diff --git a/sprout/breed/detail/as_lvalue.hpp b/sprout/breed/detail/as_lvalue.hpp
new file mode 100644
index 00000000..3a3e2357
--- /dev/null
+++ b/sprout/breed/detail/as_lvalue.hpp
@@ -0,0 +1,22 @@
+#ifndef SPROUT_BREED_DETAIL_AS_LVALUE_HPP
+#define SPROUT_BREED_DETAIL_AS_LVALUE_HPP
+
+#include <sprout/config.hpp>
+#include <sprout/breed/breed_fwd.hpp>
+
+namespace sprout {
+	namespace breed {
+		namespace detail {
+			template<typename T>
+			SPROUT_CONSTEXPR T& as_lvalue(T& t) {
+				return t;
+			}
+			template<typename T>
+			SPROUT_CONSTEXPR T const& as_lvalue(T const& t) {
+				return t;
+			}
+		}	// namespace detail
+	}	// namespace breed
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_BREED_DETAIL_AS_LVALUE_HPP
diff --git a/sprout/breed/detail/poly_function.hpp b/sprout/breed/detail/poly_function.hpp
new file mode 100644
index 00000000..8df3f908
--- /dev/null
+++ b/sprout/breed/detail/poly_function.hpp
@@ -0,0 +1,207 @@
+#ifndef SPROUT_BREED_DETAIL_POLY_FUNCTION_HPP
+#define SPROUT_BREED_DETAIL_POLY_FUNCTION_HPP
+
+#include <type_traits>
+#include <sprout/config.hpp>
+#include <sprout/breed/breed_fwd.hpp>
+
+namespace sprout {
+	namespace breed {
+		namespace detail {
+			template<typename T>
+			struct normalize_arg {
+			public:
+				typedef T type;
+				typedef T const& reference;
+			};
+			template<typename T>
+			struct normalize_arg<T&> {
+			public:
+				typedef T type;
+				typedef T const& reference;
+			};
+			template<typename T>
+			struct normalize_arg<T const&> {
+			public:
+				typedef T type;
+				typedef T const& reference;
+			};
+
+			template<typename T>
+			struct arg {
+			public:
+				typedef T const& type;
+			private:
+				type value;
+			public:
+				SPROUT_CONSTEXPR arg(type t)
+					: value(t)
+				{}
+				SPROUT_CONSTEXPR operator type() const {
+					return this->value;
+				}
+				SPROUT_CONSTEXPR type operator()() const {
+					return *this;
+				}
+			private:
+				arg& operator=(arg const&) = delete;
+			};
+			template<typename T>
+			struct arg<T&> {
+			public:
+				typedef T& type;
+			private:
+				type value;
+			public:
+				SPROUT_CONSTEXPR arg(type t)
+					: value(t)
+				{}
+				SPROUT_CONSTEXPR operator type() const {
+					return this->value;
+				}
+				SPROUT_CONSTEXPR type operator()() const {
+					return *this;
+				}
+			private:
+				arg& operator=(arg const&) = delete;
+			};
+
+			template<typename T, typename Void = void>
+			struct is_poly_function
+				: public std::false_type
+			{};
+			template<typename T>
+			struct is_poly_function<T, typename T::is_poly_function_base_>
+				: public std::true_type
+			{};
+
+#			define SPROUT_BREED_POLY_FUNCTION() \
+			typedef void is_poly_function_base_;
+
+			struct poly_function_base {
+			public:
+				SPROUT_BREED_POLY_FUNCTION();
+			};
+
+			template<typename Derived, typename NullaryResult = void>
+			struct poly_function
+				: public psprout::breed::detail::poly_function_base
+			{
+			public:
+				template<typename Sig>
+				struct result;
+				template<typename This>
+				struct result<This()>
+					: public Derived::template impl<>
+				{
+				public:
+					typedef typename result::result_type type;
+				};
+				template<typename This, typename... Args>
+				struct result<This(Args...)>
+					: public Derived::template impl<
+						typename normalize_arg<Args>::type...
+					>
+				{
+				public:
+					typedef typename result::result_type type;
+				};
+			public:
+				SPROUT_CONSTEXPR NullaryResult operator()() const {
+					return result<Derived const()>().operator()();
+				}
+				template<typename... Args>
+				SPROUT_CONSTEXPR typename result<Derived const(Args const&...)>::type
+				operator()(Args const&... args) const {
+					return result<Derived const(Args const&...)>().operator()(
+						static_cast<typename normalize_arg<Args const&>::reference>(args)...
