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+/*!
+@file
+Forward declares `boost::hana::monadic_compose`.
+
+@copyright Louis Dionne 2013-2016
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#ifndef BOOST_HANA_FWD_MONADIC_COMPOSE_HPP
+#define BOOST_HANA_FWD_MONADIC_COMPOSE_HPP
+
+#include <boost/hana/config.hpp>
+#include <boost/hana/core/when.hpp>
+
+
+BOOST_HANA_NAMESPACE_BEGIN
+    //! Composition of monadic functions.
+    //! @ingroup group-Monad
+    //!
+    //! Given two monadic functions `f` and `g`, `monadic_compose` returns
+    //! a new function equivalent to the composition of `f` with `g`, except
+    //! the result of `g` is `chain`ed into `f` instead of simply passed to
+    //! it, as with normal composition. `monadic_compose` satisfies
+    //! @code
+    //!     monadic_compose(f, g)(x) == chain(g(x), f)
+    //! @endcode
+    //!
+    //!
+    //! @note
+    //! Unlike `compose`, `monadic_compose` does not generalize nicely to
+    //! arities higher than one. Hence, only unary functions may be used
+    //! with `monadic_compose`.
+    //!
+    //!
+    //! Signature
+    //! ---------
+    //! Given a `Monad` `M` and two functions @f$ f : B \to M(C) @f$ and
+    //! @f$ g : A \to M(B) @f$, the signature is
+    //! @f$
+    //!     \mathtt{monadic\_compose}
+    //!         : (B \to M(C)) \times (A \to M(B)) \to (A \to M(C))
+    //! @f$.
+    //!
+    //! @param f
+    //! A monadic function with signature @f$ B \to M(C) @f$.
+    //!
+    //! @param g
+    //! A monadic function with signature @f$ A \to M(B) @f$.
+    //!
+    //!
+    //! @note
+    //! This method is not tag-dispatched, so it can't be customized directly.
+    //!
+    //!
+    //! Example
+    //! -------
+    //! @include example/monadic_compose.cpp
+#ifdef BOOST_HANA_DOXYGEN_INVOKED
+    constexpr auto monadic_compose = [](auto&& f, auto&& g) {
+        return [perfect-capture](auto&& x) -> decltype(auto) {
+            return hana::chain(forwarded(g)(forwarded(x)), forwarded(f));
+        };
+    };
+#else
+    struct monadic_compose_t {
+        template <typename F, typename G>
+        constexpr auto operator()(F&& f, G&& g) const;
+    };
+
+    constexpr monadic_compose_t monadic_compose{};
+#endif
+BOOST_HANA_NAMESPACE_END
+
+#endif // !BOOST_HANA_FWD_MONADIC_COMPOSE_HPP