54 lines
1.5 KiB
C++
54 lines
1.5 KiB
C++
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/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Copyright 2018 Danny Robson <danny@nerdcruft.net>
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*/
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#pragma once
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#include <utility>
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namespace util::functor {
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///////////////////////////////////////////////////////////////////////////
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/// returns the value provided at construction time regardless of the
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/// arguments supplied in the call operator.
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template <typename ValueT>
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class constant {
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public:
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constant (const ValueT &_value):
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m_value (_value)
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{ ; }
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template <typename ...Args>
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ValueT&
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operator() (Args&&...) noexcept
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{ return m_value; }
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template <typename ...Args>
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const ValueT&
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operator() (Args&&...) const noexcept
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{ return m_value; }
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private:
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ValueT m_value;
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};
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//-------------------------------------------------------------------------
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template <typename ValueT>
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constant (ValueT) -> constant<std::decay_t<ValueT>>;
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};
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