key, std::forward<Value>(value));
+        return *this;
+    }
+
+    template <typename Value>
+    accessor& operator= (Value&& value) & {
+        m_value = std::forward<Value>(value);
+        return *this;
+    }
+
+    template <typename T>
+    T cast() const {
+        return operator handle ().template cast<T>();
+    }
+
+    operator handle () const { return ptr(); }
+};
+
+namespace policy {
+struct attr {
+    using key_type = pkpy::StrName;
+
+    static handle get(const handle& obj, pkpy::StrName key) { return vm->getattr(obj.ptr(), key); }
+
+    static void set(const handle& obj, pkpy::StrName key, const handle& value) {
+        vm->setattr(obj.ptr(), key, value.ptr());
+    }
+};
+
+struct item {
+    using key_type = handle;
+
+    static handle get(const handle& obj, const handle& key) {
+        return vm->call(vm->py_op("getitem"), obj.ptr(), key.ptr());
+    }
+
+    static void set(const handle& obj, const handle& key, const handle& value) {
+        vm->call(vm->py_op("setitem"), obj.ptr(), key.ptr(), value.ptr());
+    }
+};
+
+struct tuple {
+    using key_type = int;
+
+    static handle get(const handle& obj, int key) { return obj._as<pkpy::Tuple>()[key]; }
+
+    static void set(const handle& obj, size_t key, const handle& value) { obj._as<pkpy::Tuple>()[key] = value.ptr(); }
+};
+
+struct list {
+    using key_type = int;
+
+    static handle get(const handle& obj, size_t key) { return obj._as<pkpy::List>()[key]; }
+
+    static void set(const handle& obj, size_t key, const handle& value) { obj._as<pkpy::List>()[key] = value.ptr(); }
+};
+
+struct dict {
+    using key_type = handle;
+
+    static handle get(const handle& obj, const handle& key) { return obj.cast<pybind11::dict>().getitem(key); }
+
+    static void set(const handle& obj, const handle& key, const handle& value) {
+        obj.cast<pybind11::dict>().setitem(key, value);
+    }
+};
+
+}  // namespace policy
+
+// implement other methods of interface
+
+template <typename Derived>
+inline attr_accessor interface<Derived>::attr(pkpy::StrName key) const {
+    return attr_accessor(this->ptr(), key);
+}
+
+template <typename Derived>
+inline attr_accessor interface<Derived>::attr(const char* key) const {
+    return attr_accessor(this->ptr(), pkpy::StrName(key));
+}
+
+template <typename Derived>
+inline attr_accessor interface<Derived>::attr(const handle& key) const {
+    return attr_accessor(this->ptr(), pkpy::StrName(key._as<pkpy::Str>()));
+}
+
+template <typename Derived>
+inline attr_accessor interface<Derived>::doc() const {
+    return attr_accessor(this->ptr(), pkpy::StrName("__doc__"));
+}
+
+template <typename Derived>
+inline item_accessor interface<Derived>::operator[] (int index) const {
+    return item_accessor(this->ptr(), int_(index));
+}
+
+template <typename Derived>
+inline item_accessor interface<Derived>::operator[] (const char* key) const {
+    return item_accessor(this->ptr(), str(key));
+}
+
+template <typename Derived>
+inline item_accessor interface<Derived>::operator[] (const handle& key) const {
+    return item_accessor(this->ptr(), key);
+}
+
+inline tuple_accessor tuple::operator[] (int i) const { return tuple_accessor(this->ptr(), i); }
+
+inline list_accessor list::operator[] (int i) const { return list_accessor(this->ptr(), i); }
+
+inline dict_accessor dict::operator[] (int index) const { return dict_accessor(this->ptr(), int_(index)); }
+
+inline dict_accessor dict::operator[] (std::string_view key) const { return dict_accessor(this->ptr(), str(key)); }
+
+inline dict_accessor dict::operator[] (const handle& key) const { return dict_accessor(this->ptr(), key); }
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/builtins.h b/include/pybind11/internal/builtins.h
new file mode 100644
index 00000000..aa616ca9
--- /dev/null
+++ b/include/pybind11/internal/builtins.h
@@ -0,0 +1,222 @@
+#pragma once
+#include "types.h"
+#include "type_traits.h"
+
+namespace pybind11 {
+
+inline object eval(std::string_view code, const handle& global = none{}, handle local = none{}) {
+    return vm->py_eval(code, global.ptr(), local.ptr());
+}
+
+inline void exec(std::string_view code, const handle& global = none{}, handle local = none{}) {
+    vm->py_exec(code, global.ptr(), local.ptr());
+}
+
+/// globas() in pkpy is immutable, your changes will not be reflected in the Python interpreter
+inline dict globals() {
+    auto& proxy = eval("globals()")._as<pkpy::MappingProxy>().attr();
+    dict result;
+#if PK_VERSION_MAJOR == 2
+    proxy.apply(
+        [](pkpy::StrName key, pkpy::PyVar value, void* data) {
+            auto& dict = static_cast<pybind11::dict*>(data)->_as<pkpy::Dict>();
+            auto key_ = pybind11::str(key.sv()).ptr();
+            dict.set(vm, key_, value);
+        },
+        &result);
+#else
+    proxy.apply([&](pkpy::StrName key, pkpy::PyVar value) {
+        result.setitem(str(key.sv()), value);
+    });
+#endif
+    return result;
+}
+
+// wrapper for builtin functions in Python
+inline bool hasattr(const handle& obj, const handle& name) {
+    return vm->getattr(obj.ptr(), name._as<pkpy::Str>(), false) != nullptr;
+}
+
+inline bool hasattr(const handle& obj, const char* name) { return vm->getattr(obj.ptr(), name, false) != nullptr; }
+
+inline void delattr(const handle& obj, const handle& name) { vm->delattr(obj.ptr(), name._as<pkpy::Str>()); }
+
+inline void delattr(const handle& obj, const char* name) { vm->delattr(obj.ptr(), name); }
+
+inline object getattr(const handle& obj, const handle& name) { return vm->getattr(obj.ptr(), name._as<pkpy::Str>()); }
+
+inline object getattr(const handle& obj, const char* name) { return vm->getattr(obj.ptr(), name); }
+
+inline object getattr(const handle& obj, const handle& name, const handle& default_) {
+    auto attr = vm->getattr(obj.ptr(), name._as<pkpy::Str>(), false);
+    if(attr) { return attr; }
+    return default_;
+}
+
+inline object getattr(const handle& obj, const char* name, const handle& default_) {
+    auto attr = vm->getattr(obj.ptr(), name, false);
+    if(attr) { return attr; }
+    return default_;
+}
+
+inline void setattr(const handle& obj, const handle& name, const handle& value) {
+    vm->setattr(obj.ptr(), name._as<pkpy::Str>(), value.ptr());
+}
+
+inline void setattr(const handle& obj, const char* name, const handle& value) {
+    vm->setattr(obj.ptr(), name, value.ptr());
+}
+
+template <typename T>
+inline bool isinstance(const handle& obj) {
+    return type_visitor::check<T>(obj);
+}
+
+template <>
+inline bool isinstance<handle>(const handle&) = delete;
+
+inline bool isinstance(const handle& obj, const handle& type) {
+    return vm->isinstance(obj.ptr(), type._as<pkpy::Type>());
+}
+
+inline int64_t hash(const handle& obj) { return vm->py_hash(obj.ptr()); }
+
+template <typename T, typename SFINAE = void>
+struct type_caster;
+
+template <typename T>
+handle cast(T&& value, return_value_policy policy, handle parent) {
+    // decay_t can resolve c-array type, but remove_cv_ref_t can't.
+    using underlying_type = std::decay_t<T>;
+
+    if constexpr(std::is_convertible_v<underlying_type, handle>) {
+        return std::forward<T>(value);
+    } else {
+        static_assert(!is_multiple_pointer_v<underlying_type>, "multiple pointer is not supported.");
+        static_assert(!std::is_void_v<std::remove_pointer_t<underlying_type>>,
+                      "void* is not supported, consider using py::capsule.");
+
+        // resolve for automatic policy.
+        if(policy == return_value_policy::automatic) {
+            policy = std::is_pointer_v<underlying_type> ? return_value_policy::take_ownership
+                     : std::is_lvalue_reference_v<T&&>  ? return_value_policy::copy
+                                                        : return_value_policy::move;
+        } else if(policy == return_value_policy::automatic_reference) {
+            policy = std::is_pointer_v<underlying_type> ? return_value_policy::reference
+                     : std::is_lvalue_reference_v<T&&>  ? return_value_policy::copy
+                                                        : return_value_policy::move;
+        }
+
+        return type_caster<underlying_type>::cast(std::forward<T>(value), policy, parent);
+    }
+}
+
+template <typename T>
+T cast(const handle& obj, bool convert) {
+    assert(obj.ptr() != nullptr);
+
+    type_caster<T> caster = {};
+
+    if(caster.load(obj, convert)) {
+        return caster.value;
+    } else {
+        std::string msg = "cast python instance to c++ failed, ";
+        msg += "obj type is: {";
+        msg += type::of(obj).name();
+        msg += "}, target type is: {";
+        msg += type_name<T>();
+        msg += "}.";
+        vm->TypeError(msg);
+        PK_UNREACHABLE();
+    }
+}
+
+struct kwargs_proxy {
+    handle value;
+};
+
+struct args_proxy {
+    handle value;
+
+    kwargs_proxy operator* () { return kwargs_proxy{value}; }
+};
+
+template <typename Derived>
+args_proxy interface<Derived>::operator* () const {
+    return args_proxy{ptr()};
+}
+
+template <typename... Args>
+handle interpreter::vectorcall(const handle& callable, const handle& self, const Args&... args) {
+    vm->s_data.push(callable.ptr());
+
+#if PK_VERSION_MAJOR == 2
+    vm->s_data.push(self ? self.ptr() : PY_NULL);
+#else
+    vm->s_data.push(self ? self.ptr() : pkpy::PY_NULL);
+#endif
+
+    int argc = 0;
+    int kwargsc = 0;
+
+    auto push_arg = [&](const handle& value) {
+        assert(value);
+        vm->s_data.push(value.ptr());
+        argc++;
+    };
+
+    auto push_named_arg = [&](std::string_view name, const handle& value) {
+        assert(value);
+        vm->s_data.push(int_(pkpy::StrName(name).index).ptr());
+        vm->s_data.push(value.ptr());
+        kwargsc++;
+    };
+
+    auto foreach_ = [&](const auto& arg) {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr(std::is_convertible_v<T, handle>) {
+            push_arg(arg);
+        } else if constexpr(std::is_same_v<T, args_proxy>) {
+            pybind11::tuple args = arg.value.template cast<pybind11::tuple>();
+            for(auto item: args) {
+                push_arg(item);
+            }
+        } else if constexpr(std::is_same_v<T, pybind11::arg>) {
+            push_named_arg(arg.name, arg.default_);
+        } else if constexpr(std::is_same_v<T, kwargs_proxy>) {
+            pybind11::dict kwargs = arg.value.template cast<pybind11::dict>();
+            for(auto item: kwargs) {
+                str name = item.first.template cast<str>();
+                push_named_arg(name, item.second);
+            }
+        } else {
+            static_assert(dependent_false<T>, "unsupported type");
+        }
+    };
+    (foreach_(args), ...);
+
+    return vm->vectorcall(argc, kwargsc);
+}
+
+template <typename Derived>
+template <return_value_policy policy, typename... Args>
+inline object interface<Derived>::operator() (Args&&... args) const {
+    auto _cast = [&](auto&& arg) {
+        using T = std::decay_t<decltype(arg)>;
+        if constexpr(std::is_same_v<T, pybind11::arg> || std::is_same_v<T, kwargs_proxy> ||
+                     std::is_same_v<T, args_proxy> || std::is_convertible_v<T, handle>) {
+            return arg;
+        } else {
+            return pybind11::cast(std::forward<decltype(arg)>(arg), policy);
+        }
+    };
+    return interpreter::vectorcall(ptr(), handle(), _cast(std::forward<Args>(args))...);
+}
+
+template <typename... Args>
+void print(Args&&... args) {
+    handle print = getattr(vm->builtins, "print");
+    print(std::forward<Args>(args)...);
+}
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/cast.h b/include/pybind11/internal/cast.h
new file mode 100644
index 00000000..acc0897a
--- /dev/null
+++ b/include/pybind11/internal/cast.h
@@ -0,0 +1,174 @@
+#pragma once
+#include "instance.h"
+#include "accessor.h"
+
+namespace pybind11 {
+
+using pkpy::is_floating_point_v;
+using pkpy::is_integral_v;
+
+template <typename T>
+constexpr inline bool is_string_v =
+    std::is_same_v<T, const char*> || std::is_same_v<T, std::string> || std::is_same_v<T, std::string_view>;
+
+template <typename T>
+constexpr bool is_pointer_v = std::is_pointer_v<T> && !std::is_same_v<T, char*> && !std::is_same_v<T, const char*>;
+
+template <typename T, typename>
+struct type_caster;
+
+template <>
+struct type_caster<bool> {
+    bool value;
+
+    bool load(const handle& src, bool) {
+        if(isinstance<pybind11::bool_>(src)) {
+            value = pkpy::_py_cast<bool>(vm, src.ptr());
+            return true;
+        }
+
+        return false;
+    }
+
+    static handle cast(bool src, return_value_policy, handle) { return src ? vm->True : vm->False; }
+};
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_integral_v<T>>> {
+    T value;
+
+    bool load(const handle& src, bool convert) {
+        if(isinstance<pybind11::int_>(src)) {
+            value = pkpy::_py_cast<T>(vm, src.ptr());
+            return true;
+        }
+
+        return false;
+    }
+
+    static handle cast(T src, return_value_policy, handle) { return pkpy::py_var(vm, src); }
+};
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_floating_point_v<T>>> {
