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Sprout/sprout/functional/bind2nd.hpp
2016-02-25 18:48:28 +09:00

92 lines
2.8 KiB
C++

/*=============================================================================
Copyright (c) 2011 RiSK (sscrisk)
https://github.com/sscrisk/CEL---ConstExpr-Library
Copyright (c) 2011-2016 Bolero MURAKAMI
https://github.com/bolero-MURAKAMI/Sprout
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 SPROUT_FUNCTIONAL_BIND2ND_HPP
#define SPROUT_FUNCTIONAL_BIND2ND_HPP
#include <type_traits>
#include <utility>
#include <sprout/config.hpp>
#include <sprout/functional/base.hpp>
#include <sprout/functional/type_traits/is_strict_function.hpp>
namespace sprout {
// D.9.3 Class template binder2nd
namespace detail {
template<typename Fn, typename T = void, typename = void>
class binder2nd;
template<typename Fn, typename T>
class binder2nd<
Fn, T,
typename std::enable_if<sprout::is_strict_binary_function<Fn>::value>::type
>
: public sprout::unary_function<typename Fn::first_argument_type, typename Fn::result_type>
{
public:
typedef typename std::conditional<
std::is_void<T>::value,
typename Fn::second_argument_type,
T
>::type value_type;
protected:
Fn op;
value_type value;
public:
SPROUT_CONSTEXPR binder2nd(Fn const& x, value_type const& y)
: op(x), value(y)
{}
SPROUT_CONSTEXPR typename Fn::result_type
operator()(typename Fn::first_argument_type const& x) const {
return op(x, value);
}
};
template<typename Fn, typename T>
class binder2nd<
Fn, T,
typename std::enable_if<!sprout::is_strict_binary_function<Fn>::value>::type
> {
public:
typedef T value_type;
protected:
Fn op;
value_type value;
public:
SPROUT_CONSTEXPR binder2nd(Fn const& x, value_type const& y)
: op(x), value(y)
{}
template<typename U>
SPROUT_CONSTEXPR decltype(std::declval<Fn const&>()(std::declval<U const&>(), std::declval<value_type const&>()))
operator()(U const& x) const {
return op(x, value);
}
};
} // namespace detail
template<typename Fn, typename T = void>
class binder2nd
: public sprout::detail::binder2nd<Fn, T>
{
public:
typedef typename sprout::detail::binder2nd<Fn, T>::value_type value_type;
public:
SPROUT_CONSTEXPR binder2nd(Fn const& x, value_type const& y)
: sprout::detail::binder2nd<Fn, T>(x, y)
{}
};
// D.9.3 bind2nd
template<typename Fn, typename T>
inline SPROUT_CONSTEXPR sprout::binder2nd<Fn, T>
bind2nd(Fn const& fn, T const& x) {
return sprout::binder2nd<Fn, T>(fn, typename sprout::binder2nd<Fn, T>::value_type(x));
}
} // namespace sprout
#endif // #ifndef SPROUT_FUNCTIONAL_BIND2ND_HPP