From c04383b471f04f0b4a90ea11ed1b0dc8186302d1 Mon Sep 17 00:00:00 2001
From: Brett <brettmaster1@gmail.com>
Date: Sat, 26 Apr 2025 16:35:56 -0400
Subject: [PATCH] tested concrete types. everything works

---
 CMakeLists.txt              |  2 +-
 include/blt/meta/function.h | 73 +++++++++++++++--------------
 tests/variant_tests.cpp     | 91 +++++++++++++++++++++++++++++++++++++
 3 files changed, 128 insertions(+), 38 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 78add7b..93b5f95 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.20)
 include(cmake/color.cmake)
-set(BLT_VERSION 5.4.13)
+set(BLT_VERSION 5.4.14)
 
 set(BLT_TARGET BLT)
 
diff --git a/include/blt/meta/function.h b/include/blt/meta/function.h
index e71e680..0c09fc4 100644
--- a/include/blt/meta/function.h
+++ b/include/blt/meta/function.h
@@ -99,48 +99,47 @@ namespace blt::meta
 		using class_type = Class;
 	};
 
+	template <typename>
+	struct lambda_traits
+	{};
+
+	template <typename Return, typename Class, typename... Args>
+	struct lambda_traits<Return (Class::*)(Args...) const>
+	{
+		using return_type = Return;
+		using args_tuple = std::tuple<Args...>;
+		using class_type = Class;
+	};
+
+	template <typename Return, typename Class, typename... Args>
+	struct lambda_traits<Return (Class::*)(Args...) noexcept>
+	{
+		using return_type = Return;
+		using args_tuple = std::tuple<Args...>;
+		using class_type = Class;
+	};
+
+	template <typename Return, typename Class, typename... Args>
+	struct lambda_traits<Return (Class::*)(Args...) const noexcept>
+	{
+		using return_type = Return;
+		using args_tuple = std::tuple<Args...>;
+		using class_type = Class;
+	};
+
+	template <typename Return, typename Class, typename... Args>
+	struct lambda_traits<Return (Class::*)(Args...)>
+	{
+		using return_type = Return;
+		using args_tuple = std::tuple<Args...>;
+		using class_type = Class;
+	};
+
 	template <typename Func>
 	struct function_like
 	{
 	private:
-		template <typename>
-		struct lambda_traits
-		{};
-
-		template <typename Return, typename Class, typename... Args>
-		struct lambda_traits<Return (Class::*)(Args...) const>
-		{
-			using return_type = Return;
-			using args_tuple = std::tuple<Args...>;
-			using class_type = Class;
-		};
-
-		template <typename Return, typename Class, typename... Args>
-		struct lambda_traits<Return (Class::*)(Args...) noexcept>
-		{
-			using return_type = Return;
-			using args_tuple = std::tuple<Args...>;
-			using class_type = Class;
-		};
-
-		template <typename Return, typename Class, typename... Args>
-		struct lambda_traits<Return (Class::*)(Args...) const noexcept>
-		{
-			using return_type = Return;
-			using args_tuple = std::tuple<Args...>;
-			using class_type = Class;
-		};
-
-		template <typename Return, typename Class, typename... Args>
-		struct lambda_traits<Return (Class::*)(Args...)>
-		{
-			using return_type = Return;
-			using args_tuple = std::tuple<Args...>;
-			using class_type = Class;
-		};
-
 		using lambda_trait = lambda_traits<decltype(&std::decay_t<Func>::operator())>;
-
 	public:
 		using tag_type = lambda_tag;
 		using return_type = typename lambda_trait::return_type;
diff --git a/tests/variant_tests.cpp b/tests/variant_tests.cpp
index 67b62eb..7d3e2c5 100644
--- a/tests/variant_tests.cpp
+++ b/tests/variant_tests.cpp
@@ -122,6 +122,76 @@ struct no_members
 	int hello;
 };
 
+struct concrete_visitor
+{
+	[[nodiscard]] std::string operator()(const type1& t1) const
+	{
+		return t1.to_string();
+	}
+
+	[[nodiscard]] std::string operator()(const type2& t2) const
+	{
+		return t2.to_string();
+	}
+
+	[[nodiscard]] std::string operator()(const type3& t3) const
+	{
+		return t3.to_string();
+	}
+};
+
+struct concrete_visitor_with_state
+{
+	concrete_visitor_with_state(std::function<std::string(const type1&)> func1, std::function<std::string(const type2&)> func2,
+								std::function<std::string(const type3&)> func3): func1(std::move(func1)), func2(std::move(func2)),
+																				func3(std::move(func3))
+	{}
+
+	[[nodiscard]] std::string operator()(const type1& t1) const
+	{
+		return func1(t1);
+	}
+
+	[[nodiscard]] std::string operator()(const type2& t2) const
+	{
+		return func2(t2);
+	}
+
+	[[nodiscard]] std::string operator()(const type3& t3) const
+	{
+		return func3(t3);
+	}
+
+private:
+	std::function<std::string(const type1&)> func1;
+	std::function<std::string(const type2&)> func2;
+	std::function<std::string(const type3&)> func3;
+};
+
+/*
+ * **********
+ * This is not allowed! BLT's visitor is only able to change return types if you provide functions as lambdas,
+ * otherwise it is not possible to change the return of these functions
+ * **********
+ */
+struct concrete_void
+{
+	[[nodiscard]] std::string operator()(const type1& t1) const
+	{
+		return t1.to_string();
+	}
+
+	[[nodiscard]] std::string operator()(const type2& t2) const
+	{
+		return t2.to_string();
+	}
+
+	void operator()(const type3&) const
+	{
+
+	}
+};
+
 int main()
 {
 	blt::variant_t<type1, type2, type3> v1{type1{}};
@@ -221,5 +291,26 @@ int main()
 	BLT_ASSERT(provided_visitor == type3{}.to_string());
 	BLT_TRACE("Provided visitor: {}", provided_visitor);
 
+	concrete_visitor visit{};
+	auto concrete_visitor_result = v3.visit(visit);
+	BLT_TRACE("Concrete Result: {}", concrete_visitor_result);
+	BLT_ASSERT(concrete_visitor_result == type3{}.to_string());
+
+	auto concrete_visitor_result2 = v2.visit(visit);
+	BLT_TRACE("Concrete Result: {}", concrete_visitor_result2);
+	BLT_ASSERT(concrete_visitor_result2 == type2{}.to_string());
+
+	concrete_visitor_with_state concrete_visitor_state{[](const auto& type) {
+		return type.to_string();
+	}, [](const auto& type) {
+		return type.to_string();
+	}, [](const auto& type) {
+		return type.to_string();
+	}};
+
+	auto concrete_visitor_state_result = v1.visit(blt::black_box_ret(concrete_visitor_state));
+	BLT_TRACE("Concrete State Result: {}", concrete_visitor_state_result);
+	BLT_ASSERT(concrete_visitor_state_result == type1{}.to_string());
+
 	BLT_INFO("Variant tests passed!");
 }