+    T value;
+
+    bool load(const handle& src, bool convert) {
+        if(isinstance<pybind11::float_>(src)) {
+            value = pkpy::_py_cast<T>(vm, src.ptr());
+            return true;
+        }
+
+        if(convert && isinstance<pybind11::int_>(src)) {
+            value = pkpy::_py_cast<int64_t>(vm, src.ptr());
+            return true;
+        }
+
+        return false;
+    }
+
+    static handle cast(T src, return_value_policy, handle) { return pkpy::py_var(vm, src); }
+};
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_string_v<T>>> {
+    T value;
+
+    bool load(const handle& src, bool) {
+        if(isinstance<pybind11::str>(src)) {
+            auto& str = src._as<pkpy::Str>();
+            if constexpr(std::is_same_v<T, std::string>) {
+                value = str;
+            } else if constexpr(std::is_same_v<T, std::string_view>) {
+                value = str;
+            } else if constexpr(std::is_same_v<T, const char*>) {
+                value = str.c_str();
+            }
+            return true;
+        }
+
+        return false;
+    }
+
+    template <typename U>
+    static handle cast(U&& src, return_value_policy, handle) {
+        return str(std::forward<U>(src));
+    }
+};
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_pyobject_v<T>>> {
+    T value;
+
+    bool load(const handle& src, bool) {
+        if(isinstance<T>(src)) {
+            value = src;
+            return true;
+        }
+
+        return false;
+    }
+
+    static handle cast(const handle& src, return_value_policy, handle) { return src; }
+};
+
+template <typename T, typename>
+struct type_caster {
+    struct value_wrapper {
+        T* pointer;
+
+        operator T& () { return *pointer; }
+    };
+
+    value_wrapper value;
+
+    using underlying_type = std::remove_pointer_t<decltype(value.pointer)>;
+
+    bool load(handle src, bool convert) {
+        if(isinstance<underlying_type>(src)) {
+            auto& i = src._as<instance>();
+            value.pointer = &i._as<underlying_type>();
+            return true;
+        }
+
+        return false;
+    }
+
+    template <typename U>
+    static handle cast(U&& value, return_value_policy policy, const handle& parent = handle()) {
+        const auto& info = typeid(underlying_type);
+        auto type = type_visitor::type<underlying_type>();
+        return instance::create(std::forward<U>(value), type, policy, parent.ptr());
+        // TODO: support implicit cast
+    }
+};
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_pointer_v<T> || std::is_reference_v<T>>> {
+    using underlying =
+        std::remove_cv_t<std::conditional_t<is_pointer_v<T>, std::remove_pointer_t<T>, std::remove_reference_t<T>>>;
+
+    struct wrapper {
+        type_caster<underlying> caster;
+
+        operator T () {
+            if constexpr(std::is_pointer_v<T>) {
+                return caster.value.pointer;
+            } else {
+                return caster.value;
+            }
+        }
+    };
+
+    wrapper value;
+
+    bool load(const handle& src, bool convert) { return value.caster.load(src, convert); }
+
+    template <typename U>
+    static handle cast(U&& value, return_value_policy policy, const handle& parent) {
+        return type_caster<underlying>::cast(std::forward<U>(value), policy, parent);
+    }
+};
+
+}  // namespace pybind11
+
diff --git a/include/pybind11/internal/class.h b/include/pybind11/internal/class.h
new file mode 100644
index 00000000..70d850d4
--- /dev/null
+++ b/include/pybind11/internal/class.h
@@ -0,0 +1,186 @@
+#pragma once
+
+#include "module.h"
+#include <vector>
+
+namespace pybind11 {
+
+struct dynamic_attr {};
+
+template <typename T, typename Base = void>
+class class_ : public type {
+protected:
+    handle m_scope;
+
+public:
+    using type::type;
+    using underlying_type = T;
+
+    template <typename... Args>
+    class_(const handle& scope, const char* name, const Args&... args) :
+        m_scope(scope), type(type_visitor::create<T, Base>(scope, name)) {
+        auto& info = type_info::of<T>();
+        info.name = name;
+
+        // bind __new__
+        interpreter::bind_func(m_ptr, pkpy::__new__, -1, [](pkpy::VM* vm, pkpy::ArgsView args) {
+            auto cls = handle(args[0])._as<pkpy::Type>();
+
+            // check if the class has constructor, if not, raise error
+            if(vm->find_name_in_mro(cls, pkpy::__init__) == nullptr) {
+                vm->RuntimeError("if you want to create instance of bound class, you must bind constructor for it");
+            }
+
+            auto var = instance::create(cls, &type_info::of<T>());
+
+            if constexpr(types_count_v<dynamic_attr, Args...> != 0) {
+#if PK_VERSION_MAJOR == 2
+                var.get()->_attr = new pkpy::NameDict();
+#else 
+                var->_enable_instance_dict();
+#endif
+            }
+
+            return var;
+        });
+    }
+
+    /// bind constructor
+    template <typename... Args, typename... Extra>
+    class_& def(init<Args...>, const Extra&... extra) {
+        if constexpr(!std::is_constructible_v<T, Args...>) {
+            static_assert(std::is_constructible_v<T, Args...>, "Invalid constructor arguments");
+        } else {
+            impl::bind_function(
+                *this,
+                "__init__",
+                [](T* self, Args... args) {
+                    new (self) T(args...);
+                },
+                pkpy::BindType::DEFAULT,
+                extra...);
+            return *this;
+        }
+    }
+
+    /// bind member function
+    template <typename Fn, typename... Extra>
+    class_& def(const char* name, Fn&& f, const Extra&... extra) {
+        using first = std::tuple_element_t<0, callable_args_t<remove_cvref_t<Fn>>>;
+        constexpr bool is_first_base_of_v = std::is_base_of_v<remove_cvref_t<first>, T>;
+
+        if constexpr(!is_first_base_of_v) {
+            static_assert(is_first_base_of_v,
+                          "If you want to bind member function, the first argument must be the base class");
+        } else {
+            impl::bind_function(*this, name, std::forward<Fn>(f), pkpy::BindType::DEFAULT, extra...);
+        }
+
+        return *this;
+    }
+
+    /// bind operators
+    template <typename Operator, typename... Extras>
+    class_& def(Operator op, const Extras&... extras) {
+        op.execute(*this, extras...);
+        return *this;
+    }
+
+    // TODO: factory function
+
+    /// bind static function
+    template <typename Fn, typename... Extra>
+    class_& def_static(const char* name, Fn&& f, const Extra&... extra) {
+        impl::bind_function(*this, name, std::forward<Fn>(f), pkpy::BindType::STATICMETHOD, extra...);
+        return *this;
+    }
+
+    template <typename MP, typename... Extras>
+    class_& def_readwrite(const char* name, MP mp, const Extras&... extras) {
+        if constexpr(!std::is_member_object_pointer_v<MP>) {
+            static_assert(std::is_member_object_pointer_v<MP>, "def_readwrite only supports pointer to data member");
+        } else {
+            impl::bind_property(*this, name, mp, mp, extras...);
+        }
+        return *this;
+    }
+
+    template <typename MP, typename... Extras>
+    class_& def_readonly(const char* name, MP mp, const Extras&... extras) {
+        if constexpr(!std::is_member_object_pointer_v<MP>) {
+            static_assert(std::is_member_object_pointer_v<MP>, "def_readonly only supports pointer to data member");
+        } else {
+            impl::bind_property(*this, name, mp, nullptr, extras...);
+        }
+        return *this;
+    }
+
+    template <typename Getter, typename Setter, typename... Extras>
+    class_& def_property(const char* name, Getter&& g, Setter&& s, const Extras&... extras) {
+        impl::bind_property(*this, name, std::forward<Getter>(g), std::forward<Setter>(s), extras...);
+        return *this;
+    }
+
+    template <typename Getter, typename... Extras>
+    class_& def_property_readonly(const char* name, Getter&& mp, const Extras&... extras) {
+        impl::bind_property(*this, name, std::forward<Getter>(mp), nullptr, extras...);
+        return *this;
+    }
+
+    template <typename Var, typename... Extras>
+    class_& def_readwrite_static(const char* name, Var& mp, const Extras&... extras) {
+        static_assert(
+            dependent_false<Var>,
+            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
+        return *this;
+    }
+
+    template <typename Var, typename... Extras>
+    class_& def_readonly_static(const char* name, Var& mp, const Extras&... extras) {
+        static_assert(
+            dependent_false<Var>,
+            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
+        return *this;
+    }
+
+    template <typename Getter, typename Setter, typename... Extras>
+    class_& def_property_static(const char* name, Getter&& g, Setter&& s, const Extras&... extras) {
+        static_assert(
+            dependent_false<Getter>,
+            "define static properties requires metaclass. This is a complex feature with few use cases, so it may never be implemented.");
+        return *this;
+    }
+};
+
+template <typename T, typename... Others>
+class enum_ : public class_<T, Others...> {
+    std::vector<std::pair<const char*, handle>> m_values;
+
+public:
+    using Base = class_<T, Others...>;
+    using class_<T, Others...>::class_;
+
+    template <typename... Args>
+    enum_(const handle& scope, const char* name, Args&&... args) :
+        class_<T, Others...>(scope, name, std::forward<Args>(args)...) {
+        Base::def_property_readonly("value", [](T& self) {
+            return int_(static_cast<std::underlying_type_t<T>>(self));
+        });
+    }
+
+    enum_& value(const char* name, T value) {
+        handle var = type_caster<T>::cast(value, return_value_policy::copy);
+        this->m_ptr->attr().set(name, var.ptr());
+        m_values.emplace_back(name, var);
+        return *this;
+    }
+
+    enum_& export_values() {
+        for(auto& [name, value]: m_values) {
+            Base::m_scope.ptr()->attr().set(name, value.ptr());
+        }
+        return *this;
+    }
+};
+}  // namespace pybind11
+
diff --git a/include/pybind11/internal/cpp_function.h b/include/pybind11/internal/cpp_function.h
new file mode 100644
index 00000000..fa7a4364
--- /dev/null
+++ b/include/pybind11/internal/cpp_function.h
@@ -0,0 +1,551 @@
+#pragma once
+#include "cast.h"
+#include <map>
+
+namespace pybind11 {
+
+// append the overload to the beginning of the overload list
+struct prepend {};
+
+template <typename... Args>
+struct init {};
+
+//  TODO: support more customized tags
+//
+// template <std::size_t Nurse, std::size_t... Patients>
+// struct keep_alive {};
+//
+// template <typename T>
+// struct call_guard {
+//     static_assert(std::is_default_constructible_v<T>, "call_guard must be default constructible");
+// };
+//
+//  struct kw_only {};
+//
+//  struct pos_only {};
+
+class cpp_function : public function {
+    PYBIND11_TYPE_IMPLEMENT(function, pkpy::NativeFunc, vm->tp_native_func);
+
+public:
+    template <typename Fn, typename... Extras>
+    cpp_function(Fn&& f, const Extras&... extras) {}
+
+    template <typename T>
+    decltype(auto) get_userdata_as() {
+#if PK_VERSION_MAJOR == 2
+        return self()._userdata.as<T>();
+#else
+        return self()._userdata._cast<T>();
+#endif
+    }
+
+    template <typename T>
+    void set_userdata(T&& value) {
+        self()._userdata = std::forward<T>(value);
+    }
+};
+
+}  // namespace pybind11
+
+namespace pybind11::impl {
+
+template <typename Callable,
+          typename Extra,
+          typename Args = callable_args_t<Callable>,
+          typename IndexSequence = std::make_index_sequence<std::tuple_size_v<Args>>>
+struct template_parser;
+
+class function_record {
+private:
+    template <typename C, typename E, typename A, typename I>
+    friend struct template_parser;
+
+    struct arguments_t {
+        std::vector<pkpy::StrName> names;
+        std::vector<handle> defaults;
+    };
+
+    using destructor_t = void (*)(function_record*);
+    using wrapper_t = handle (*)(function_record&, pkpy::ArgsView, bool convert, handle parent);
+
+    static_assert(std::is_trivially_copyable_v<pkpy::StrName>);
+
+private:
+    union {
+        void* data;
+        char buffer[16];
+    };
+
+    wrapper_t wrapper = nullptr;
+    function_record* next = nullptr;
+    arguments_t* arguments = nullptr;
+    destructor_t destructor = nullptr;
+    const char* signature = nullptr;
+    return_value_policy policy = return_value_policy::automatic;
+
+public:
+    template <typename Fn, typename... Extras>
+    function_record(Fn&& f, const Extras&... extras) {
+        using Callable = std::decay_t<Fn>;
+
+        if constexpr(std::is_trivially_copyable_v<Callable> && sizeof(Callable) <= sizeof(buffer)) {
+            // if the callable object is trivially copyable and the size is less than 16 bytes, store it in the
+            // buffer
+            new (buffer) auto(std::forward<Fn>(f));
+            destructor = [](function_record* self) {
