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Sprout/sprout/utility/fold.hpp
2018-12-30 17:25:21 +09:00

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3.4 KiB
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/*=============================================================================
Copyright (c) 2011-2018 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_UTILITY_FOLD_HPP
#define SPROUT_UTILITY_FOLD_HPP
#include <sprout/config.hpp>
#include <sprout/utility/forward.hpp>
#include <sprout/utility/move.hpp>
namespace sprout {
template<typename BinaryOperation>
class folder_forwarder {
public:
typedef BinaryOperation function_type;
private:
function_type binary_op_;
public:
explicit SPROUT_CONSTEXPR folder_forwarder(function_type const& binary_op)
: binary_op_(binary_op)
{}
SPROUT_CONSTEXPR function_type const& func() const {
return binary_op_;
}
};
template<typename BinaryOperation, typename T>
class folder {
public:
typedef BinaryOperation function_type;
typedef T value_type;
private:
function_type binary_op_;
value_type value_;
public:
explicit SPROUT_CONSTEXPR folder(function_type const& binary_op, value_type const& value)
: binary_op_(binary_op), value_(value)
{}
template<typename U>
SPROUT_CXX14_CONSTEXPR folder& left(U&& val) {
return (value_ = binary_op_(value_, SPROUT_FORWARD(U, val))), *this;
}
template<typename U>
SPROUT_CXX14_CONSTEXPR folder& right(U&& val) {
return (value_ = binary_op_(SPROUT_FORWARD(U, val), value_)), *this;
}
SPROUT_CONSTEXPR function_type const& func() const {
return binary_op_;
}
SPROUT_CONSTEXPR value_type value() const {
return value_;
}
SPROUT_CONSTEXPR value_type get() const {
return value_;
}
SPROUT_CONSTEXPR operator value_type() const {
return value_;
}
};
template<typename BinaryOperation, typename T>
inline SPROUT_CONSTEXPR sprout::folder<BinaryOperation, T>
operator,(sprout::folder_forwarder<BinaryOperation> const& lhs, T&& rhs) {
return sprout::folder<BinaryOperation, T>(lhs.func(), SPROUT_FORWARD(T, rhs));
}
template<typename BinaryOperation, typename T>
inline SPROUT_CONSTEXPR sprout::folder<BinaryOperation, T>
operator,(T&& lhs, sprout::folder_forwarder<BinaryOperation> const& rhs) {
return sprout::folder<BinaryOperation, T>(rhs.func(), SPROUT_FORWARD(T, lhs));
}
template<typename BinaryOperation, typename T, typename U>
inline SPROUT_CONSTEXPR sprout::folder<BinaryOperation, T>&&
operator,(sprout::folder<BinaryOperation, T>&& lhs, U&& rhs) {
return sprout::move(lhs.left(SPROUT_FORWARD(U, rhs)));
}
template<typename BinaryOperation, typename T, typename U>
inline SPROUT_CONSTEXPR sprout::folder<BinaryOperation, T>&&
operator,(U&& lhs, sprout::folder<BinaryOperation, T>&& rhs) {
return sprout::move(rhs.right(SPROUT_FORWARD(U, lhs)));
}
template<typename BinaryOperation>
inline SPROUT_CONSTEXPR sprout::folder_forwarder<BinaryOperation>
fold_by(BinaryOperation const& binary_op) {
return sprout::folder_forwarder<BinaryOperation>(binary_op);
}
template<typename BinaryOperation, typename T>
inline SPROUT_CONSTEXPR sprout::folder<BinaryOperation, T>
fold_by(BinaryOperation const& binary_op, T&& init) {
return sprout::folder<BinaryOperation, T>(binary_op, SPROUT_FORWARD(T, init));
}
} // namespace sprout
#endif // #ifndef SPROUT_UTILITY_FOLD_HPP