1 files changed, 26 insertions, 0 deletions
diff --git a/src/kernel/NeKit/Nullable.h b/src/kernel/NeKit/Nullable.h
new file mode 100644
index 00000000..c17009fc
--- /dev/null
+++ b/src/kernel/NeKit/Nullable.h
@@ -0,0 +1,26 @@
+#ifndef __NE_KIT_NULLABLE_H__
+#define __NE_KIT_NULLABLE_H__
+
+#include <NeKit/Config.h>
+
+namespace Kernel {
+template <class Type>
+struct IsDefined final {
+  using ResultType    = Type;
+  using ResultTypeRef = Type&;
+
+  static constexpr bool kValue = true;
+};
+
+template <>
+struct IsDefined<nullPtr> final {
+  static constexpr bool kValue = false;
+};
+
+template <class Type>
+concept IsAcceptable = requires() {
+  { IsDefined<Type>::kValue };
+};
+}  // namespace Kernel
+
+#endif  // !__NE_KIT_NULLABLE_H__
+\ No newline at end of file