+                reinterpret_cast<Callable*>(self->buffer)->~Callable();
+            };
+        } else {
+            // otherwise, store it in the heap
+            data = new auto(std::forward<Fn>(f));
+            destructor = [](function_record* self) {
+                delete static_cast<Callable*>(self->data);
+            };
+        }
+
+        using Parser = template_parser<Callable, std::tuple<Extras...>>;
+        Parser::initialize(*this, extras...);
+        wrapper = Parser::wrapper;
+    }
+
+    function_record(const function_record&) = delete;
+    function_record& operator= (const function_record&) = delete;
+    function_record& operator= (function_record&&) = delete;
+
+    function_record(function_record&& other) noexcept {
+        std::memcpy(this, &other, sizeof(function_record));
+        std::memset(&other, 0, sizeof(function_record));
+    }
+
+    ~function_record() {
+        if(destructor) { destructor(this); }
+        if(arguments) { delete arguments; }
+        if(next) { delete next; }
+        if(signature) { delete[] signature; }
+    }
+
+    void append(function_record* record) {
+        function_record* p = this;
+        while(p->next) {
+            p = p->next;
+        }
+        p->next = record;
+    }
+
+    template <typename T>
+    T& _as() {
+        if constexpr(std::is_trivially_copyable_v<T> && sizeof(T) <= sizeof(buffer)) {
+            return *reinterpret_cast<T*>(buffer);
+        } else {
+            return *static_cast<T*>(data);
+        }
+    }
+
+    handle operator() (pkpy::ArgsView view) {
+        function_record* p = this;
+        // foreach function record and call the function with not convert
+        while(p != nullptr) {
+            handle result = p->wrapper(*p, view, false, {});
+            if(result) { return result; }
+            p = p->next;
+        }
+
+        p = this;
+        // foreach function record and call the function with convert
+        while(p != nullptr) {
+            handle result = p->wrapper(*p, view, true, {});
+            if(result) { return result; }
+            p = p->next;
+        }
+
+        std::string msg = "no matching function found, function signature:\n";
+        std::size_t index = 0;
+        p = this;
+        while(p != nullptr) {
+            msg += "    ";
+            msg += p->signature;
+            msg += "\n";
+            p = p->next;
+        }
+        vm->TypeError(msg);
+        PK_UNREACHABLE();
+    }
+};
+
+template <typename Fn, std::size_t... Is, typename... Args>
+handle invoke(Fn&& fn,
+              std::index_sequence<Is...>,
+              std::tuple<type_caster<Args>...>& casters,
+              return_value_policy policy,
+              handle parent) {
+    using underlying_type = std::decay_t<Fn>;
+    using return_type = callable_return_t<underlying_type>;
+
+    constexpr bool is_void = std::is_void_v<return_type>;
+    constexpr bool is_member_function_pointer = std::is_member_function_pointer_v<underlying_type>;
+
+    if constexpr(is_member_function_pointer) {
+        // helper function to unpack the arguments to call the member pointer
+        auto unpack = [&](class_type_t<underlying_type>& self, auto&... args) {
+            return (self.*fn)(args...);
+        };
+
+        if constexpr(!is_void) {
+            return pybind11::cast(unpack(std::get<Is>(casters).value...), policy, parent);
+        } else {
+            unpack(std::get<Is>(casters).value...);
+            return vm->None;
+        }
+    } else {
+        if constexpr(!is_void) {
+            return pybind11::cast(fn(std::get<Is>(casters).value...), policy, parent);
+        } else {
+            fn(std::get<Is>(casters).value...);
+            return vm->None;
+        }
+    }
+}
+
+struct arguments_info_t {
+    int argc = 0;
+    int args_pos = -1;
+    int kwargs_pos = -1;
+};
+
+struct extras_info_t {
+    int doc_pos = -1;
+    int named_argc = 0;
+    int policy_pos = -1;
+};
+
+template <typename Callable, typename... Extras, typename... Args, std::size_t... Is>
+struct template_parser<Callable, std::tuple<Extras...>, std::tuple<Args...>, std::index_sequence<Is...>> {
+    constexpr static arguments_info_t parse_arguments() {
+        constexpr auto args_count = types_count_v<args, Args...>;
+        constexpr auto kwargs_count = types_count_v<kwargs, Args...>;
+
+        static_assert(args_count <= 1, "py::args can occur at most once");
+        static_assert(kwargs_count <= 1, "py::kwargs can occur at most once");
+
+        constexpr auto args_pos = type_index_v<args, Args...>;
+        constexpr auto kwargs_pos = type_index_v<kwargs, Args...>;
+
+        if constexpr(kwargs_count == 1) {
+            static_assert(kwargs_pos == sizeof...(Args) - 1, "py::kwargs must be the last argument");
+
+            // FIXME: temporarily, args and kwargs must be at the end of the arguments list
+            if constexpr(args_count == 1) {
+                static_assert(args_pos == kwargs_pos - 1, "py::args must be before py::kwargs");
+            }
+        }
+
+        return {sizeof...(Args), args_pos, kwargs_pos};
+    }
+
+    constexpr static extras_info_t parse_extras() {
+        constexpr auto doc_count = types_count_v<const char*, Extras...>;
+        constexpr auto policy_count = types_count_v<return_value_policy, Extras...>;
+
+        static_assert(doc_count <= 1, "doc can occur at most once");
+        static_assert(policy_count <= 1, "return_value_policy can occur at most once");
+
+        constexpr auto doc_pos = type_index_v<const char*, Extras...>;
+        constexpr auto policy_pos = type_index_v<return_value_policy, Extras...>;
+
+        constexpr auto named_argc = types_count_v<arg, Extras...>;
+        constexpr auto normal_argc =
+            sizeof...(Args) - (arguments_info.args_pos != -1) - (arguments_info.kwargs_pos != -1);
+        static_assert(named_argc == 0 || named_argc == normal_argc,
+                      "named arguments must be the same as the number of function arguments");
+
+        return {doc_pos, named_argc, policy_pos};
+    }
+
+    constexpr inline static auto arguments_info = parse_arguments();
+    constexpr inline static auto extras_info = parse_extras();
+
+    static void initialize(function_record& record, const Extras&... extras) {
+        auto extras_tuple = std::make_tuple(extras...);
+        constexpr static bool has_named_args = (extras_info.named_argc > 0);
+        // set return value policy
+        if constexpr(extras_info.policy_pos != -1) { record.policy = std::get<extras_info.policy_pos>(extras_tuple); }
+
+        // TODO: set others
+
+        // set default arguments
+        if constexpr(has_named_args) {
+            record.arguments = new function_record::arguments_t();
+
+            auto add_arguments = [&](const auto& arg) {
+                if constexpr(std::is_same_v<pybind11::arg, remove_cvref_t<decltype(arg)>>) {
+                    auto& arguments = *record.arguments;
+                    arguments.names.emplace_back(arg.name);
+                    arguments.defaults.emplace_back(arg.default_);
+                }
+            };
+
+            (add_arguments(extras), ...);
+        }
+
+        // set signature
+        {
+            std::string sig = "(";
+            std::size_t index = 0;
+            auto append = [&](auto _t) {
+                using T = pybind11_decay_t<typename decltype(_t)::type>;
+                if constexpr(std::is_same_v<T, args>) {
+                    sig += "*args";
+                } else if constexpr(std::is_same_v<T, kwargs>) {
+                    sig += "**kwargs";
+                } else if constexpr(has_named_args) {
+                    sig += record.arguments->names[index].c_str();
+                    sig += ": ";
+                    sig += type_info::of<T>().name;
+                    if(record.arguments->defaults[index]) {
+                        sig += " = ";
+                        sig += record.arguments->defaults[index].repr();
+                    }
+                } else {
+                    sig += "_: ";
+                    sig += type_info::of<T>().name;
+                }
+
+                if(index + 1 < arguments_info.argc) { sig += ", "; }
+                index++;
+            };
+            (append(type_identity<Args>{}), ...);
+            sig += ")";
+            char* buffer = new char[sig.size() + 1];
+            std::memcpy(buffer, sig.data(), sig.size());
+            buffer[sig.size()] = '\0';
+            record.signature = buffer;
+        }
+    }
+
+    static handle wrapper(function_record& record, pkpy::ArgsView view, bool convert, handle parent) {
+        constexpr auto argc = arguments_info.argc;
+        constexpr auto named_argc = extras_info.named_argc;
+        constexpr auto args_pos = arguments_info.args_pos;
+        constexpr auto kwargs_pos = arguments_info.kwargs_pos;
+        constexpr auto normal_argc = argc - (args_pos != -1) - (kwargs_pos != -1);
+
+        // avoid gc call in bound function
+        vm->heap.gc_scope_lock();
+
+        // add 1 to avoid zero-size array when argc is 0
+        handle stack[argc + 1] = {};
+
+        // ensure the number of passed arguments is no greater than the number of parameters
+        if(args_pos == -1 && view.size() > normal_argc) { return handle(); }
+
+        // if have default arguments, load them
+        if constexpr(named_argc > 0) {
+            auto& defaults = record.arguments->defaults;
+            std::memcpy(stack, defaults.data(), defaults.size() * sizeof(handle));
+        }
+
+        // load arguments from call arguments
+        const auto size = std::min(view.size(), normal_argc);
+        std::memcpy(stack, view.begin(), size * sizeof(handle));
+
+        // pack the args
+        if constexpr(args_pos != -1) {
+            const auto n = std::max(view.size() - normal_argc, 0);
+            tuple args = tuple(n);
+            for(std::size_t i = 0; i < n; ++i) {
+                args[i] = view[normal_argc + i];
+            }
+            stack[args_pos] = args;
+        }
+
+        // resolve keyword arguments
+        const auto n = vm->s_data._sp - view.end();
+        std::size_t index = 0;
+
+        if constexpr(named_argc > 0) {
+            std::size_t arg_index = 0;
+            auto& arguments = *record.arguments;
+
+            while(arg_index < named_argc && index < n) {
+                const auto key = pkpy::_py_cast<pkpy::i64>(vm, view.end()[index]);
+                const auto value = view.end()[index + 1];
+                const auto name = pkpy::StrName(key);
+                auto& arg_name = record.arguments->names[arg_index];
+
+                if(name == arg_name) {
+                    stack[arg_index] = value;
+                    index += 2;
+                }
+
+                arg_index += 1;
+            }
+        }
+
+        // pack the kwargs
+        if constexpr(kwargs_pos != -1) {
+            dict kwargs;
+            while(index < n) {
+                const auto key = pkpy::_py_cast<pkpy::i64>(vm, view.end()[index]);
+                const str name = str(pkpy::StrName(key).sv());
+                kwargs[name] = view.end()[index + 1];
+                index += 2;
+            }
+            stack[kwargs_pos] = kwargs;
+        }
+
+        // if have rest keyword arguments, call fails
+        if(index != n) { return handle(); }
+
+        // check if all the arguments are valid
+        for(std::size_t i = 0; i < argc; ++i) {
+            if(!stack[i]) { return handle(); }
+        }
+
+        // ok, all the arguments are valid, call the function
+        std::tuple<type_caster<Args>...> casters;
+
+        // check type compatibility
+        if(((std::get<Is>(casters).load(stack[Is], convert)) && ...)) {
+            return invoke(record._as<Callable>(), std::index_sequence<Is...>{}, casters, record.policy, parent);
+        }
+
+        return handle();
+    }
+};
+
+inline auto _wrapper(pkpy::VM* vm, pkpy::ArgsView view) {
+    auto&& record = unpack<function_record>(view);
+    return record(view).ptr();
+}
+
+template <typename Fn, typename... Extras>
+handle bind_function(const handle& obj, const char* name, Fn&& fn, pkpy::BindType type, const Extras&... extras) {
+    // do not use cpp_function directly to avoid unnecessary reference count change
+    pkpy::PyVar var = obj.ptr();
+    cpp_function callable = var->attr().try_get(name);
+
+    // if the function is not bound yet, bind it
+    if(!callable) {
+        auto record = function_record(std::forward<Fn>(fn), extras...);
+        void* data = interpreter::take_ownership(std::move(record));
+        callable = interpreter::bind_func(var, name, -1, _wrapper, data);
+    } else {
+        function_record* record = new function_record(std::forward<Fn>(fn), extras...);
+        function_record* last = callable.get_userdata_as<function_record*>();
+
+        if constexpr((types_count_v<prepend, Extras...> != 0)) {
+            // if prepend is specified, append the new record to the beginning of the list
+            fn.set_userdata(record);
+            record->append(last);
+        } else {
