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Diffstat (limited to 'boost/hof/mutable.hpp')
-rw-r--r-- | boost/hof/mutable.hpp | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/boost/hof/mutable.hpp b/boost/hof/mutable.hpp new file mode 100644 index 0000000000..b704c027cf --- /dev/null +++ b/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 |