+						);
+				}
+			};
+
+			template<typename T>
+			struct wrap_t;
+
+			typedef char poly_function_t;
+			typedef char (&mono_function_t)[2];
+			typedef char (&unknown_function_t)[3];
+
+			template<typename T> sprout::breed::detail::poly_function_t test_poly_function(
+				T const*,
+				sprout::breed::detail::wrap_t<typename T::is_poly_function_base_> const* = 0
+				);
+			template<typename T> sprout::breed::detail::mono_function_t test_poly_function(
+				T const*,
+				sprout::breed::detail::wrap_t<typename T::result_type> const* = 0
+				);
+			template<typename T> sprout::breed::detail::unknown_function_t test_poly_function(
+				T const*,
+				...
+				);
+
+			template<
+				typename Fun,
+				typename Sig,
+				typename Switch = std::integral_constant<
+					std::size_t,
+					sizeof(sprout::breed::detail::test_poly_function<Fun>(0, 0))
+				>
+			>
+			struct poly_function_traits {
+			public:
+				typedef typename Fun::template result<Sig>::type result_type;
+				typedef Fun function_type;
+			};
+			template<typename Fun, typename Sig>
+			struct poly_function_traits<
+				Fun,
+				Sig,
+				std::integral_constant<
+					std::size_t,
+					sizeof(sprout::breed::detail::mono_function_t)
+				>
+			> {
+			public:
+				typedef typename Fun::result_type result_type;
+				typedef Fun function_type;
+			};
+			template<typename PolyFun, typename... Args>
+			struct poly_function_traits<
+				PolyFun,
+				PolyFun(
+					Args...,
+					std::integral_constant<std::size_t, sizeof(sprout::breed::detail::poly_function_t)
+					)
+			> {
+			public:
+				typedef typename PolyFun::template impl<Args...> function_type;
+				typedef typename function_type::result_type result_type;
+			};
+
+			template<typename PolyFunSig, bool IsPolyFunction>
+			struct as_mono_function_impl;
+			template<typename PolyFun, typename... Args>
+			struct as_mono_function_impl<PolyFun(Args...), true> {
+			public:
+				typedef typename PolyFun::template impl<Args const...> type;
+			};
+			template<typename PolyFun, typename... Args>
+			struct as_mono_function_impl<PolyFun(Args...), false> {
+			public:
+				typedef PolyFun type;
+			};
+
+			template<typename PolyFunSig>
+			struct as_mono_function;
+			template<typename PolyFun, typename... Args>
+			struct as_mono_function<PolyFun(Args...)>
+				: public sprout::breed::detail::as_mono_function_impl<
+					PolyFun(Args...),
+					sprout::breed::detail::is_poly_function<PolyFun>::value
+				>
+			{};
+		}	// namespace detail
+	}	// namespace breed
+}	// namespace sprout
+
+#endif	// #ifndef SPROUT_BREED_DETAIL_POLY_FUNCTION_HPP
diff --git a/sprout/breed/matches.hpp b/sprout/breed/matches.hpp
index cdca04fe..d1fc8eeb 100644
--- a/sprout/breed/matches.hpp
+++ b/sprout/breed/matches.hpp
@@ -10,6 +10,8 @@
 
 namespace sprout {
 	namespace breed {
+		namespace detail {
+		}	// namespace detail
 	}	// namespace breed
 }	// namespace sprout
 
diff --git a/sprout/variant/variant.hpp b/sprout/variant/variant.hpp
index 99087fec..3d69819a 100644
--- a/sprout/variant/variant.hpp
+++ b/sprout/variant/variant.hpp
@@ -18,8 +18,8 @@ namespace sprout {
 		template<typename... Types>
 		class variant_impl {
 		protected:
-			typedef sprout::tuples::tuple<Types...> tuple_type;;
-			typedef sprout::types::type_tuple<typename std::decay<Types>::type...> uncvref_tuple_type;;
+			typedef sprout::tuples::tuple<Types...> tuple_type;
+			typedef sprout::types::type_tuple<typename std::decay<Types>::type...> uncvref_tuple_type;
 		private:
 			template<typename T, sprout::index_t... Indexes>
 			static SPROUT_CONSTEXPR tuple_type init(T&& operand, sprout::index_tuple<Indexes...>) {
@@ -62,10 +62,10 @@ namespace sprout {
 		: private sprout::detail::variant_impl<Types...>
 	{
 	private:
-		typedef sprout::detail::variant_impl<Types...> impl_type;;
-		typedef typename impl_type::uncvref_tuple_type uncvref_tuple_type;;
+		typedef sprout::detail::variant_impl<Types...> impl_type;
+		typedef typename impl_type::uncvref_tuple_type uncvref_tuple_type;
 	public:
-		typedef typename impl_type::tuple_type tuple_type;;
+		typedef typename impl_type::tuple_type tuple_type;
 	private:
 		template<int I>
 		static SPROUT_CONSTEXPR typename std::enable_if<