1 files changed, 508 insertions, 508 deletions
diff --git a/asl/option.hpp b/asl/option.hpp
index f7a3eab..d12d4ce 100644
--- a/asl/option.hpp
+++ b/asl/option.hpp
@@ -1,509 +1,509 @@
-#pragma once
-
-#include "asl/assert.hpp"
-#include "asl/meta.hpp"
-#include "asl/maybe_uninit.hpp"
-#include "asl/functional.hpp"
-#include "asl/annotations.hpp"
-#include "asl/hash.hpp"
-
-namespace asl
-{
-
-struct nullopt_t {};
-static constexpr nullopt_t nullopt{};
-
-// @Todo(option) Reference
-// @Todo(option) Function
-// @Todo(option) Arrays
-
-template<is_object T> class option;
-
-namespace option_internal
-{
-
-template<typename T, typename U>
-concept not_constructible_from_option = 
-    !constructible_from<T, option<U>&> &&
-    !constructible_from<T, const option<U>&> &&
-    !constructible_from<T, option<U>&&> &&
-    !constructible_from<T, const option<U>&&>;
-
-template<typename T, typename U>
-concept not_assignable_from_option = 
-    !assignable_from<T&, option<U>&> &&
-    !assignable_from<T&, const option<U>&> &&
-    !assignable_from<T&, option<U>&&> &&
-    !assignable_from<T&, const option<U>&&>;
-
-template<typename T, typename U>
-concept not_constructible_assignable_from_option =
-    not_constructible_from_option<T, U> &&
-    not_assignable_from_option<T, U>;
-
-} // namespace option_internal
-
-template<typename T>
-concept is_option = requires
-{
-    typename T::type;
-    requires same_as<un_cvref_t<T>, option<typename T::type>>;
-};
-
-template<is_object T>
-class option
-{
-    static constexpr bool kHasNiche = has_niche<T>;
-
-    using HasValueMarker = select_t<kHasNiche, empty, bool>;
-
-    maybe_uninit<T> m_payload{};
-    ASL_NO_UNIQUE_ADDRESS HasValueMarker m_has_value{};
-
-    template<is_object U>
-    friend class option;
-
-    template<typename... Args>
-    constexpr void construct(Args&&... args)
-    {
-        ASL_ASSERT(!has_value());
-
-        if constexpr (!kHasNiche)
-        {
-            m_payload.construct_unsafe(ASL_FWD(args)...);
-            m_has_value = true;
-        }
-        else
-        {
-            if constexpr (move_assignable<T>)
-            {
-                m_payload.assign_unsafe(ASL_MOVE(T{ASL_FWD(args)...}));
-            }
-            else
-            {
-                m_payload.destroy_unsafe();
-                m_payload.construct_unsafe(ASL_FWD(args)...);
-            }
-        }
-    }
-
-    template<typename U>
-    constexpr void assign(U&& arg)
-    {
-        ASL_ASSERT(has_value());
-        m_payload.assign_unsafe(ASL_FWD(arg));
-    }
-
-public:
-    using type = T;
-
-    constexpr option() : option{nullopt} {}
-    
-     // NOLINTNEXTLINE(*-explicit-conversions)
-    constexpr option(nullopt_t) requires (!kHasNiche) {}
-    
-     // NOLINTNEXTLINE(*-explicit-conversions)
-    constexpr option(nullopt_t) requires kHasNiche : m_payload{in_place, niche_t{}} {}
-
-    template<typename U = T>
-    constexpr explicit (!convertible_from<T, U&&>)
-    option(U&& value)
-        requires (
-            kHasNiche &&
-            constructible_from<T, U&&> &&
-            !same_as<un_cvref_t<U>, option>
-        )
-        : m_payload{in_place, ASL_FWD(value)}
-    {}
-
-    template<typename U = T>
-    constexpr explicit (!convertible_from<T, U&&>)        
-    option(U&& value)
-        requires (
-            !kHasNiche &&
-            constructible_from<T, U&&> &&
-            !is_option<U>
-        )
-        : m_payload{in_place, ASL_FWD(value)}
-        , m_has_value{true}
-    {}
-    
-    constexpr option(const option& other) requires trivially_copy_constructible<T> = default;
-    constexpr option(const option& other) requires (!copy_constructible<T>) = delete;
-
-    constexpr option(const option& other)    
-        requires copy_constructible<T> && (!trivially_copy_constructible<T>)
