Add ReferenceWrapper

include/utempl/reference_wrapper.hpp

@@ -0,0 +1,41 @@
+#pragma once
+
+namespace utempl {
+template <typename T>
+struct ReferenceWrapper;
+
+template <typename T>
+struct ReferenceWrapper<T&&> {
+  inline constexpr auto operator*() -> T& {
+    return this->value;
+  };
+  inline constexpr auto operator->() -> T* {
+    return &this->value;
+  };
+  T&& value;
+};
+
+template <typename T>
+struct ReferenceWrapper<const T&> {
+  inline constexpr auto operator*() -> const T& {
+    return this->value;
+  };
+  inline constexpr auto operator->() -> const T* {
+    return &this->value;
+  };
+  const T& value;
+};
+
+template <typename T>
+struct ReferenceWrapper<T&> {
+
+  inline constexpr auto operator*() -> T& {
+    return this->value;
+  };
+  inline constexpr auto operator->() -> T* {
+    return &this->value;
+  };
+  T& value;
+};
+
+} // namespace utempl