feat():initial version

install/boost_1_75_0/include/boost/hof/flip.hpp

@@ -0,0 +1,107 @@
+/*=============================================================================
+    Copyright (c) 2015 Paul Fultz II
+    flip.h
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
+    file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+==============================================================================*/
+
+#ifndef BOOST_HOF_GUARD_FLIP_H
+#define BOOST_HOF_GUARD_FLIP_H
+
+/// flip
+/// ====
+/// 
+/// Description
+/// -----------
+/// 
+/// The `flip` function adaptor swaps the first two parameters.
+/// 
+/// Synopsis
+/// --------
+/// 
+///     template<class F>
+///     flip_adaptor<F> flip(F f);
+/// 
+/// Semantics
+/// ---------
+/// 
+///     assert(flip(f)(x, y, xs...) == f(y, x, xs...));
+/// 
+/// Requirements
+/// ------------
+/// 
+/// F must be at least:
+/// 
+/// * [BinaryInvocable](BinaryInvocable)
+/// 
+/// Or:
+/// 
+/// * [Invocable](Invocable) with more than two argurments
+/// 
+/// And:
+/// 
+/// * MoveConstructible
+/// 
+/// Example
+/// -------
+/// 
+///     #include <boost/hof.hpp>
+///     #include <cassert>
+/// 
+///     int main() {
+///         int r = boost::hof::flip(boost::hof::_ - boost::hof::_)(2, 5);
+///         assert(r == 3);
+///     }
+/// 
+
+#include <boost/hof/detail/callable_base.hpp>
+#include <boost/hof/reveal.hpp>
+#include <boost/hof/detail/make.hpp>
+#include <boost/hof/detail/static_const_var.hpp>
+
+namespace boost { namespace hof {
+
+template<class F>
+struct flip_adaptor : detail::callable_base<F>
+{
+    typedef flip_adaptor fit_rewritable1_tag;
+    BOOST_HOF_INHERIT_CONSTRUCTOR(flip_adaptor, detail::callable_base<F>);
+
+    template<class... Ts>
+    constexpr const detail::callable_base<F>& base_function(Ts&&... xs) const
+    {
+        return boost::hof::always_ref(*this)(xs...);
+    }
+
+    struct flip_failure
+    {
+        template<class Failure>
+        struct apply
+        {
+            template<class T, class U, class... Ts>
+            struct of
+            : Failure::template of<U, T, Ts...>
+            {};
+        };
+    };
+
+    struct failure
+    : failure_map<flip_failure, detail::callable_base<F>>
+    {};
+
+    BOOST_HOF_RETURNS_CLASS(flip_adaptor);
+
+    template<class T, class U, class... Ts>
+    constexpr BOOST_HOF_SFINAE_RESULT(const detail::callable_base<F>&, id_<U>, id_<T>, id_<Ts>...) 
+    operator()(T&& x, U&& y, Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
+    (
+        (BOOST_HOF_MANGLE_CAST(const detail::callable_base<F>&)(BOOST_HOF_CONST_THIS->base_function(xs...)))
+            (BOOST_HOF_FORWARD(U)(y), BOOST_HOF_FORWARD(T)(x), BOOST_HOF_FORWARD(Ts)(xs)...)
+    );
+};
+
+BOOST_HOF_DECLARE_STATIC_VAR(flip, detail::make<flip_adaptor>);
+
+}} // namespace boost::hof
+
+#endif