-        : option{nullopt}
-    {
-        if (other.has_value())
-        {
-            construct(other.m_payload.as_init_unsafe());
-        }
-    }
-    
-    constexpr option(option&& other) requires trivially_move_constructible<T> = default;
-    constexpr option(option&& other) requires (!move_constructible<T>) = delete;
-
-    constexpr option(option&& other)    
-        requires move_constructible<T> && (!trivially_move_constructible<T>)
-        : option{nullopt}
-    {
-        if (other.has_value())
-        {
-            construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
-        }
-    }
-
-    template<typename U>
-    constexpr explicit (!convertible_from<T, const U&>)
-    option(const option<U>& other)
-        requires (
-            constructible_from<T, const U&> && 
-            option_internal::not_constructible_from_option<T, U>
-        )
-        : option{nullopt}
-    {
-        if (other.has_value())
-        {
-            construct(other.m_payload.as_init_unsafe());
-        }
-    }
-
-    template<typename U>
-    constexpr explicit (!convertible_from<T, U&&>)
-    option(option<U>&& other)
-        requires (
-            constructible_from<T, U&&> &&
-            option_internal::not_constructible_from_option<T, U>
-        )
-        : option{nullopt}
-    {
-        if (other.has_value())
-        {
-            construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
-        }
-    }
-
-    constexpr option& operator=(nullopt_t) &
-    {
-        reset();
-        return *this;
-    }
-
-    template<typename U = T>
-    constexpr option& operator=(U&& value) &
-        requires (
-            assignable_from<T&, U&&> &&
-            constructible_from<T, U&&> && 
-            !is_option<U>
-        )
-    {
-        if (has_value())
-        {
-            assign(ASL_FWD(value));
-        }
-        else
-        {
-            construct(ASL_FWD(value));
-        }
-
-        return *this;
-    }
-
-    constexpr option& operator=(const option& other) &
-        requires (!copy_assignable<T>) = delete;
-        
-    constexpr option& operator=(const option& other) &
-        requires trivially_copy_assignable<T> = default;
-
-    constexpr option& operator=(const option& other) &
-        requires copy_assignable<T> && (!trivially_copy_constructible<T>)
-    {
-        if (&other == this) { return *this; }
-
-        if (other.has_value())
-        {
-            if (has_value())
-            {
-                assign(other.m_payload.as_init_unsafe());
-            }
-            else
-            {
-                construct(other.m_payload.as_init_unsafe());
-            }
-        }
-        else if (has_value())
-        {
-            reset();
-        }
-        
-        return *this;
-    }
-    
-    constexpr option& operator=(option&& other) &
-        requires (!move_assignable<T>) = delete;
-        
-    constexpr option& operator=(option&& other) &
-        requires trivially_move_assignable<T> = default;
-
-    constexpr option& operator=(option&& other) &
-        requires move_assignable<T> && (!trivially_move_constructible<T>)
-    {
-        if (&other == this) { return *this; }
-
-        if (other.has_value())
-        {
-            if (has_value())
-            {
-                assign(ASL_MOVE(other.m_payload.as_init_unsafe()));
-            }
-            else
-            {
-                construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
-            }
-        }
-        else if (has_value())
-        {
-            reset();
-        }
-        
-        return *this;
-    }
-
-    template<typename U = T>
-    constexpr option& operator=(const option<U>& other) &
-        requires (
-            constructible_from<T, const U&> &&
-            assignable_from<T&, const U&> &&