+            // otherwise, append the new record to the end of the list
+            last->append(record);
+        }
+    }
+
+    return callable;
+}
+
+}  // namespace pybind11::impl
+
+namespace pybind11::impl {
+
+template <typename Getter>
+pkpy::PyVar getter_wrapper(pkpy::VM* vm, pkpy::ArgsView view) {
+    handle result = vm->None;
+    auto&& getter = unpack<Getter>(view);
+    constexpr auto policy = return_value_policy::reference_internal;
+
+    if constexpr(std::is_member_pointer_v<Getter>) {
+        using Self = class_type_t<Getter>;
+        auto& self = handle(view[0])._as<instance>()._as<Self>();
+
+        if constexpr(std::is_member_object_pointer_v<Getter>) {
+            // specialize for pointer to data member
+            result = cast(self.*getter, policy, view[0]);
+        } else {
+            // specialize for pointer to member function
+            result = cast((self.*getter)(), policy, view[0]);
+        }
+    } else {
+        // specialize for function pointer and lambda
+        using Self = remove_cvref_t<std::tuple_element_t<0, callable_args_t<Getter>>>;
+        auto& self = handle(view[0])._as<instance>()._as<Self>();
+
+        result = cast(getter(self), policy, view[0]);
+    }
+
+    return result.ptr();
+}
+
+template <typename Setter>
+pkpy::PyVar setter_wrapper(pkpy::VM* vm, pkpy::ArgsView view) {
+    auto&& setter = unpack<Setter>(view);
+
+    if constexpr(std::is_member_pointer_v<Setter>) {
+        using Self = class_type_t<Setter>;
+        auto& self = handle(view[0])._as<instance>()._as<Self>();
+
+        if constexpr(std::is_member_object_pointer_v<Setter>) {
+            // specialize for pointer to data member
+            type_caster<member_type_t<Setter>> caster;
+            if(caster.load(view[1], true)) {
+                self.*setter = caster.value;
+                return vm->None;
+            }
+        } else {
+            // specialize for pointer to member function
+            type_caster<std::tuple_element_t<1, callable_args_t<Setter>>> caster;
+            if(caster.load(view[1], true)) {
+                (self.*setter)(caster.value);
+                return vm->None;
+            }
+        }
+    } else {
+        // specialize for function pointer and lambda
+        using Self = remove_cvref_t<std::tuple_element_t<0, callable_args_t<Setter>>>;
+        auto& self = handle(view[0])._as<instance>()._as<Self>();
+
+        type_caster<std::tuple_element_t<1, callable_args_t<Setter>>> caster;
+        if(caster.load(view[1], true)) {
+            setter(self, caster.value);
+            return vm->None;
+        }
+    }
+
+    vm->TypeError("Unexpected argument type");
+    PK_UNREACHABLE();
+}
+
+template <typename Getter, typename Setter, typename... Extras>
+handle bind_property(const handle& obj, const char* name, Getter&& getter_, Setter&& setter_, const Extras&... extras) {
+    handle getter = none();
+    handle setter = none();
+    using Wrapper = pkpy::PyVar (*)(pkpy::VM*, pkpy::ArgsView);
+
+    constexpr auto create = [](Wrapper wrapper, int argc, auto&& f) {
+        if constexpr(need_host<remove_cvref_t<decltype(f)>>) {
+            // otherwise, store it in the type_info
+            void* data = interpreter::take_ownership(std::forward<decltype(f)>(f));
+            // store the index in the object
+            return vm->heap.gcnew<pkpy::NativeFunc>(vm->tp_native_func, wrapper, argc, data);
+        } else {
+            // if the function is trivially copyable and the size is less than 16 bytes, store it in the object
+            // directly
+            return vm->heap.gcnew<pkpy::NativeFunc>(vm->tp_native_func, wrapper, argc, f);
+        }
+    };
+
+    getter = create(impl::getter_wrapper<std::decay_t<Getter>>, 1, std::forward<Getter>(getter_));
+
+    if constexpr(!std::is_same_v<Setter, std::nullptr_t>) {
+        setter = create(impl::setter_wrapper<std::decay_t<Setter>>, 2, std::forward<Setter>(setter_));
+    }
+
+    handle property = pybind11::property(getter, setter);
+    setattr(obj, name, property);
+    return property;
+}
+
+}  // namespace pybind11::impl
diff --git a/include/pybind11/internal/instance.h b/include/pybind11/internal/instance.h
new file mode 100644
index 00000000..03beeca1
--- /dev/null
+++ b/include/pybind11/internal/instance.h
@@ -0,0 +1,142 @@
+#pragma once
+#include "kernel.h"
+
+namespace pybind11 {
+
+struct type_info {
+    std::string_view name;
+    std::size_t size;
+    std::size_t alignment;
+    void (*destructor)(void*);
+    const std::type_info* type;
+
+    template <typename T>
+    static type_info& of() {
+        static_assert(!std::is_reference_v<T> && !std::is_const_v<std::remove_reference_t<T>>,
+                      "T must not be a reference type or const type.");
+        static type_info info = {
+            type_name<T>(),
+            sizeof(T),
+            alignof(T),
+            [](void* ptr) {
+                ((T*)ptr)->~T();
+                operator delete (ptr);
+            },
+            &typeid(T),
+        };
+        return info;
+    }
+};
+
+// all registered C++ class will be ensured as instance type.
+class instance {
+public:
+    // use to record the type information of C++ class.
+
+private:
+    enum Flag {
+        None = 0,
+        Own = 1 << 0,  // if the instance is owned by C++ side.
+        Ref = 1 << 1,  // need to mark the parent object.
+    };
+
+    Flag flag;
+    void* data;
+    const type_info* type;
+    pkpy::PyVar parent;
+
+public:
+    instance() noexcept : flag(Flag::None), data(nullptr), type(nullptr), parent(nullptr) {}
+
+    instance(const instance&) = delete;
+
+    instance(instance&& other) noexcept : flag(other.flag), data(other.data), type(other.type), parent(other.parent) {
+        other.flag = Flag::None;
+        other.data = nullptr;
+        other.type = nullptr;
+        other.parent = nullptr;
+    }
+
+    static pkpy::PyVar create(pkpy::Type type, const type_info* info) noexcept {
+        instance instance;
+        instance.type = info;
+        instance.data = operator new (info->size);
+        instance.flag = Flag::Own;
+        return vm->heap.gcnew<pybind11::instance>(type, std::move(instance));
+    }
+
+    template <typename T>
+    static pkpy::PyVar create(T&& value,
+                              pkpy::Type type,
+                              return_value_policy policy = return_value_policy::automatic_reference,
+                              pkpy::PyVar parent = nullptr) noexcept {
+        using underlying_type = remove_cvref_t<T>;
+
+        auto& _value = [&]() -> auto& {
+            // note that, pybind11 will ignore the const qualifier.
+            // in fact, try to modify a const value will result in undefined behavior.
+            if constexpr(std::is_pointer_v<underlying_type>) {
+                return *reinterpret_cast<underlying_type*>(value);
+            } else {
+                return const_cast<underlying_type&>(value);
+            }
+        }();
+
+        using primary = std::remove_pointer_t<underlying_type>;
+        instance instance;
+        instance.type = &type_info::of<primary>();
+
+        if(policy == return_value_policy::take_ownership) {
+            instance.data = &_value;
+            instance.flag = Flag::Own;
+        } else if(policy == return_value_policy::copy) {
+            if constexpr(std::is_copy_constructible_v<primary>) {
+                instance.data = ::new auto(_value);
+                instance.flag = Flag::Own;
+            } else {
+                std::string msg = "cannot use copy policy on non-copyable type: ";
+                msg += type_name<primary>();
+                vm->RuntimeError(msg);
+            }
+        } else if(policy == return_value_policy::move) {
+            if constexpr(std::is_move_constructible_v<primary>) {
+                instance.data = ::new auto(std::move(_value));
+                instance.flag = Flag::Own;
+            } else {
+                std::string msg = "cannot use move policy on non-moveable type: ";
+                msg += type_name<primary>();
+                vm->RuntimeError(msg);
+            }
+        } else if(policy == return_value_policy::reference) {
+            instance.data = &_value;
+            instance.flag = Flag::None;
+        } else if(policy == return_value_policy::reference_internal) {
+            instance.data = &_value;
+            instance.flag = Flag::Ref;
+            instance.parent = parent;
+        }
+
+        return vm->heap.gcnew<pybind11::instance>(type, std::move(instance));
+    }
+
+    ~instance() {
+        if(flag & Flag::Own) { type->destructor(data); }
+    }
+
+    template <typename T>
+    T& _as() noexcept {
+        return *static_cast<T*>(data);
+    }
+
+#if PK_VERSION_MAJOR == 2
+    void _gc_mark(pkpy::VM* vm) const noexcept {
+        if(parent && (flag & Flag::Ref)) { PK_OBJ_MARK(parent); }
+    }
+#else
+    void _gc_mark() const noexcept {
+        if(parent && (flag & Flag::Ref)) { PK_OBJ_MARK(parent); }
+    }
+#endif
+};
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/kernel.h b/include/pybind11/internal/kernel.h
new file mode 100644
index 00000000..bb117712
--- /dev/null
+++ b/include/pybind11/internal/kernel.h
@@ -0,0 +1,224 @@
+#pragma once
+#include <vector>
+#include <cassert>
+#include <pocketpy.h>
+
+#include "type_traits.h"
+
+namespace pybind11::impl {
+struct capsule {
+    void* ptr;
+    void (*destructor)(void*);
+
+    template <typename T>
+    capsule(T&& value) :
+        ptr(new auto(std::forward<T>(value))), destructor([](void* ptr) {
+            delete static_cast<std::decay_t<T>*>(ptr);
+        }) {}
+
+    capsule(void* ptr, void (*destructor)(void*)) : ptr(ptr), destructor(destructor) {}
+
+    capsule(const capsule&) = delete;
+
+    capsule(capsule&& other) noexcept : ptr(other.ptr), destructor(other.destructor) {
+        other.ptr = nullptr;
+        other.destructor = nullptr;
+    }
+
+    ~capsule() {
+        if(ptr != nullptr && destructor != nullptr) destructor(ptr);
+    }
+};
+}  // namespace pybind11::impl
+
+namespace pybind11 {
+
+class handle;
+class object;
+class iterator;
+class str;
+class arg;
+struct args_proxy;
+struct kwargs_proxy;
+
+inline pkpy::VM* vm = nullptr;
+
+class interpreter {
+    inline static std::vector<impl::capsule>* _capsules = nullptr;
+    inline static std::vector<void (*)()>* _init = nullptr;
+
+public:
+    inline static void initialize(bool enable_os = true) {
+        if(vm == nullptr) {
+            vm = new pkpy::VM();
+            if(_init != nullptr) {
+                for(auto& fn: *_init)
+                    fn();
+            }
+        }
+    }
+
+    inline static void finalize() {
+        if(_capsules != nullptr) {
+            delete _capsules;
+            _capsules = nullptr;
+        }
+
+        if(vm != nullptr) {
+            delete vm;
+            vm = nullptr;
+        }
+    }
+
+    template <typename T>
+    inline static void* take_ownership(T&& value) {
+        if(_capsules == nullptr) _capsules = new std::vector<impl::capsule>();
+        _capsules->emplace_back(std::forward<T>(value));
+        return _capsules->back().ptr;
+    }
+
+    inline static void register_init(void (*init)()) {
+        if(_init == nullptr) _init = new std::vector<void (*)()>();
+        _init->push_back(init);
+    }
+
+    inline static pkpy::PyVar bind_func(pkpy::PyVar scope,
+                                        pkpy::StrName name,
+                                        int argc,
+                                        pkpy::NativeFuncC fn,
+                                        pkpy::any any = {},
+                                        pkpy::BindType type = pkpy::BindType::DEFAULT) {
+#if PK_VERSION_MAJOR == 2
+        return vm->bind_func(scope.get(), name, argc, fn, any, type);
+#else
+        return vm->bind_func(scope, name, argc, fn, std::move(any), type);
+#endif
+    }
+
+    template <typename... Args>
+    inline static handle vectorcall(const handle& self, const handle& func, const Args&... args);
+};
+
+template <typename T>
+constexpr inline bool need_host = !(std::is_trivially_copyable_v<T> && (sizeof(T) <= 8));
+
+template <typename T>
+decltype(auto) unpack(pkpy::ArgsView view) {
+    if constexpr(need_host<T>) {
+        void* data = pkpy::lambda_get_userdata<void*>(view.begin());
+        return *static_cast<T*>(data);
+    } else {
+        return pkpy::lambda_get_userdata<T>(view.begin());
+    }
+}
+
+template <typename policy>
+class accessor;
+
+namespace policy {
+struct attr;
+struct item;
+struct tuple;
+struct list;
+struct dict;
+}  // namespace policy
+
+using attr_accessor = accessor<policy::attr>;
+using item_accessor = accessor<policy::item>;
+using tuple_accessor = accessor<policy::tuple>;
+using list_accessor = accessor<policy::list>;
+using dict_accessor = accessor<policy::dict>;
+
+template <typename T>
+T cast(const handle& obj, bool convert = false);
+
+enum class return_value_policy : uint8_t {
+    /**
+     *  This is the default return value policy, which falls back to the policy
+     *  return_value_policy::take_ownership when the return value is a pointer.
