From eee954d396a9fd6c3de3a5c9108d48322bbeb626 Mon Sep 17 00:00:00 2001
From: Chris Thrasher <chrisjthrasher@gmail.com>
Date: Thu, 25 May 2023 11:08:14 -0600
Subject: [PATCH] Add `rsl::Type`

---
 include/rsl/type.hpp | 24 ++++++++++++++++++++++++
 tests/CMakeLists.txt |  3 ++-
 tests/type.cpp       | 26 ++++++++++++++++++++++++++
 3 files changed, 52 insertions(+), 1 deletion(-)
 create mode 100644 include/rsl/type.hpp
 create mode 100644 tests/type.cpp

diff --git a/include/rsl/type.hpp b/include/rsl/type.hpp
new file mode 100644
index 0000000..79d2251
--- /dev/null
+++ b/include/rsl/type.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+namespace rsl {
+
+/** @file */
+
+/**
+ * @brief Class template for creating strong type aliases
+ *
+ * @tparam T value type
+ * @tparam Tag Tag type to diambiguate separate type aliases
+ */
+template <typename T, typename Tag>
+class Type {
+    T value_;
+
+   public:
+    constexpr explicit Type(const T& value) : value_(value) {}
+    [[nodiscard]] constexpr T& get() { return value_; }
+    [[nodiscard]] constexpr const T& get() const { return value_; }
+    [[nodiscard]] constexpr explicit operator T() const { return value_; }
+};
+
+}  // namespace rsl
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index d575a9f..5cc4d84 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -14,7 +14,8 @@ add_executable(test-rsl
     random.cpp
     static_string.cpp
     static_vector.cpp
-    try.cpp)
+    try.cpp
+    type.cpp)
 target_link_libraries(test-rsl PRIVATE
     rsl::rsl
     Catch2::Catch2WithMain
diff --git a/tests/type.cpp b/tests/type.cpp
new file mode 100644
index 0000000..5563200
--- /dev/null
+++ b/tests/type.cpp
@@ -0,0 +1,26 @@
+#include <rsl/type.hpp>
+
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("rsl::Type") {
+    using StrongInt = rsl::Type<int, struct StrongIntTag>; // For testing constexpr support
+    using StrongString = rsl::Type<std::string, struct StringStringTag>; // For testing non-constexpr types
+
+    SECTION("Construction") {
+        constexpr auto strong_int = StrongInt(42);
+        STATIC_CHECK(strong_int.get() == 42);
+        STATIC_CHECK(int{strong_int} == 42);
+        STATIC_CHECK(int(strong_int) == 42);
+
+        auto const strong_string = StrongString("abcdefg");
+        CHECK(strong_string.get() == "abcdefg");
+        CHECK(std::string{strong_string} == "abcdefg");
+        CHECK(std::string(strong_string) == "abcdefg");
+    }
+
+    SECTION("get()") {
+        auto strong_int = StrongInt(1337);
+        strong_int.get() = 100;
+        CHECK(strong_int.get() == 100);
+    }
+}