Add strong type macro

modules/core/inc/tactile/core/misc/strong_type.hpp

@@ -0,0 +1,17 @@
+// Copyright (C) 2023 Albin Johansson (GNU General Public License v3.0)
+
+#pragma once
+
+#include <compare>  // strong_ordering
+
+/**
+ * \brief Simple macro useful for defining simple (but effective) strong types.
+ */
+#define TACTILE_STRONG_TYPE(Name, UnderlyingType)                            \
+  struct Name final {                                                        \
+    UnderlyingType value;                                                    \
+                                                                             \
+    constexpr auto operator==(const Name&) const noexcept -> bool = default; \
+    constexpr auto operator<=>(const Name&) const noexcept                   \
+        -> std::strong_ordering = default;                                   \
+  }

modules/core/test/misc/strong_type_test.cpp

@@ -0,0 +1,43 @@
+// Copyright (C) 2023 Albin Johansson (GNU General Public License v3.0)
+
+#include "tactile/core/misc/strong_type.hpp"
+
+#include <gtest/gtest.h>
+
+#include "tactile/core/container/string.hpp"
+
+namespace {
+
+TACTILE_STRONG_TYPE(StrongInt, int);
+TACTILE_STRONG_TYPE(StrongStr, tactile::String);
+
+}  // namespace
+
+TEST(StrongType, DefaultValue)
+{
+  const StrongInt integer {};
+  const StrongStr string {};
+
+  EXPECT_EQ(integer.value, 0);
+  EXPECT_EQ(string.value, "");
+}
+
+TEST(StrongType, EqualityComparison)
+{
+  const StrongStr s1 {"foo"};
+  const StrongStr s2 {"bar"};
+
+  EXPECT_EQ(s1, s1);
+  EXPECT_EQ(s2, s2);
+  EXPECT_NE(s1, s2);
+}
+
+TEST(StrongType, SpaceshipComparison)
+{
+  const StrongInt i1 {-413};
+  const StrongInt i2 {382};
+
+  EXPECT_EQ(i1 <=> i1, std::strong_ordering::equal);
+  EXPECT_EQ(i1 <=> i2, std::strong_ordering::less);
+  EXPECT_EQ(i2 <=> i1, std::strong_ordering::greater);
+}