+#pragma once
+
+#include "asl/assert.hpp"
+#include "asl/meta.hpp"
+#include "asl/maybe_uninit.hpp"
+#include "asl/functional.hpp"
+#include "asl/annotations.hpp"
+#include "asl/hash.hpp"
+
+namespace asl
+{
+
+struct nullopt_t {};
+static constexpr nullopt_t nullopt{};
+
+// @Todo(option) Reference
+// @Todo(option) Function
+// @Todo(option) Arrays
+
+template<is_object T> class option;
+
+namespace option_internal
+{
+
+template<typename T, typename U>
+concept not_constructible_from_option =
+    !constructible_from<T, option<U>&> &&
+    !constructible_from<T, const option<U>&> &&
+    !constructible_from<T, option<U>&&> &&
+    !constructible_from<T, const option<U>&&>;
+
+template<typename T, typename U>
+concept not_assignable_from_option =
+    !assignable_from<T&, option<U>&> &&
+    !assignable_from<T&, const option<U>&> &&
+    !assignable_from<T&, option<U>&&> &&
+    !assignable_from<T&, const option<U>&&>;
+
+template<typename T, typename U>
+concept not_constructible_assignable_from_option =
+    not_constructible_from_option<T, U> &&
+    not_assignable_from_option<T, U>;
+
+} // namespace option_internal
+
+template<typename T>
+concept is_option = requires
+{
+    typename T::type;
+    requires same_as<un_cvref_t<T>, option<typename T::type>>;
+};
+
+template<is_object T>
+class option
+{
+    static constexpr bool kHasNiche = has_niche<T>;
+
+    using HasValueMarker = select_t<kHasNiche, empty, bool>;
+
+    maybe_uninit<T> m_payload{};
+    ASL_NO_UNIQUE_ADDRESS HasValueMarker m_has_value{};
+
+    template<is_object U>
+    friend class option;
+
+    template<typename... Args>
+    constexpr void construct(Args&&... args)
+    {
+        ASL_ASSERT(!has_value());
+
+        if constexpr (!kHasNiche)
+        {
+            m_payload.construct_unsafe(ASL_FWD(args)...);
+            m_has_value = true;
+        }
+        else
+        {
+            if constexpr (move_assignable<T>)
+            {
+                m_payload.assign_unsafe(ASL_MOVE(T{ASL_FWD(args)...}));
+            }
+            else
+            {
+                m_payload.destroy_unsafe();
+                m_payload.construct_unsafe(ASL_FWD(args)...);
+            }
+        }
+    }
+
+    template<typename U>
+    constexpr void assign(U&& arg)
+    {
+        ASL_ASSERT(has_value());
+        m_payload.assign_unsafe(ASL_FWD(arg));
+    }
+
+public:
+    using type = T;
+
+    constexpr option() : option{nullopt} {}
+
+     // NOLINTNEXTLINE(*-explicit-conversions)
+    constexpr option(nullopt_t) requires (!kHasNiche) {}
+
+     // NOLINTNEXTLINE(*-explicit-conversions)
+    constexpr option(nullopt_t) requires kHasNiche : m_payload{in_place, niche_t{}} {}
+
+    template<typename U = T>
+    constexpr explicit (!convertible_from<T, U&&>)
+    option(U&& value)
+        requires (
+            kHasNiche &&
+            constructible_from<T, U&&> &&
+            !same_as<un_cvref_t<U>, option>
+        )
+        : m_payload{in_place, ASL_FWD(value)}
+    {}
+
+    template<typename U = T>
+    constexpr explicit (!convertible_from<T, U&&>)
+    option(U&& value)
+        requires (
+            !kHasNiche &&
+            constructible_from<T, U&&> &&
+            !is_option<U>
+        )
+        : m_payload{in_place, ASL_FWD(value)}
+        , m_has_value{true}
+    {}
+
+    constexpr option(const option& other) requires trivially_copy_constructible<T> = default;
+    constexpr option(const option& other) requires (!copy_constructible<T>) = delete;
+
+    constexpr option(const option& other)
+        requires copy_constructible<T> && (!trivially_copy_constructible<T>)
+        : option{nullopt}
+    {
+        if (other.has_value())
+        {
+            construct(other.m_payload.as_init_unsafe());
+        }
+    }
+
+    constexpr option(option&& other) requires trivially_move_constructible<T> = default;