+     *  Otherwise, it uses return_value::move or return_value::copy for rvalue
+     *  and lvalue references, respectively. See below for a description of what
+     *  all of these different policies do.
+     */
+    automatic = 0,
+
+    /**
+     *  As above, but use policy return_value_policy::reference when the return
+     *  value is a pointer. This is the default conversion policy for function
+     *  arguments when calling Python functions manually from C++ code (i.e. via
+     *  handle::operator()). You probably won't need to use this.
+     */
+    automatic_reference,
+
+    /**
+     *  Reference an existing object (i.e. do not create a new copy) and take
+     *  ownership. Python will call the destructor and delete operator when the
+     *  object's reference count reaches zero. Undefined behavior ensues when
+     *  the C++ side does the same..
+     */
+    take_ownership,
+
+    /**
+     *  Create a new copy of the returned object, which will be owned by
+     *  Python. This policy is comparably safe because the lifetimes of the two
+     *  instances are decoupled.
+     */
+    copy,
+
+    /**
+     *  Use std::move to move the return value contents into a new instance
+     *  that will be owned by Python. This policy is comparably safe because the
+     *  lifetimes of the two instances (move source and destination) are
+     *  decoupled.
+     */
+    move,
+
+    /**
+     *  Reference an existing object, but do not take ownership. The C++ side
+     *  is responsible for managing the object's lifetime and deallocating it
+     *  when it is no longer used. Warning: undefined behavior will ensue when
+     *  the C++ side deletes an object that is still referenced and used by
+     *  Python.
+     */
+    reference,
+
+    /**
+     *  This policy only applies to methods and properties. It references the
+     *  object without taking ownership similar to the above
+     *  return_value_policy::reference policy. In contrast to that policy, the
+     *  function or property's implicit this argument (called the parent) is
+     *  considered to be the the owner of the return value (the child).
+     *  pybind11 then couples the lifetime of the parent to the child via a
+     *  reference relationship that ensures that the parent cannot be garbage
+     *  collected while Python is still using the child. More advanced
+     *  variations of this scheme are also possible using combinations of
+     *  return_value_policy::reference and the keep_alive call policy
+     */
+    reference_internal
+};
+
+struct empty {};
+
+template <typename... Args>
+void print(Args&&... args);
+
+class object;
+
+template <typename T>
+constexpr inline bool is_pyobject_v = std::is_base_of_v<object, T>;
+
+#if PK_VERSION_MAJOR == 2
+using error_already_set = pkpy::TopLevelException;
+#else
+class error_already_set : std::exception {
+public:
+    error_already_set() = default;
+
+    const char* what() const noexcept override { return "An error occurred while calling a Python function."; }
+};
+#endif
+
+inline void setattr(const handle& obj, const handle& name, const handle& value);
+inline void setattr(const handle& obj, const char* name, const handle& value);
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/module.h b/include/pybind11/internal/module.h
new file mode 100644
index 00000000..420b11fc
--- /dev/null
+++ b/include/pybind11/internal/module.h
@@ -0,0 +1,48 @@
+#pragma once
+#include "cpp_function.h"
+
+namespace pybind11 {
+
+class module_ : public object {
+
+public:
+    using object::object;
+
+    static module_ __main__() { return vm->_main; }
+
+    static module_ import(const char* name) {
+        if(name == std::string_view{"__main__"}) {
+            return vm->_main;
+        } else {
+            return vm->py_import(name, false);
+        }
+    }
+
+    module_ def_submodule(const char* name, const char* doc = nullptr) {
+        auto package = this->package()._as<pkpy::Str>() + "." + this->name()._as<pkpy::Str>();
+        auto m = vm->new_module(name, package);
+        setattr(*this, name, m);
+        return m;
+    }
+
+    template <typename Fn, typename... Extras>
+    module_& def(const char* name, Fn&& fn, const Extras... extras) {
+        impl::bind_function(*this, name, std::forward<Fn>(fn), pkpy::BindType::DEFAULT, extras...);
+        return *this;
+    }
+};
+
+#define PYBIND11_EMBEDDED_MODULE(name, variable)                                                                       \
+    static void _pybind11_register_##name(pybind11::module_& variable);                                                \
+    namespace pybind11::impl {                                                                                         \
+    auto _module_##name = [] {                                                                                         \
+        interpreter::register_init([] {                                                                                \
+            pybind11::module_ m = vm->new_module(#name, "");                                                           \
+            _pybind11_register_##name(m);                                                                              \
+        });                                                                                                            \
+        return 1;                                                                                                      \
+    }();                                                                                                               \
+    }                                                                                                                  \
+    static void _pybind11_register_##name(pybind11::module_& variable)
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/object.h b/include/pybind11/internal/object.h
new file mode 100644
index 00000000..ef1ffe15
--- /dev/null
+++ b/include/pybind11/internal/object.h
@@ -0,0 +1,268 @@
+#pragma once
+#include "instance.h"
+
+namespace pybind11 {
+
+template <typename Derived>
+class interface {
+private:
+    pkpy::PyVar ptr() const { return static_cast<const Derived*>(this)->ptr(); }
+
+public:
+    bool is_none() const {
+#if PK_VERSION_MAJOR == 2
+        return ptr().operator== (vm->None.get());
+#else
+        return ptr() == vm->None;
+#endif
+    }
+
+    bool is(const interface& other) const {
+#if PK_VERSION_MAJOR == 2
+        return ptr().operator== (other.ptr().get());
+#else
+        return ptr() == other.ptr();
+#endif
+    }
+
+    bool in(const interface& other) const {
+        return pybind11::cast<bool>(vm->call(vm->py_op("contains"), other.ptr(), ptr()));
+    }
+
+    bool contains(const interface& other) const {
+        return pybind11::cast<bool>(vm->call(vm->py_op("contains"), ptr(), other.ptr()));
+    }
+
+protected:
+    attr_accessor attr(pkpy::StrName key) const;
+
+public:
+    iterator begin() const;
+    iterator end() const;
+
+    attr_accessor attr(const char* key) const;
+    attr_accessor attr(const handle& key) const;
+    attr_accessor doc() const;
+
+    item_accessor operator[] (int index) const;
+    item_accessor operator[] (const char* key) const;
+    item_accessor operator[] (const handle& key) const;
+
+    args_proxy operator* () const;
+    object operator- () const;
+    object operator~() const;
+
+    template <return_value_policy policy = return_value_policy::automatic, typename... Args>
+    object operator() (Args&&... args) const;
+
+    str package() const;
+    str name() const;
+    str repr() const;
+
+public:
+    template <typename T>
+    T cast() const {
+        return pybind11::cast<T>(ptr());
+    }
+
+    // this is a internal function, use to interact with pocketpy python
+    template <typename T>
+    decltype(auto) _as() const {
+        static_assert(!std::is_reference_v<T>, "T must not be a reference type.");
+#if PK_VERSION_MAJOR == 2
+        if constexpr(pkpy::is_sso_v<T>) {
+            return pkpy::_py_cast<T>(vm, ptr());
+        } else {
+            return ptr().template obj_get<T>();
+        }
+#else
+        return (((pkpy::Py_<T>*)ptr())->_value);
+#endif
+    }
+};
+
+/// a lightweight wrapper for python objects
+class handle : public interface<handle> {
+protected:
+    mutable pkpy::PyVar m_ptr = nullptr;
+
+public:
+    handle() = default;
+    handle(const handle& h) = default;
+    handle& operator= (const handle& other) = default;
+
+    handle(std::nullptr_t) = delete;
+
+    handle(pkpy::PyVar ptr) : m_ptr(ptr) {}
+
+#if PK_VERSION_MAJOR == 2
+    handle(pkpy::PyObject* ptr) : m_ptr(ptr) {}
+#endif
+
+    pkpy::PyVar ptr() const { return m_ptr; }
+
+    explicit operator bool () const { return m_ptr != nullptr; }
+};
+
+// a helper class to visit type
+struct type_visitor {
+
+    template <typename T>
+    constexpr static bool is_type = std::is_same_v<pkpy::Type, std::decay_t<decltype(T::type_or_check())>>;
+
+    template <typename T>
+    static pkpy::Type type() {
+        if constexpr(is_pyobject_v<T>) {
+            if constexpr(is_type<T>) {
+                // for some type, they have according type in python, e.g. bool, int, float
+                // so just return the according type
+                return T::type_or_check();
+            } else {
+                // for other type, they don't have according type in python, like iterable, iterator
+                static_assert(dependent_false<T>, "type_or_check not defined");
+            }
+        } else {
+#if PK_VERSION_MAJOR == 2
+            // for C++ type, lookup the type in the type map
+            auto type = vm->_cxx_typeid_map.try_get(typeid(T));
+            // if found, return the type
+            if(type) return *type;
+#else
+            auto result = vm->_cxx_typeid_map.find(typeid(T));
+            if(result != vm->_cxx_typeid_map.end()) { return result->second; }
+#endif
+            // if not found, raise error
+            std::string msg = "can not c++ instance cast to object, type: {";
+            msg += type_name<T>();
+            msg += "} is not registered.";
+            vm->TypeError(msg);
+            PK_UNREACHABLE();
+        }
+    }
+
+    template <typename T, typename Base = void>
+    static handle create(const handle& scope, const char* name, bool is_builtin = false) {
+        pkpy::Type type = vm->tp_object;
+#if PK_VERSION_MAJOR == 2
+        pkpy::PyTypeInfo::Vt vt = pkpy::PyTypeInfo::Vt::get<instance>();
+
+        if(is_builtin) { vt = pkpy::PyTypeInfo::Vt::get<T>(); }
+
+        if constexpr(!std::is_same_v<Base, void>) {
+            type = type_visitor::type<Base>();
+            vt = {};
+        }
+
+        handle result = vm->new_type_object(scope.ptr().get(), name, type, true, vt);
+        if(!is_builtin) { vm->_cxx_typeid_map.insert(typeid(T), result._as<pkpy::Type>()); }
+#else
+        if constexpr(!std::is_same_v<Base, void>) { type = type_visitor::type<Base>(); }
+        handle result = vm->new_type_object(scope.ptr(), name, type, true);
+        if(!is_builtin) (vm->_cxx_typeid_map.try_emplace(typeid(T), result._as<pkpy::Type>()));
+#endif
+        // set __module__
+        setattr(scope, name, result);
+        return result;
+    }
+
+    template <typename T>
+    static bool check(const handle& obj) {
+        if constexpr(is_pyobject_v<T>) {
+            if constexpr(is_type<T>) {
+                return vm->isinstance(obj.ptr(), T::type_or_check());
+            } else {
+                // some type, like iterable, iterator, they don't have according type in python
+                // but they have a function to check the type, then just call the function
+                return T::type_or_check(obj);
+            }
+        } else {
+            return vm->isinstance(obj.ptr(), type<T>());
+        }
+    }
+};
+
+// undef in pybind11.h
+#define PYBIND11_TYPE_IMPLEMENT(parent, name, tp)                                                                      \
+                                                                                                                       \
+private:                                                                                                               \
+    using underlying_type = name;                                                                                      \
+                                                                                                                       \
+    inline static auto type_or_check = [] {                                                                            \
