fb7f8f194c
Notes * Due to the limitations for how Boxed_Value is handled the unique_ptrs must still be wrapped in a shared_ptr * However, this caveat does not directly affect the user
309 lines
9.4 KiB
C++
309 lines
9.4 KiB
C++
// This file is distributed under the BSD License.
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// See "license.txt" for details.
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// Copyright 2009-2012, Jonathan Turner (jonathan@emptycrate.com)
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// Copyright 2009-2016, Jason Turner (jason@emptycrate.com)
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// http://www.chaiscript.com
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#ifndef CHAISCRIPT_BOXED_CAST_HELPER_HPP_
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#define CHAISCRIPT_BOXED_CAST_HELPER_HPP_
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#include <memory>
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#include <type_traits>
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#include "boxed_value.hpp"
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#include "type_info.hpp"
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namespace chaiscript
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{
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class Type_Conversions_State;
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namespace detail
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{
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// Cast_Helper_Inner helper classes
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template<typename T>
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T* throw_if_null(T *t)
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{
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if (t) { return t; }
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throw std::runtime_error("Attempted to dereference null Boxed_Value");
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}
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template<typename T>
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static const T *verify_type_no_throw(const Boxed_Value &ob, const std::type_info &ti, const T *ptr) {
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if (ob.get_type_info() == ti) {
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return ptr;
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} else {
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throw chaiscript::detail::exception::bad_any_cast();
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}
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}
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template<typename T>
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static T *verify_type_no_throw(const Boxed_Value &ob, const std::type_info &ti, T *ptr) {
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if (!ob.is_const() && ob.get_type_info() == ti) {
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return ptr;
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} else {
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throw chaiscript::detail::exception::bad_any_cast();
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}
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}
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template<typename T>
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static const T *verify_type(const Boxed_Value &ob, const std::type_info &ti, const T *ptr) {
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if (ob.get_type_info().bare_equal_type_info(ti)) {
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return throw_if_null(ptr);
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} else {
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throw chaiscript::detail::exception::bad_any_cast();
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}
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}
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template<typename T>
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static T *verify_type(const Boxed_Value &ob, const std::type_info &ti, T *ptr) {
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if (!ob.is_const() && ob.get_type_info().bare_equal_type_info(ti)) {
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return throw_if_null(ptr);
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} else {
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throw chaiscript::detail::exception::bad_any_cast();
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}
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}
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/// Generic Cast_Helper_Inner, for casting to any type
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template<typename Result>
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struct Cast_Helper_Inner
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{
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static Result cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return *static_cast<const Result *>(verify_type(ob, typeid(Result), ob.get_const_ptr()));
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}
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};
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template<typename Result>
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struct Cast_Helper_Inner<const Result> : Cast_Helper_Inner<Result>
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{
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};
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/// Cast_Helper_Inner for casting to a const * type
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template<typename Result>
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struct Cast_Helper_Inner<const Result *>
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{
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static const Result * cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return static_cast<const Result *>(verify_type_no_throw(ob, typeid(Result), ob.get_const_ptr()));
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}
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};
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/// Cast_Helper_Inner for casting to a * type
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template<typename Result>
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struct Cast_Helper_Inner<Result *>
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{
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static Result * cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return static_cast<Result *>(verify_type_no_throw(ob, typeid(Result), ob.get_ptr()));
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}
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};
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template<typename Result>
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struct Cast_Helper_Inner<Result * const &> : public Cast_Helper_Inner<Result *>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const Result * const &> : public Cast_Helper_Inner<const Result *>
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{
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};
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/// Cast_Helper_Inner for casting to a & type
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template<typename Result>
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struct Cast_Helper_Inner<const Result &>
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{
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static const Result & cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return *static_cast<const Result *>(verify_type(ob, typeid(Result), ob.get_const_ptr()));
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}
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};
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/// Cast_Helper_Inner for casting to a & type
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template<typename Result>
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struct Cast_Helper_Inner<Result &>
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{
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static Result& cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return *static_cast<Result *>(verify_type(ob, typeid(Result), ob.get_ptr()));
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}
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};
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/// Cast_Helper_Inner for casting to a && type
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template<typename Result>
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struct Cast_Helper_Inner<Result &&>
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{
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static Result&& cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return std::move(*static_cast<Result *>(verify_type(ob, typeid(Result), ob.get_ptr())));
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}
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};