+    constexpr option(option&& other) requires (!move_constructible<T>) = delete;
+
+    constexpr option(option&& other)
+        requires move_constructible<T> && (!trivially_move_constructible<T>)
+        : option{nullopt}
+    {
+        if (other.has_value())
+        {
+            construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
+        }
+    }
+
+    template<typename U>
+    constexpr explicit (!convertible_from<T, const U&>)
+    option(const option<U>& other)
+        requires (
+            constructible_from<T, const U&> &&
+            option_internal::not_constructible_from_option<T, U>
+        )
+        : option{nullopt}
+    {
+        if (other.has_value())
+        {
+            construct(other.m_payload.as_init_unsafe());
+        }
+    }
+
+    template<typename U>
+    constexpr explicit (!convertible_from<T, U&&>)
+    option(option<U>&& other)
+        requires (
+            constructible_from<T, U&&> &&
+            option_internal::not_constructible_from_option<T, U>
+        )
+        : option{nullopt}
+    {
+        if (other.has_value())
+        {
+            construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
+        }
+    }
+
+    constexpr option& operator=(nullopt_t) &
+    {
+        reset();
+        return *this;
+    }
+
+    template<typename U = T>
+    constexpr option& operator=(U&& value) &
+        requires (
+            assignable_from<T&, U&&> &&
+            constructible_from<T, U&&> &&
+            !is_option<U>
+        )
+    {
+        if (has_value())
+        {
+            assign(ASL_FWD(value));
+        }
+        else
+        {
+            construct(ASL_FWD(value));
+        }
+
+        return *this;
+    }
+
+    constexpr option& operator=(const option& other) &
+        requires (!copy_assignable<T>) = delete;
+
+    constexpr option& operator=(const option& other) &
+        requires trivially_copy_assignable<T> = default;
+
+    constexpr option& operator=(const option& other) &
+        requires copy_assignable<T> && (!trivially_copy_constructible<T>)
+    {
+        if (&other == this) { return *this; }
+
+        if (other.has_value())
+        {
+            if (has_value())
+            {
+                assign(other.m_payload.as_init_unsafe());
+            }
+            else
+            {
+                construct(other.m_payload.as_init_unsafe());
+            }
+        }
+        else if (has_value())
+        {
+            reset();
+        }
+
+        return *this;
+    }
+
+    constexpr option& operator=(option&& other) &
+        requires (!move_assignable<T>) = delete;
+
+    constexpr option& operator=(option&& other) &
+        requires trivially_move_assignable<T> = default;
+
+    constexpr option& operator=(option&& other) &
+        requires move_assignable<T> && (!trivially_move_constructible<T>)
+    {
+        if (&other == this) { return *this; }
+
+        if (other.has_value())
+        {
+            if (has_value())
+            {
+                assign(ASL_MOVE(other.m_payload.as_init_unsafe()));
+            }
+            else
+            {
+                construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
+            }
+        }
+        else if (has_value())
+        {
+            reset();
+        }
+
+        return *this;
+    }
+
+    template<typename U = T>
+    constexpr option& operator=(const option<U>& other) &
+        requires (
+            constructible_from<T, const U&> &&
+            assignable_from<T&, const U&> &&
             option_internal::not_constructible_assignable_from_option<T, U>
-        )
-    {
-        if (other.has_value())
-        {
-            if (has_value())
-            {
-                assign(other.m_payload.as_init_unsafe());
-            }
-            else