+        return tp;                                                                                                     \
+    };                                                                                                                 \
+                                                                                                                       \
+    decltype(auto) self() const { return _as<underlying_type>(); }                                                     \
+                                                                                                                       \
+    template <typename... Args>                                                                                        \
+    static handle create(Args&&... args) {                                                                             \
+        if constexpr(pkpy::is_sso_v<underlying_type>) {                                                                \
+            return pkpy::py_var(vm, std::forward<Args>(args)...);                                                      \
+        } else {                                                                                                       \
+            return vm->heap.gcnew<underlying_type>(type_or_check(), std::forward<Args>(args)...);                      \
+        }                                                                                                              \
+    }                                                                                                                  \
+                                                                                                                       \
+    friend type_visitor;                                                                                               \
+    using parent::parent;
+
+/*=============================================================================//
+// pkpy does not use reference counts, so object is just fot API compatibility //
+//=============================================================================*/
+class object : public handle {
+    PYBIND11_TYPE_IMPLEMENT(handle, empty, vm->tp_object);
+
+public:
+    object(const handle& h) : handle(h) {
+        // object is must not null ptr
+        assert(h.ptr() != nullptr);
+    }
+};
+
+// undef after usage
+#define PYBIND11_BINARY_OPERATOR(OP, NAME)                                                                             \
+    inline object operator OP (const handle& lhs, const handle& rhs) { return handle(vm->py_op(NAME))(lhs, rhs); }
+
+#define PYBIND11_INPLACE_OPERATOR(OP, NAME)                                                                            \
+    inline object operator OP (handle& lhs, const handle& rhs) {                                                       \
+        handle result = handle(vm->py_op(NAME))(lhs, rhs);                                                             \
+        return lhs = result;                                                                                           \
+    }
+
+#define PYBIND11_BINARY_LOGIC_OPERATOR(OP, NAME)                                                                       \
+    inline bool operator OP (const handle& lhs, const handle& rhs) {                                                   \
+        return pybind11::cast<bool>(handle(vm->py_op(NAME))(lhs, rhs));                                                \
+    }
+
+PYBIND11_BINARY_OPERATOR(+, "add");
+PYBIND11_BINARY_OPERATOR(-, "sub");
+PYBIND11_BINARY_OPERATOR(*, "mul");
+PYBIND11_BINARY_OPERATOR(/, "truediv");
+PYBIND11_BINARY_OPERATOR(%, "mod");
+PYBIND11_BINARY_OPERATOR(|, "or_");
+PYBIND11_BINARY_OPERATOR(&, "and_");
+PYBIND11_BINARY_OPERATOR(^, "xor");
+PYBIND11_BINARY_OPERATOR(<<, "lshift");
+PYBIND11_BINARY_OPERATOR(>>, "rshift");
+
+PYBIND11_INPLACE_OPERATOR(+=, "iadd");
+PYBIND11_INPLACE_OPERATOR(-=, "isub");
+PYBIND11_INPLACE_OPERATOR(*=, "imul");
+PYBIND11_INPLACE_OPERATOR(/=, "itruediv");
+PYBIND11_INPLACE_OPERATOR(%=, "imod");
+PYBIND11_INPLACE_OPERATOR(|=, "ior");
+PYBIND11_INPLACE_OPERATOR(&=, "iand");
+PYBIND11_INPLACE_OPERATOR(^=, "ixor");
+PYBIND11_INPLACE_OPERATOR(<<=, "ilshift");
+PYBIND11_INPLACE_OPERATOR(>>=, "irshift");
+
+PYBIND11_BINARY_LOGIC_OPERATOR(==, "eq");
+PYBIND11_BINARY_LOGIC_OPERATOR(!=, "ne");
+PYBIND11_BINARY_LOGIC_OPERATOR(<, "lt");
+PYBIND11_BINARY_LOGIC_OPERATOR(>, "gt");
+PYBIND11_BINARY_LOGIC_OPERATOR(<=, "le");
+PYBIND11_BINARY_LOGIC_OPERATOR(>=, "ge");
+
+#undef PYBIND11_BINARY_OPERATOR
+#undef PYBIND11_INPLACE_OPERATOR
+#undef PYBIND11_BINARY_LOGIC_OPERATOR
+};  // namespace pybind11
diff --git a/include/pybind11/internal/type_traits.h b/include/pybind11/internal/type_traits.h
new file mode 100644
index 00000000..1bb17172
--- /dev/null
+++ b/include/pybind11/internal/type_traits.h
@@ -0,0 +1,170 @@
+#pragma once
+#include <tuple>
+#include <string_view>
+#include <type_traits>
+
+namespace pybind11 {
+
+template <typename T>
+constexpr bool dependent_false = false;
+
+template <typename T, typename Tuple>
+struct tuple_push_front;
+
+template <typename T, typename... Ts>
+struct tuple_push_front<T, std::tuple<Ts...>> {
+    using type = std::tuple<T, Ts...>;
+};
+
+template <typename T, typename Tuple>
+using tuple_push_front_t = typename tuple_push_front<T, Tuple>::type;
+
+// traits for function types
+template <typename Fn>
+struct function_traits {
+    static_assert(dependent_false<Fn>, "unsupported function type");
+};
+
+#define PYBIND11_FUNCTION_TRAITS_SPECIALIZE(qualifiers)                                                                \
+    template <typename R, typename... Args>                                                                            \
+    struct function_traits<R(Args...) qualifiers> {                                                                    \
+        using return_type = R;                                                                                         \
+        using args_type = std::tuple<Args...>;                                                                         \
+        constexpr static std::size_t args_count = sizeof...(Args);                                                     \
+    };
+
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE()
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(&)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(const)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(const&)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(noexcept)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(& noexcept)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(const noexcept)
+PYBIND11_FUNCTION_TRAITS_SPECIALIZE(const& noexcept)
+
+#undef PYBIND11_FUNCTION_TRAITS_SPECIALIZE
+
+template <typename T>
+using function_return_t = typename function_traits<T>::return_type;
+
+template <typename T>
+using function_args_t = typename function_traits<T>::args_type;
+
+template <typename T>
+constexpr std::size_t function_args_count = function_traits<T>::args_count;
+
+// traits for member pointers
+template <typename T>
+struct member_traits;
+
+template <typename M, typename C>
+struct member_traits<M C::*> {
+    using member_type = M;
+    using class_type = C;
+};
+
+template <typename T>
+using member_type_t = typename member_traits<T>::member_type;
+
+template <typename T>
+using class_type_t = typename member_traits<T>::class_type;
+
+// some traits for distinguishing between function pointers, member function pointers and
+// functors
+using std::is_member_function_pointer_v;
+using std::is_member_object_pointer_v;
+
+template <typename T>
+constexpr inline bool is_function_pointer_v = std::is_function_v<std::remove_pointer_t<T>>;
+
+template <typename T, typename U = void>
+constexpr bool is_functor_v = false;
+
+template <typename T>
+constexpr inline bool is_functor_v<T, std::void_t<decltype(&T::operator())>> = true;
+
+template <typename T, typename SFINAE = void>
+struct callable_traits;
+
+template <typename T>
+struct callable_traits<T, std::enable_if_t<is_member_function_pointer_v<T>>> {
+    using args_type = tuple_push_front_t<class_type_t<T>&, function_args_t<member_type_t<T>>>;
+    using return_type = function_return_t<member_type_t<T>>;
+};
+
+template <typename T>
+struct callable_traits<T, std::enable_if_t<is_function_pointer_v<T>>> {
+    using args_type = function_args_t<std::remove_pointer_t<T>>;
+    using return_type = function_return_t<std::remove_pointer_t<T>>;
+};
+
+template <typename T>
+struct callable_traits<T, std::enable_if_t<is_functor_v<T>>> {
+    using args_type = function_args_t<member_type_t<decltype(&T::operator())>>;
+    using return_type = function_return_t<member_type_t<decltype(&T::operator())>>;
+};
+
+template <typename Callable>
+using callable_args_t = typename callable_traits<Callable>::args_type;
+
+template <typename Callable>
+using callable_return_t = typename callable_traits<Callable>::return_type;
+
+template <typename Callable>
+constexpr std::size_t callable_args_count_v = std::tuple_size_v<callable_args_t<Callable>>;
+
+template <typename T>
+struct type_identity {
+    using type = T;
+};
+
+template <typename T>
+using remove_cvref_t = std::remove_cv_t<std::remove_reference_t<T>>;
+
+template <typename T, typename... Ts>
+constexpr inline std::size_t types_count_v = (std::is_same_v<T, Ts> + ...);
+
+template <typename T>
+constexpr inline std::size_t types_count_v<T> = 0;
+
+template <typename T, typename... Ts>
+constexpr inline int type_index_v = [] {
+    bool arr[sizeof...(Ts) + 1] = {std::is_same_v<T, Ts>...};
+    for(int i = 0; i < sizeof...(Ts); ++i) {
+        if(arr[i]) return i;
+    }
+    return -1;
+}();
+
+static_assert(types_count_v<int, int, float, int> == 2);
+static_assert(types_count_v<int, float, double> == 0);
+static_assert(type_index_v<int, int, float, int> == 0);
+static_assert(type_index_v<float, int, float, int> == 1);
+static_assert(type_index_v<int, float, double> == -1);
+
+template <typename T>
+constexpr inline bool is_multiple_pointer_v = std::is_pointer_v<T> && is_multiple_pointer_v<std::remove_pointer_t<T>>;
+
+template <typename T>
+using pybind11_decay_t = std::decay_t<std::remove_pointer_t<std::decay_t<T>>>;
+
+template <typename T>
+constexpr auto type_name() {
+#if __GNUC__ || __clang__
+    std::string_view name = __PRETTY_FUNCTION__;
+    std::size_t start = name.find('=') + 2;
+    std::size_t end = name.size() - 1;
+    return std::string_view{name.data() + start, end - start};
+#elif _MSC_VER
+    std::string_view name = __FUNCSIG__;
+    std::size_t start = name.find('<') + 1;
+    std::size_t end = name.rfind(">(");
+    name = std::string_view{name.data() + start, end - start};
+    start = name.find(' ');
+    return start == std::string_view::npos ? name : std::string_view{name.data() + start + 1, name.size() - start - 1};
+#else
+    static_assert(false, "Unsupported compiler");
+#endif
+}
+
+}  // namespace pybind11
diff --git a/include/pybind11/internal/types.h b/include/pybind11/internal/types.h
new file mode 100644
index 00000000..1c079ca4
--- /dev/null
+++ b/include/pybind11/internal/types.h
@@ -0,0 +1,395 @@
+#pragma once
+#include "object.h"
+
+namespace pybind11 {
+
+template <typename T>
+handle cast(T&& value, return_value_policy policy = return_value_policy::automatic_reference, handle parent = {});
+
+struct arg {
+    const char* name;
+    handle default_;
+
+    arg(const char* name) : name(name), default_() {}
+
+    template <typename T>
+    arg& operator= (T&& value) {
+        default_ = cast(std::forward<T>(value));
+        return *this;
+    }
+};
+
+// undef in pybind11.h
+#define PYBIND11_REGISTER_INIT(func)                                                                                   \
+    static inline int _register = [] {                                                                                 \
+        interpreter::register_init(func);                                                                              \
+        return 0;                                                                                                      \
+    }();
+
+class none : public object {
+#if PK_VERSION_MAJOR == 2
+    PYBIND11_TYPE_IMPLEMENT(object, empty, vm->tp_none_type);
+#else
+    PYBIND11_TYPE_IMPLEMENT(object, empty, [](const handle& obj) {
+        return obj.is_none();
+    });
+#endif
+
+public:
+    none() : object(vm->None) {}
+};
+
+/// corresponding to type in Python
+class type : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Type, vm->tp_type);
+
+public:
