From 4fa6821e0645ff61a9380cd090abff472205c630 Mon Sep 17 00:00:00 2001
From: Lexi Winter <lexi@le-fay.org>
Date: Sun, 29 Jun 2025 17:16:22 +0100
Subject: add clang-tidy support

---
 nihil.generator/manual_lifetime.ccm | 117 ++++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 nihil.generator/manual_lifetime.ccm

(limited to 'nihil.generator/manual_lifetime.ccm')

diff --git a/nihil.generator/manual_lifetime.ccm b/nihil.generator/manual_lifetime.ccm
new file mode 100644
index 0000000..d249e99
--- /dev/null
+++ b/nihil.generator/manual_lifetime.ccm
@@ -0,0 +1,117 @@
+///////////////////////////////////////////////////////////////////////////////
+// Reference implementation of std::generator proposal P2168.
+//
+// See https://wg21.link/P2168 for details.
+//
+///////////////////////////////////////////////////////////////////////////////
+// Copyright Lewis Baker, Corentin Jabot
+//
+// Use, modification and distribution is subject to the Boost Software License,
+// Version 1.0.
+// (See accompanying file LICENSE or http://www.boost.org/LICENSE_1_0.txt)
+///////////////////////////////////////////////////////////////////////////////
+
+module;
+
+#include <concepts>
+#include <memory>
+
+export module nihil.generator:manual_lifetime;
+
+namespace nihil {
+
+template <typename T>
+struct manual_lifetime {
+	manual_lifetime() noexcept {}
+	~manual_lifetime() {}
+
+	template <typename ...Args>
+	auto construct(this manual_lifetime &self, Args && ...args)
+		noexcept(std::is_nothrow_constructible_v<T, Args...>)
+		-> T &
+	{
+		return *::new (static_cast<void*>(std::addressof(self.m_value)))
+			T(static_cast<Args &&>(args)...);
+	}
+
+	void destruct(this manual_lifetime &self)
+		noexcept(std::is_nothrow_destructible_v<T>)
+	{
+		self.m_value.~T();
+	}
+
+	auto get(this manual_lifetime &self) noexcept -> T &
+	{
+		return self.m_value;
+	}
+
+	auto get(this manual_lifetime &&self) noexcept -> T &&
+	{
+		return static_cast<T&&>(self.m_value);
+	}
+
+	auto get(this manual_lifetime const &self) noexcept -> T const &
+	{
+		return self.m_value;
+	}
+
+	auto get(this manual_lifetime const &&self) noexcept -> T const &&
+	{
+		return static_cast<T const &&>(self.m_value);
+	}
+
+private:
+	union {
+		std::remove_const_t<T> m_value;
+	};
+};
+
+template <typename T>
+class manual_lifetime<T &> {
+	manual_lifetime() noexcept {}
+	~manual_lifetime() {}
+
+	auto construct(this manual_lifetime &self, T &value) noexcept -> T &
+	{
+		self.m_value = std::addressof(value);
+		return self.m_value;
+	}
+
+	auto destruct(this manual_lifetime &) noexcept -> void
+	{
+	}
+
+	auto get(this manual_lifetime const &self) noexcept -> T &
+	{
+		return *self.m_value;
+	}
+
+private:
+	T *m_value = nullptr;
+};
+
+template <typename T>
+class manual_lifetime<T &&> {
+	manual_lifetime() noexcept {}
+	~manual_lifetime() {}
+
+	auto construct(this manual_lifetime &self, T &&value) noexcept -> T &&
+	{
+		self.m_value = std::addressof(value);
+		return static_cast<T &&>(value);
+	}
+
+	void destruct(this manual_lifetime &) noexcept
+	{
+	}
+
+	auto get(this manual_lifetime const &self) noexcept -> T &&
+	{
+		return static_cast<T &&>(*self.m_value);
+	}
+
+private:
+	T* m_value = nullptr;
+};
+
+}
-- 
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