libcruft-util/functor.hpp
Danny Robson f6056153e3 rename root namespace from util to cruft
This places, at long last, the core library code into the same namespace
as the extended library code.
2018-08-05 14:42:02 +10:00

46 lines
1.1 KiB
C++

/*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*
* Copyright 2018 Danny Robson <danny@nerdcruft.net>
*/
#pragma once
#include <utility>
namespace cruft::functor {
///////////////////////////////////////////////////////////////////////////
/// returns the value provided at construction time regardless of the
/// arguments supplied in the call operator.
template <typename ValueT>
class constant {
public:
constant (const ValueT &_value):
m_value (_value)
{ ; }
template <typename ...Args>
ValueT&
operator() (Args&&...) noexcept
{ return m_value; }
template <typename ...Args>
const ValueT&
operator() (Args&&...) const noexcept
{ return m_value; }
private:
ValueT m_value;
};
//-------------------------------------------------------------------------
template <typename ValueT>
constant (ValueT) -> constant<std::decay_t<ValueT>>;
};