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/// Cast_Helper_Inner for casting to a std::unique_ptr<> && type
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/// \todo Fix the fact that this has to be in a shared_ptr for now
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template<typename Result>
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struct Cast_Helper_Inner<std::unique_ptr<Result> &&>
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{
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static std::unique_ptr<Result> &&cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return std::move(*(ob.get().cast<std::shared_ptr<std::unique_ptr<Result>>>()));
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}
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};
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/// Cast_Helper_Inner for casting to a std::unique_ptr<> & type
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/// \todo Fix the fact that this has to be in a shared_ptr for now
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template<typename Result>
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struct Cast_Helper_Inner<std::unique_ptr<Result> &>
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{
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static std::unique_ptr<Result> &cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return *(ob.get().cast<std::shared_ptr<std::unique_ptr<Result>>>());
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}
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};
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/// Cast_Helper_Inner for casting to a std::shared_ptr<> type
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template<typename Result>
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struct Cast_Helper_Inner<std::shared_ptr<Result> >
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{
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static auto cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return ob.get().cast<std::shared_ptr<Result> >();
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}
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};
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/// Cast_Helper_Inner for casting to a std::shared_ptr<const> type
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template<typename Result>
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struct Cast_Helper_Inner<std::shared_ptr<const Result> >
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{
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static auto cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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if (!ob.get_type_info().is_const())
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{
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return std::const_pointer_cast<const Result>(ob.get().cast<std::shared_ptr<Result> >());
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} else {
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return ob.get().cast<std::shared_ptr<const Result> >();
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}
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}
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};
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/// Cast_Helper_Inner for casting to a const std::shared_ptr<> & type
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template<typename Result>
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struct Cast_Helper_Inner<const std::shared_ptr<Result> > : Cast_Helper_Inner<std::shared_ptr<Result> >
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::shared_ptr<Result> &> : Cast_Helper_Inner<std::shared_ptr<Result> >
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<std::shared_ptr<Result> &>
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{
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static_assert(!std::is_const<Result>::value, "Non-const reference to std::shared_ptr<const T> is not supported");
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static auto cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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std::shared_ptr<Result> &res = ob.get().cast<std::shared_ptr<Result> >();
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return ob.pointer_sentinel(res);
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}
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};
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/// Cast_Helper_Inner for casting to a const std::shared_ptr<const> & type
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template<typename Result>
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struct Cast_Helper_Inner<const std::shared_ptr<const Result> > : Cast_Helper_Inner<std::shared_ptr<const Result> >
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::shared_ptr<const Result> &> : Cast_Helper_Inner<std::shared_ptr<const Result> >
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{
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};
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/// Cast_Helper_Inner for casting to a Boxed_Value type
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template<>
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struct Cast_Helper_Inner<Boxed_Value>
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{
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static Boxed_Value cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return ob;
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}
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};
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/// Cast_Helper_Inner for casting to a Boxed_Value & type
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template<>
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struct Cast_Helper_Inner<Boxed_Value &>
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{
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static std::reference_wrapper<Boxed_Value> cast(const Boxed_Value &ob, const Type_Conversions_State *)
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{
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return std::ref(const_cast<Boxed_Value &>(ob));
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}
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};
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/// Cast_Helper_Inner for casting to a const Boxed_Value & type
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template<>
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struct Cast_Helper_Inner<const Boxed_Value> : Cast_Helper_Inner<Boxed_Value>
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{
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};
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template<>
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struct Cast_Helper_Inner<const Boxed_Value &> : Cast_Helper_Inner<Boxed_Value>
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{
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};
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/// Cast_Helper_Inner for casting to a std::reference_wrapper type
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template<typename Result>
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struct Cast_Helper_Inner<std::reference_wrapper<Result> > : Cast_Helper_Inner<Result &>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::reference_wrapper<Result> > : Cast_Helper_Inner<Result &>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::reference_wrapper<Result> &> : Cast_Helper_Inner<Result &>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<std::reference_wrapper<const Result> > : Cast_Helper_Inner<const Result &>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::reference_wrapper<const Result> > : Cast_Helper_Inner<const Result &>
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{
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};
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template<typename Result>
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struct Cast_Helper_Inner<const std::reference_wrapper<const Result> & > : Cast_Helper_Inner<const Result &>
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{
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};
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/// The exposed Cast_Helper object that by default just calls the Cast_Helper_Inner
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template<typename T>
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struct Cast_Helper
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{
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static decltype(auto) cast(const Boxed_Value &ob, const Type_Conversions_State *t_conversions)
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{
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return(Cast_Helper_Inner<T>::cast(ob, t_conversions));
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}
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};
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}
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}
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#endif
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