-            {
-                construct(other.m_payload.as_init_unsafe());
-            }
-        }
-        else if (has_value())
-        {
-            reset();
-        }
-
-        return *this;
-    }
-    
-    template<typename U = T>
-    constexpr option& operator=(option<U>&& other) &
-        requires (
-            constructible_from<T, U&&> &&
-            assignable_from<T&, U&&> &&
-            option_internal::not_constructible_assignable_from_option<T, U>
-        )
-    {
-        if (other.has_value())
-        {
-            if (has_value())
-            {
-                assign(ASL_MOVE(other.m_payload.as_init_unsafe()));
-            }
-            else
-            {
-                construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
-            }
-        }
-        else if (has_value())
-        {
-            reset();
-        }
-
-        return *this;
-    }
-       
-    constexpr ~option() requires trivially_destructible<T> = default;
-    constexpr ~option() requires (!trivially_destructible<T>)
-    {
-        reset();
-    }
-
-    constexpr void reset()
-    {
-        if (!has_value()) { return; }
-        
-        if constexpr (kHasNiche)
-        {
-            if constexpr (move_assignable<T>)
-            {
-                m_payload.assign_unsafe(ASL_MOVE(T{niche_t{}}));
-            }
-            else
-            {
-                m_payload.destroy_unsafe();
-                m_payload.construct_unsafe(niche_t{});
-            }
-        }
-        else
-        {
-            m_has_value = false;
-            m_payload.destroy_unsafe();
-        }
-    }
-
-    constexpr bool has_value() const
-    {
-        if constexpr (kHasNiche)
-        {
-            return m_payload.as_init_unsafe() != niche_t{};
-        }
-        else
-        {
-            return m_has_value;
-        }
-    }
-
-    // @Todo(C++23) Deducing this
-    constexpr T&& value() &&
-    {
-        ASL_ASSERT_RELEASE(has_value());
-        return ASL_MOVE(m_payload).as_init_unsafe();
-    }
-
-    constexpr T& value() &
-    {
-        ASL_ASSERT_RELEASE(has_value());
-        return m_payload.as_init_unsafe();
-    }
-
-    constexpr const T& value() const&
-    {
-        ASL_ASSERT_RELEASE(has_value());
-        return m_payload.as_init_unsafe();
-    }
-
-    template<typename U>
-    constexpr T value_or(U&& other_value) const&
-        requires copy_constructible<T> && convertible_from<T, U&&>
-    {
-        return has_value() ? value() : static_cast<T>(ASL_FWD(other_value));
-    }
-
-    template<typename U>
-    constexpr T value_or(U&& other_value) &&
-        requires move_constructible<T> && convertible_from<T, U&&>
-    {
-        return has_value() ? ASL_MOVE(value()) : static_cast<T>(ASL_FWD(other_value));
-    }
-
-    template<typename... Args>
-    constexpr T& emplace(Args&&... args) &
-        requires constructible_from<T, Args&&...>
-    {
-        if (has_value()) { reset(); }
-        construct(ASL_FWD(args)...);
-        return value();
-    }
-
-    template<typename F>
-    constexpr auto and_then(F&& f) &
-        requires is_option<result_of_t<F(T&)>>
-    {
-        if (has_value())
-        {
-            return invoke(ASL_FWD(f), value());
-        }
-        return un_cvref_t<result_of_t<F(T&)>>{};
-    }
-
-    template<typename F>
-    constexpr auto and_then(F&& f) const&
-        requires is_option<result_of_t<F(const T&)>>
-    {
-        if (has_value())
-        {
-            return invoke(ASL_FWD(f), value());
-        }
-        return un_cvref_t<result_of_t<F(const T&)>>{};
-    }
-
-    template<typename F>
-    constexpr auto and_then(F&& f) &&
-        requires is_option<result_of_t<F(T)>>
-    {
-        if (has_value())
-        {
-            return invoke(ASL_FWD(f), ASL_MOVE(value()));