+    template <typename T>
+    static handle handle_of() {
+        return type_visitor::type<T>();
+    }
+
+    static type of(const handle& obj) { return type(vm->_t(obj.ptr())); }
+};
+
+/// corresponding to bool in Python
+class bool_ : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, bool, vm->tp_bool);
+
+public:
+    bool_(bool value) : object(create(value)) {}
+
+    operator bool () const { return self(); }
+};
+
+/// corresponding to int in Python
+class int_ : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::i64, vm->tp_int);
+
+public:
+    int_(int64_t value) : object(create(value)) {}
+
+    operator int64_t () const { return self(); }
+};
+
+/// corresponding to float in Python
+class float_ : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::f64, vm->tp_float);
+
+public:
+    float_(double value) : object(create(value)) {}
+
+    operator double () const { return self(); }
+};
+
+class iterable : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, empty, [](const handle& obj) {
+        return vm->getattr(obj.ptr(), pkpy::__iter__, false) != nullptr;
+    });
+};
+
+class iterator : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, empty, [](const handle& obj) {
+        return vm->getattr(obj.ptr(), pkpy::__next__, false) != nullptr &&
+               vm->getattr(obj.ptr(), pkpy::__iter__, false) != nullptr;
+    });
+
+    handle m_value;
+
+    iterator(pkpy::PyVar n, pkpy::PyVar s) : object(n), m_value(s) {}
+
+public:
+    iterator(const handle& obj) : object(obj) { m_value = vm->py_next(obj.ptr()); }
+
+    iterator operator++ () {
+        m_value = vm->py_next(m_ptr);
+        return *this;
+    }
+
+    iterator operator++ (int) {
+        m_value = vm->py_next(m_ptr);
+        return *this;
+    }
+
+    const handle& operator* () const { return m_value; }
+
+    friend bool operator== (const iterator& lhs, const iterator& rhs) { return lhs.m_value.is(rhs.m_value); }
+
+    friend bool operator!= (const iterator& lhs, const iterator& rhs) { return !(lhs == rhs); }
+
+    static iterator sentinel() { return iterator(vm->None, vm->StopIteration); }
+};
+
+class str : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Str, vm->tp_str);
+
+public:
+    str(const char* c, int len) : object(create(c, len)) {};
+
+    str(const char* c = "") : str(c, strlen(c)) {}
+
+    str(const std::string& s) : str(s.data(), s.size()) {}
+
+    str(std::string_view sv) : str(sv.data(), sv.size()) {}
+
+    // explicit str(const bytes& b);
+    explicit str(handle h);
+
+    operator std::string_view () const { return self().sv(); }
+
+    template <typename... Args>
+    str format(Args&&... args) const;
+};
+
+// class bytes : public object {
+// public:
+//     using object::object;
+// };
+
+// class bytearray : public object {
+// public:
+//     using object::object;
+// };
+
+class tuple : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Tuple, vm->tp_tuple);
+
+public:
+    tuple(int n) : object(create(n)) {}
+
+    template <typename... Args, std::enable_if_t<(sizeof...(Args) > 1)>* = nullptr>
+    tuple(Args&&... args) : object(create(sizeof...(Args))) {
+        int index = 0;
+        ((self()[index++] = pybind11::cast(std::forward<Args>(args)).ptr()), ...);
+    }
+
+    int size() const { return self().size(); }
+
+    bool empty() const { return size() == 0; }
+
+    tuple_accessor operator[] (int i) const;
+};
+
+class list : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::List, vm->tp_list)
+
+public:
+    list() : object(create(0)) {}
+
+    list(int n) : object(create(n)) {}
+
+    template <typename... Args, std::enable_if_t<(sizeof...(Args) > 1)>* = nullptr>
+    list(Args&&... args) : object(create(sizeof...(Args))) {
+        int index = 0;
+        ((self()[index++] = pybind11::cast(std::forward<Args>(args)).ptr()), ...);
+    }
+
+    int size() const { return self().size(); }
+
+    bool empty() const { return size() == 0; }
+
+    void clear() { self().clear(); }
+
+    list_accessor operator[] (int i) const;
+
+    void append(const handle& obj) { self().push_back(obj.ptr()); }
+
+    void extend(const handle& iterable) {
+        for(auto& item: iterable) {
+            append(item);
+        }
+    }
+
+    void insert(int index, const handle& obj) {
+#if PK_VERSION_MAJOR == 2
+        const auto pos = self().begin() + index;
+        self().insert(pos, obj.ptr());
+#else
+        self().insert(index, obj.ptr());
+#endif
+    }
+};
+
+class slice : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Slice, vm->tp_slice);
+
+public:
+};
+
+// class set : public object {
+// public:
+//     using object::object;
+//     // set() : object(vm->new_object<pkpy::Se>(pkpy::VM::tp_set), true) {}
+// };
+//
+
+class dict : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Dict, vm->tp_dict);
+
+public:
+#if PK_VERSION_MAJOR == 2
+    dict() : object(create()) {}
+
+    template <typename... Args, typename = std::enable_if_t<(std::is_same_v<remove_cvref_t<Args>, arg> && ...)>>
+    dict(Args&&... args) : object(create()) {
+        auto foreach_ = [&](pybind11::arg& arg) {
+            setitem(str(arg.name), arg.default_);
+        };
+        (foreach_(args), ...);
+    }
+
+    void setitem(const handle& key, const handle& value) { self().set(vm, key.ptr(), value.ptr()); }
+
+    handle getitem(const handle& key) const { return self().try_get(vm, key.ptr()); }
+
+    struct iterator {
+        pkpy_DictIter iter;
+        std::pair<handle, handle> value;
+
+        iterator operator++ () {
+            bool is_ended = pkpy_DictIter__next(&iter, (PyVar*)&value.first, (PyVar*)&value.second);
+            if(!is_ended) {
+                iter._dict = nullptr;
+                iter._index = -1;
+            }
+            return *this;
+        }
+
+        std::pair<handle, handle> operator* () const { return value; }
+
+        bool operator== (const iterator& other) const {
+            return iter._dict == other.iter._dict && iter._index == other.iter._index;
+        }
+
+        bool operator!= (const iterator& other) const { return !(*this == other); }
+    };
+
+    iterator begin() const {
+        iterator iter{self().iter(), {}};
+        ++iter;
+        return iter;
+    }
+
+    iterator end() const { return {nullptr, -1}; }
+#else
+    dict() : object(create(vm)) {}
+
+    template <typename... Args, typename = std::enable_if_t<(std::is_same_v<remove_cvref_t<Args>, arg> && ...)>>
+    dict(Args&&... args) : object(create(vm)) {
+        auto foreach_ = [&](pybind11::arg& arg) {
+            setitem(str(arg.name), arg.default_);
+        };
+        (foreach_(args), ...);
+    }
+
+    void setitem(const handle& key, const handle& value) { self().set(key.ptr(), value.ptr()); }
+
+    handle getitem(const handle& key) const { return self().try_get(key.ptr()); }
+
+    struct iterator {
+        pkpy::Dict::Item* items;
+        pkpy::Dict::ItemNode* nodes;
+        int index;
+
+        iterator operator++ () {
+            index = nodes[index].next;
+            if(index == -1) {
+                items = nullptr;
+                nodes = nullptr;
+            }
+            return *this;
+        }
+
+        std::pair<handle, handle> operator* () const { return {items[index].first, items[index].second}; }
+
+        bool operator== (const iterator& other) const {
+            return items == other.items && nodes == other.nodes && index == other.index;
+        }
+
+        bool operator!= (const iterator& other) const { return !(*this == other); }
+    };
+
+    iterator begin() const {
+        auto index = self()._head_idx;
+        if(index == -1) {
+            return end();
+        } else {
+            return {self()._items, self()._nodes, index};
+        }
+    }
+
+    iterator end() const { return {nullptr, nullptr, -1}; }
+
+    template <typename Key>
+    bool contains(Key&& key) const {
+        return self().contains(vm, pybind11::cast(std::forward<Key>(key)).ptr());
+    }
+#endif
+
+    int size() const { return self().size(); }
+
+    bool empty() const { return size() == 0; }
+
+    void clear() { self().clear(); }
+
+    dict_accessor operator[] (int index) const;
+    dict_accessor operator[] (std::string_view) const;
+    dict_accessor operator[] (const handle& key) const;
+};
+
+class function : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Function, vm->tp_function);
+};
+
+//
+// class buffer : public object {
+// public:
+//    using object::object;
+//};
+//
+// class memory_view : public object {
+// public:
+//    using object::object;
+//};
+//
+class capsule : public object {
+    PYBIND11_REGISTER_INIT([] {
+        type_visitor::create<impl::capsule>(vm->builtins, "capsule", true);
+    });
+
+    PYBIND11_TYPE_IMPLEMENT(object, impl::capsule, handle(vm->builtins->attr("capsule"))._as<pkpy::Type>());
+
+public:
+    template <typename T>
+    capsule(T&& value) : object(create(std::forward<T>(value))) {}
+
+    template <typename T>
+    T& cast() const {
+        return *static_cast<T*>(self().ptr);
+    }
+};
+
+class property : public object {
+    PYBIND11_TYPE_IMPLEMENT(object, pkpy::Property, vm->tp_property);
+
+public:
+#if PK_VERSION_MAJOR == 2
+    property(handle getter, handle setter) : object(create(getter.ptr(), setter.ptr())) {}
+#else
+    property(handle getter, handle setter) : object(create(pkpy::Property{getter.ptr(), setter.ptr()})) {}
+#endif
+
+    handle getter() const { return self().getter; }
+
+    handle setter() const { return self().setter; }
+};
+
+class args : public tuple {
+    PYBIND11_TYPE_IMPLEMENT(tuple, struct empty, vm->tp_tuple);
+};
+
+class kwargs : public dict {
+    PYBIND11_TYPE_IMPLEMENT(dict, struct empty, vm->tp_dict);
+};
+
+}  // namespace pybind11
diff --git a/include/pybind11/operators.h b/include/pybind11/operators.h
new file mode 100644
index 00000000..c34920b1
--- /dev/null
+++ b/include/pybind11/operators.h
@@ -0,0 +1,201 @@
+#pragma once
+#include "pybind11.h"
+
+namespace pybind11::impl {
+
+enum op_id : int {
+    op_add,
+    op_sub,
+    op_mul,
+    op_div,
+    op_mod,
+    op_divmod,
+    op_pow,
+    op_lshift,
+    op_rshift,
+    op_and,
+    op_xor,
+    op_or,
+    op_neg,
+    op_pos,
+    op_abs,
+    op_invert,
+    op_int,
+    op_long,
+    op_float,
+    op_str,
+    op_cmp,
+    op_gt,
+    op_ge,
+    op_lt,
+    op_le,
+    op_eq,
+    op_ne,
+    op_iadd,
+    op_isub,
+    op_imul,
+    op_idiv,
+    op_imod,
+    op_ilshift,
+    op_irshift,
+    op_iand,
+    op_ixor,
+    op_ior,
+    op_complex,
+    op_bool,
+    op_nonzero,
+    op_repr,
+    op_truediv,
+    op_itruediv,
+    op_hash
+};
+
+enum op_type : int {
+    op_l, /* base type on left */
+    op_r, /* base type on right */
+    op_u  /* unary operator */
+};
+
+struct self_t {};
+
+const static self_t self = self_t();
+
+/// Type for an unused type slot
+struct undefined_t {};
+
+/// Don't warn about an unused variable
+inline self_t __self() { return self; }
+
+/// base template of operator implementations
+template <op_id, op_type, typename B, typename L, typename R>
+struct op_impl {};
+
+/// Operator implementation generator
+template <op_id id, op_type ot, typename L, typename R>
+struct op_ {
+    constexpr static bool op_enable_if_hook = true;
+
+    template <typename Class, typename... Extra>
+    void execute(Class& cl, const Extra&... extra) const {
+        using Base = typename Class::underlying_type;
+        using L_type = std::conditional_t<std::is_same<L, self_t>::value, Base, L>;
+        using R_type = std::conditional_t<std::is_same<R, self_t>::value, Base, R>;
+        using op = op_impl<id, ot, Base, L_type, R_type>;
+        cl.def(op::name(), &op::execute, extra...);
+    }
+
+    template <typename Class, typename... Extra>
+    void execute_cast(Class& cl, const Extra&... extra) const {
+        using Base = typename Class::type;
+        using L_type = std::conditional_t<std::is_same<L, self_t>::value, Base, L>;
+        using R_type = std::conditional_t<std::is_same<R, self_t>::value, Base, R>;
+        using op = op_impl<id, ot, Base, L_type, R_type>;
+        cl.def(op::name(), &op::execute_cast, extra...);
+    }
+};
+
+#define PYBIND11_BINARY_OPERATOR(id, rid, op, expr)                                                                    \
+    template <typename B, typename L, typename R>                                                                      \
+    struct op_impl<op_##id, op_l, B, L, R> {                                                                           \
