feat():initial version

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

@@ -0,0 +1,68 @@
+/*=============================================================================
+    Copyright (c) 2014 Paul Fultz II
+    mutable.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_FUNCTION_MUTABLE_H
+#define BOOST_HOF_GUARD_FUNCTION_MUTABLE_H
+
+/// mutable
+/// =======
+/// 
+/// Description
+/// -----------
+/// 
+/// The `mutable` function adaptor allows using a non-const function object
+/// inside of a const-function object. In Fit, all the function adaptors use
+/// `const` call overloads, so if there is a function that has a non-const
+/// call operator, it couldn't be used directly. So, `mutable_` allows the
+/// function to be used inside of the call operator.
+/// 
+/// NOTE: This function should be used with caution since many functions are
+/// copied, so relying on some internal shared state can be error-prone.
+/// 
+/// Synopsis
+/// --------
+/// 
+///     template<class F>
+///     mutable_adaptor<F> mutable_(F f)
+/// 
+/// Requirements
+/// ------------
+/// 
+/// F must be:
+/// 
+/// * [MutableFunctionObject](MutableFunctionObject)
+/// * MoveConstructible
+/// 
+
+#include <boost/hof/detail/result_of.hpp>
+#include <boost/hof/detail/delegate.hpp>
+#include <boost/hof/detail/move.hpp>
+#include <boost/hof/detail/make.hpp>
+#include <boost/hof/detail/static_const_var.hpp>
+
+namespace boost { namespace hof {
+
+template<class F>
+struct mutable_adaptor
+{
+    mutable F f;
+
+    BOOST_HOF_DELEGATE_CONSTRUCTOR(mutable_adaptor, F, f);
+
+    BOOST_HOF_RETURNS_CLASS(mutable_adaptor);
+
+    template<class... Ts>
+    BOOST_HOF_SFINAE_RESULT(F, id_<Ts>...) 
+    operator()(Ts&&... xs) const BOOST_HOF_SFINAE_RETURNS(BOOST_HOF_CONST_THIS->f(BOOST_HOF_FORWARD(Ts)(xs)...));
+};
+
+BOOST_HOF_DECLARE_STATIC_VAR(mutable_, detail::make<mutable_adaptor>);
+
+}} // namespace boost::hof
+
+
+#endif