-        }
-        return un_cvref_t<result_of_t<F(T)>>{};
-    }
-
-    template<typename F>
-    constexpr auto transform(F&& f) &
-    {
-        using U = un_cvref_t<result_of_t<F(T&)>>;
-        if (has_value())
-        {
-            return option<U>{ invoke(ASL_FWD(f), value()) };
-        }
-        return option<U>{};
-    }
-
-    template<typename F>
-    constexpr auto transform(F&& f) const&
-    {
-        using U = un_cvref_t<result_of_t<F(const T&)>>;
-        if (has_value())
-        {
-            return option<U>{ invoke(ASL_FWD(f), value()) };
-        }
-        return option<U>{};
-    }
-
-    template<typename F>
-    constexpr auto transform(F&& f) &&
-    {
-        using U = un_cvref_t<result_of_t<F(T)>>;
-        if (has_value())
-        {
-            return option<U>{ invoke(ASL_FWD(f), ASL_MOVE(value())) };
-        }
-        return option<U>{};
-    }
-
-    template<typename F>
-    constexpr option or_else(F&& f) const&
-        requires same_as<un_cvref_t<result_of_t<F()>>, option>
-    {
-        return has_value() ? *this : invoke(ASL_FWD(f));
-    }
-
-    template<typename F>
-    constexpr option or_else(F&& f) &&
-        requires same_as<un_cvref_t<result_of_t<F()>>, option>
-    {
-        return has_value() ? ASL_MOVE(*this) : invoke(ASL_FWD(f));
-    }
-
-    template<typename H>
-    requires (!uniquely_represented<option>) && hashable<T>
-    friend H AslHashValue(H h, const option& opt)
-    {
-        if (!opt.has_value())
-        {
-            return H::combine(ASL_MOVE(h), 0);
-        }
-        return H::combine(ASL_MOVE(h), 1, opt.value());
-    }
-};
-
-template<typename T>
-requires has_niche<T> && uniquely_represented<T>
-struct is_uniquely_represented<option<T>> : true_type {};
-
-template<typename T>
-option(T) -> option<T>;
-
-} // namespace asl
+        )
+    {
+        if (other.has_value())
+        {
+            if (has_value())
+            {
+                assign(other.m_payload.as_init_unsafe());
+            }
+            else
+            {
+                construct(other.m_payload.as_init_unsafe());
+            }
+        }
+        else if (has_value())
+        {
+            reset();
+        }
+
+        return *this;
+    }
+
+    template<typename U = T>
+    constexpr option& operator=(option<U>&& other) &
+        requires (
+            constructible_from<T, U&&> &&
+            assignable_from<T&, U&&> &&
+            option_internal::not_constructible_assignable_from_option<T, U>
+        )
+    {
+        if (other.has_value())
+        {
+            if (has_value())
+            {
+                assign(ASL_MOVE(other.m_payload.as_init_unsafe()));
+            }
+            else
+            {
+                construct(ASL_MOVE(other.m_payload.as_init_unsafe()));
+            }
+        }
+        else if (has_value())
+        {
+            reset();
+        }
+
+        return *this;
+    }
+
+    constexpr ~option() requires trivially_destructible<T> = default;
+    constexpr ~option() requires (!trivially_destructible<T>)
+    {
+        reset();
+    }
+
+    constexpr void reset()
+    {
+        if (!has_value()) { return; }
+
+        if constexpr (kHasNiche)
+        {
+            if constexpr (move_assignable<T>)
+            {
+                m_payload.assign_unsafe(ASL_MOVE(T{niche_t{}}));
+            }
+            else
+            {
+                m_payload.destroy_unsafe();
+                m_payload.construct_unsafe(niche_t{});
+            }
+        }
+        else
+        {
+            m_has_value = false;
+            m_payload.destroy_unsafe();
+        }
+    }
+
+    constexpr bool has_value() const
+    {
+        if constexpr (kHasNiche)
+        {
+            return m_payload.as_init_unsafe() != niche_t{};
+        }
+        else
+        {
