add boost on mac

macx64/include/boost/hof/repeat_while.hpp

@@ -0,0 +1,181 @@
+/*=============================================================================
+    Copyright (c) 2015 Paul Fultz II
+    repeat_while.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_REPEAT_WHILE_H
+#define BOOST_HOF_GUARD_REPEAT_WHILE_H
+
+/// repeat_while
+/// ======
+/// 
+/// Description
+/// -----------
+/// 
+/// The `repeat_while` function decorator will repeatedly apply a function while
+/// the predicate returns a boolean that is true. If the predicate returns an
+/// `IntergralConstant` then the predicate is only evaluated at compile-time.
+/// 
+/// 
+/// Synopsis
+/// --------
+/// 
+///     template<class Predicate>
+///     constexpr auto repeat_while(Predicate predicate);
+/// 
+/// Requirements
+/// ------------
+/// 
+/// Predicate must be:
+/// 
+/// * [ConstFunctionObject](ConstFunctionObject)
+/// * MoveConstructible
+/// 
+/// Example
+/// -------
+/// 
+///     #include <boost/hof.hpp>
+///     #include <cassert>
+/// 
+///     struct increment
+///     {
+///         template<class T>
+///         constexpr std::integral_constant<int, T::value + 1> operator()(T) const
+///         {
+///             return std::integral_constant<int, T::value + 1>();
+///         }
+///     };
+/// 
+///     struct not_6
+///     {
+///         template<class T>
+///         constexpr std::integral_constant<bool, (T::value != 6)> 
+///         operator()(T) const
+///         {
+///             return std::integral_constant<bool, (T::value != 6)>();
+///         }
+///     };
+/// 
+///     typedef std::integral_constant<int, 1> one;
+///     typedef std::integral_constant<int, 6> six;
+/// 
+///     int main() {
+///         auto increment_until_6 = boost::hof::repeat_while(not_6())(increment());
+///         static_assert(std::is_same<six, decltype(increment_until_6(one()))>::value, "Error");
+///     }
+/// 
+
+#include <boost/hof/always.hpp>
+#include <boost/hof/detail/delegate.hpp>
+#include <boost/hof/detail/result_of.hpp>
+#include <boost/hof/detail/move.hpp>
+#include <boost/hof/decorate.hpp>
+#include <boost/hof/detail/static_const_var.hpp>
+#include <boost/hof/first_of.hpp>
+#include <boost/hof/detail/recursive_constexpr_depth.hpp>
+
+namespace boost { namespace hof { namespace detail {
+
+template<class P, class... Ts>
+struct compute_predicate
+{
+    typedef decltype(std::declval<P>()(std::declval<Ts>()...)) type;
+};
+
+template<bool B>
+struct while_repeater
+{
+    template<class F, class P, class... Ts>
+    constexpr BOOST_HOF_SFINAE_RESULT(while_repeater<
+        compute_predicate<P, typename result_of<const F&, id_<Ts>...>::type>::type::value
+    >, id_<const F&>, id_<const P&>, result_of<const F&, id_<Ts>...>) 
+    operator()(const F& f, const P& p, Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS
+    (
+        while_repeater<
+            compute_predicate<P, decltype(f(BOOST_HOF_FORWARD(Ts)(xs)...))>::type::value
+        >()(f, p, f(BOOST_HOF_FORWARD(Ts)(xs)...))
+    );
+};
+
+template<>
+struct while_repeater<false>
+{
+    template<class F, class P, class T>
+    constexpr T operator()(const F&, const P&, T&& x) const 
+    BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT(x)
+    {
+        return x;
+    }
+};
+
+struct repeat_while_constant_decorator
+{
+    template<class P, class F, class... Ts>
+    constexpr auto operator()(const P& p, const F& f, Ts&&... xs) const BOOST_HOF_RETURNS
+    (
+        detail::while_repeater<
+            detail::compute_predicate<P, decltype(std::declval<F>()(BOOST_HOF_FORWARD(Ts)(xs)...))>::type::value
+        >()
+        (
+            f, 
+            p, 
+            BOOST_HOF_FORWARD(Ts)(xs)...
+        )
+    );
+};
+
+template<int Depth>
+struct repeat_while_integral_decorator
+{
+    template<class P, class F, class T, class... Ts, class Self=repeat_while_integral_decorator<Depth-1>>
+    constexpr auto operator()(const P& p, const F& f, T&& x, Ts&&... xs) const BOOST_HOF_RETURNS
+    (
+        (p(x, BOOST_HOF_FORWARD(Ts)(xs)...)) ? 
+            Self()(
+                p, 
+                f, 
+                f(x, BOOST_HOF_FORWARD(Ts)(xs)...)
+            ) : 
+            BOOST_HOF_FORWARD(T)(x)
+    );
+};
+
+template<>
+struct repeat_while_integral_decorator<0>
+{
+    template<class P, class F, class T, class Self=repeat_while_integral_decorator<0>>
+#if BOOST_HOF_HAS_RELAXED_CONSTEXPR
+    constexpr
+#endif
+    auto operator()(const P& p, const F& f, T x) const 
+    BOOST_HOF_RETURNS_DEDUCE_NOEXCEPT((p(x), f(x)))
+    -> decltype(f(x))
+    {
+        while(p(x))
+        {
+            // TODO: Should move?
+            x = f(x);
+        }
+        return x;
+    }
+};
+}
+
+#if BOOST_HOF_HAS_RELAXED_CONSTEXPR
+#define BOOST_HOF_REPEAT_WHILE_CONSTEXPR_DEPTH 1
+#else
+#define BOOST_HOF_REPEAT_WHILE_CONSTEXPR_DEPTH BOOST_HOF_RECURSIVE_CONSTEXPR_DEPTH
+#endif
+
+BOOST_HOF_DECLARE_STATIC_VAR(repeat_while, decorate_adaptor<
+    boost::hof::first_of_adaptor<
+        detail::repeat_while_constant_decorator,
+        detail::repeat_while_integral_decorator<BOOST_HOF_REPEAT_WHILE_CONSTEXPR_DEPTH>
+    >
+>);
+
+}} // namespace boost::hof
+
+#endif