+        static char const* name() { return "__" #id "__"; }                                                            \
+        static auto execute(const L& l, const R& r) -> decltype(expr) { return (expr); }                               \
+        static B execute_cast(const L& l, const R& r) { return B(expr); }                                              \
+    };                                                                                                                 \
+                                                                                                                       \
+    template <typename B, typename L, typename R>                                                                      \
+    struct op_impl<op_##id, op_r, B, L, R> {                                                                           \
+        static char const* name() { return "__" #rid "__"; }                                                           \
+        static auto execute(const R& r, const L& l) -> decltype(expr) { return (expr); }                               \
+        static B execute_cast(const R& r, const L& l) { return B(expr); }                                              \
+    };                                                                                                                 \
+                                                                                                                       \
+    inline op_<op_##id, op_l, self_t, self_t> op(const self_t&, const self_t&) {                                       \
+        return op_<op_##id, op_l, self_t, self_t>();                                                                   \
+    }                                                                                                                  \
+                                                                                                                       \
+    template <typename T>                                                                                              \
+    op_<op_##id, op_l, self_t, T> op(const self_t&, const T&) {                                                        \
+        return op_<op_##id, op_l, self_t, T>();                                                                        \
+    }                                                                                                                  \
+                                                                                                                       \
+    template <typename T>                                                                                              \
+    op_<op_##id, op_r, T, self_t> op(const T&, const self_t&) {                                                        \
+        return op_<op_##id, op_r, T, self_t>();                                                                        \
+    }
+
+#define PYBIND11_INPLACE_OPERATOR(id, op, expr)                                                                        \
+    template <typename B, typename L, typename R>                                                                      \
+    struct op_impl<op_##id, op_l, B, L, R> {                                                                           \
+        static char const* name() { return "__" #id "__"; }                                                            \
+        static auto execute(L& l, const R& r) -> decltype(expr) { return expr; }                                       \
+        static B execute_cast(L& l, const R& r) { return B(expr); }                                                    \
+    };                                                                                                                 \
+                                                                                                                       \
+    template <typename T>                                                                                              \
+    op_<op_##id, op_l, self_t, T> op(const self_t&, const T&) {                                                        \
+        return op_<op_##id, op_l, self_t, T>();                                                                        \
+    }
+
+#define PYBIND11_UNARY_OPERATOR(id, op, expr)                                                                          \
+    template <typename B, typename L>                                                                                  \
+    struct op_impl<op_##id, op_u, B, L, undefined_t> {                                                                 \
+        static char const* name() { return "__" #id "__"; }                                                            \
+        static auto execute(const L& l) -> decltype(expr) { return expr; }                                             \
+        static B execute_cast(const L& l) { return B(expr); }                                                          \
+    };                                                                                                                 \
+                                                                                                                       \
+    inline op_<op_##id, op_u, self_t, undefined_t> op(const self_t&) {                                                 \
+        return op_<op_##id, op_u, self_t, undefined_t>();                                                              \
+    }
+
+PYBIND11_BINARY_OPERATOR(sub, rsub, operator-, l - r)
+PYBIND11_BINARY_OPERATOR(add, radd, operator+, l + r)
+PYBIND11_BINARY_OPERATOR(mul, rmul, operator*, l* r)
+PYBIND11_BINARY_OPERATOR(truediv, rtruediv, operator/, l / r)
+PYBIND11_BINARY_OPERATOR(mod, rmod, operator%, l % r)
+PYBIND11_BINARY_OPERATOR(lshift, rlshift, operator<<, l << r)
+PYBIND11_BINARY_OPERATOR(rshift, rrshift, operator>>, l >> r)
+PYBIND11_BINARY_OPERATOR(and, rand, operator&, l& r)
+PYBIND11_BINARY_OPERATOR(xor, rxor, operator^, l ^ r)
+PYBIND11_BINARY_OPERATOR(eq, eq, operator==, l == r)
+PYBIND11_BINARY_OPERATOR(ne, ne, operator!=, l != r)
+PYBIND11_BINARY_OPERATOR(or, ror, operator|, l | r)
+PYBIND11_BINARY_OPERATOR(gt, lt, operator>, l > r)
+PYBIND11_BINARY_OPERATOR(ge, le, operator>=, l >= r)
+PYBIND11_BINARY_OPERATOR(lt, gt, operator<, l < r)
+PYBIND11_BINARY_OPERATOR(le, ge, operator<=, l <= r)
+// PYBIND11_BINARY_OPERATOR(pow,       rpow,         pow,          std::pow(l,  r))
+PYBIND11_INPLACE_OPERATOR(iadd, operator+=, l += r)
+PYBIND11_INPLACE_OPERATOR(isub, operator-=, l -= r)
+PYBIND11_INPLACE_OPERATOR(imul, operator*=, l *= r)
+PYBIND11_INPLACE_OPERATOR(itruediv, operator/=, l /= r)
+PYBIND11_INPLACE_OPERATOR(imod, operator%=, l %= r)
+PYBIND11_INPLACE_OPERATOR(ilshift, operator<<=, l <<= r)
+PYBIND11_INPLACE_OPERATOR(irshift, operator>>=, l >>= r)
+PYBIND11_INPLACE_OPERATOR(iand, operator&=, l &= r)
+PYBIND11_INPLACE_OPERATOR(ixor, operator^=, l ^= r)
+PYBIND11_INPLACE_OPERATOR(ior, operator|=, l |= r)
+
+PYBIND11_UNARY_OPERATOR(neg, operator-, -l)
+PYBIND11_UNARY_OPERATOR(pos, operator+, +l)
+
+// WARNING: This usage of `abs` should only be done for existing STL overloads.
+// Adding overloads directly in to the `std::` namespace is advised against:
+// https://en.cppreference.com/w/cpp/language/extending_std
+
+// PYBIND11_UNARY_OPERATOR(abs, abs, std::abs(l))
+// PYBIND11_UNARY_OPERATOR(hash, hash, std::hash<L>()(l))
+// PYBIND11_UNARY_OPERATOR(invert, operator~, (~l))
+// PYBIND11_UNARY_OPERATOR(bool, operator!, !!l)
+// PYBIND11_UNARY_OPERATOR(int, int_, (int)l)
+// PYBIND11_UNARY_OPERATOR(float, float_, (double)l)
+
+#undef PYBIND11_BINARY_OPERATOR
+#undef PYBIND11_INPLACE_OPERATOR
+#undef PYBIND11_UNARY_OPERATOR
+
+}  // namespace pybind11::impl
+
+namespace pybind11 {
+using impl::self;
+}
diff --git a/include/pybind11/pybind11.h b/include/pybind11/pybind11.h
new file mode 100644
index 00000000..f0424576
--- /dev/null
+++ b/include/pybind11/pybind11.h
@@ -0,0 +1,21 @@
+#pragma once
+#include "internal/class.h"
+
+namespace pybind11 {
+
+namespace literals {
+inline arg operator""_a (const char* c, size_t) { return arg(c); }
+}  // namespace literals
+
+struct scoped_interpreter {
+    scoped_interpreter() { interpreter::initialize(); }
+
+    ~scoped_interpreter() { interpreter::finalize(); }
+};
+
+}  // namespace pybind11
+
+// namespace pybind11
+
+#undef PYBIND11_TYPE_IMPLEMENT
+#undef PYBIND11_REGISTER_INIT
diff --git a/include/pybind11/stl.h b/include/pybind11/stl.h
new file mode 100644
index 00000000..10e8e976
--- /dev/null
+++ b/include/pybind11/stl.h
@@ -0,0 +1,144 @@
+#include "pybind11.h"
+
+#include <array>
+#include <vector>
+#include <list>
+#include <deque>
+#include <forward_list>
+
+#include <map>
+#include <unordered_map>
+
+namespace pybind11 {
+
+template <typename T, std::size_t N>
+struct type_caster<std::array<T, N>> {
+
+    struct wrapper {
+        std::array<T, N> container = {};
+
+        operator std::array<T, N>&& () { return std::move(container); }
+    };
+
+    wrapper value;
+
+    bool load(const handle& src, bool convert) {
+        if(!isinstance<list>(src)) { return false; }
+        auto list = src.cast<pybind11::list>();
+
+        if(list.size() != N) { return false; }
+
+        for(std::size_t i = 0; i < N; ++i) {
+            type_caster<T> caster;
+            if(!caster.load(list[i], convert)) { return false; }
+            value.container[i] = caster.value;
+        }
+
+        return true;
+    }
+
+    template <typename U>
+    static handle cast(U&& src, return_value_policy policy, handle parent) {
+        auto list = pybind11::list();
+        for(auto& item: src) {
+            list.append(pybind11::cast(item, policy, parent));
+        }
+        return list;
+    }
+};
+
+template <typename T>
+constexpr bool is_py_list_like_v = false;
+
+template <typename T, typename Allocator>
+constexpr bool is_py_list_like_v<std::vector<T, Allocator>> = true;
+
+template <typename T, typename Allocator>
+constexpr bool is_py_list_like_v<std::list<T, Allocator>> = true;
+
+template <typename T, typename Allocator>
+constexpr bool is_py_list_like_v<std::deque<T, Allocator>> = true;
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_py_list_like_v<T>>> {
+
+    struct wrapper {
+        T container;
+
+        operator T&& () { return std::move(container); }
+    };
+
+    wrapper value;
+
+    bool load(const handle& src, bool convert) {
+        if(!isinstance<list>(src)) { return false; }
+        auto list = src.cast<pybind11::list>();
+
+        for(auto item: list) {
+            type_caster<typename T::value_type> caster;
+            if(!caster.load(item, convert)) { return false; }
+            value.container.push_back(caster.value);
+        }
+
+        return true;
+    }
+
+    template <typename U>
+    static handle cast(U&& src, return_value_policy policy, handle parent) {
+        auto list = pybind11::list();
+        for(auto& item: src) {
+            list.append(pybind11::cast(item, policy, parent));
+        }
+        return list;
+    }
+};
+
+template <typename T>
+constexpr bool is_py_map_like_v = false;
+
+template <typename Key, typename T, typename Compare, typename Allocator>
+constexpr bool is_py_map_like_v<std::map<Key, T, Compare, Allocator>> = true;
+
+template <typename Key, typename T, typename Hash, typename KeyEqual, typename Allocator>
+constexpr bool is_py_map_like_v<std::unordered_map<Key, T, Hash, KeyEqual, Allocator>> = true;
+
+template <typename T>
+struct type_caster<T, std::enable_if_t<is_py_map_like_v<T>>> {
+
+    struct wrapper {
+        T container;
+
+        operator T&& () { return std::move(container); }
+    };
+
+    wrapper value;
+
+    bool load(const handle& src, bool convert) {
+        if(!isinstance<dict>(src)) { return false; }
+        auto dict = src.cast<pybind11::dict>();
+
+        for(auto item: dict) {
+            type_caster<typename T::key_type> key_caster;
+            if(!key_caster.load(item.first, convert)) { return false; }
+
+            type_caster<typename T::mapped_type> value_caster;
+            if(!value_caster.load(item.second, convert)) { return false; }
+
+            value.container.try_emplace(key_caster.value, value_caster.value);
+        }
+
+        return true;
+    }
+
+    template <typename U>
+    static handle cast(U&& src, return_value_policy policy, handle parent) {
+        auto dict = pybind11::dict();
+        for(auto& [key, value]: src) {
+            dict[pybind11::cast(key, policy, parent)] = pybind11::cast(value, policy, parent);
+        }
+        return dict;
+    }
+};
+
+}  // namespace pybind11
+