+            return m_has_value;
+        }
+    }
+
+    // @Todo(C++23) Deducing this
+    constexpr T&& value() &&
+    {
+        ASL_ASSERT_RELEASE(has_value());
+        return ASL_MOVE(m_payload).as_init_unsafe();
+    }
+
+    constexpr T& value() &
+    {
+        ASL_ASSERT_RELEASE(has_value());
+        return m_payload.as_init_unsafe();
+    }
+
+    constexpr const T& value() const&
+    {
+        ASL_ASSERT_RELEASE(has_value());
+        return m_payload.as_init_unsafe();
+    }
+
+    template<typename U>
+    constexpr T value_or(U&& other_value) const&
+        requires copy_constructible<T> && convertible_from<T, U&&>
+    {
+        return has_value() ? value() : static_cast<T>(ASL_FWD(other_value));
+    }
+
+    template<typename U>
+    constexpr T value_or(U&& other_value) &&
+        requires move_constructible<T> && convertible_from<T, U&&>
+    {
+        return has_value() ? ASL_MOVE(value()) : static_cast<T>(ASL_FWD(other_value));
+    }
+
+    template<typename... Args>
+    constexpr T& emplace(Args&&... args) &
+        requires constructible_from<T, Args&&...>
+    {
+        if (has_value()) { reset(); }
+        construct(ASL_FWD(args)...);
+        return value();
+    }
+
+    template<typename F>
+    constexpr auto and_then(F&& f) &
+        requires is_option<result_of_t<F(T&)>>
+    {
+        if (has_value())
+        {
+            return invoke(ASL_FWD(f), value());
+        }
+        return un_cvref_t<result_of_t<F(T&)>>{};
+    }
+
+    template<typename F>
+    constexpr auto and_then(F&& f) const&
+        requires is_option<result_of_t<F(const T&)>>
+    {
+        if (has_value())
+        {
+            return invoke(ASL_FWD(f), value());
+        }
+        return un_cvref_t<result_of_t<F(const T&)>>{};
+    }
+
+    template<typename F>
+    constexpr auto and_then(F&& f) &&
+        requires is_option<result_of_t<F(T)>>
+    {
+        if (has_value())
+        {
+            return invoke(ASL_FWD(f), ASL_MOVE(value()));
+        }
+        return un_cvref_t<result_of_t<F(T)>>{};
+    }
+
+    template<typename F>
+    constexpr auto transform(F&& f) &
+    {
+        using U = un_cvref_t<result_of_t<F(T&)>>;
+        if (has_value())
+        {
+            return option<U>{ invoke(ASL_FWD(f), value()) };
+        }
+        return option<U>{};
+    }
+
+    template<typename F>
+    constexpr auto transform(F&& f) const&
+    {
+        using U = un_cvref_t<result_of_t<F(const T&)>>;
+        if (has_value())
+        {
+            return option<U>{ invoke(ASL_FWD(f), value()) };
+        }
+        return option<U>{};
+    }
+
+    template<typename F>
+    constexpr auto transform(F&& f) &&
+    {
+        using U = un_cvref_t<result_of_t<F(T)>>;
+        if (has_value())
+        {
+            return option<U>{ invoke(ASL_FWD(f), ASL_MOVE(value())) };
+        }
+        return option<U>{};
+    }
+
+    template<typename F>
+    constexpr option or_else(F&& f) const&
+        requires same_as<un_cvref_t<result_of_t<F()>>, option>
+    {
+        return has_value() ? *this : invoke(ASL_FWD(f));
+    }
+
+    template<typename F>
+    constexpr option or_else(F&& f) &&
+        requires same_as<un_cvref_t<result_of_t<F()>>, option>
+    {
+        return has_value() ? ASL_MOVE(*this) : invoke(ASL_FWD(f));
+    }
+
+    template<typename H>
+    requires (!uniquely_represented<option>) && hashable<T>
+    friend H AslHashValue(H h, const option& opt)
+    {
+        if (!opt.has_value())
+        {
+            return H::combine(ASL_MOVE(h), 0);
+        }
+        return H::combine(ASL_MOVE(h), 1, opt.value());
+    }
+};
+
+template<typename T>
+requires has_niche<T> && uniquely_represented<T>
+struct is_uniquely_represented<option<T>> : true_type {};
+
+template<typename T>
+option(T) -> option<T>;
+
+} // namespace asl