Thrill  0.1
no_operation.hpp
Go to the documentation of this file.
1 /*******************************************************************************
2  * tlx/meta/no_operation.hpp
3  *
4  * Part of tlx - http://panthema.net/tlx
5  *
6  * Copyright (C) 2015-2019 Timo Bingmann <[email protected]>
7  *
8  * All rights reserved. Published under the Boost Software License, Version 1.0
9  ******************************************************************************/
10 
11 #ifndef TLX_META_NO_OPERATION_HEADER
12 #define TLX_META_NO_OPERATION_HEADER
13 
14 namespace tlx {
15 
16 //! \addtogroup tlx_meta
17 //! \{
18 
19 //! The noop functor, which takes any arguments and does nothing. This is a good
20 //! default argument for lambda function parameters.
21 template <typename ReturnType>
23 {
24 public:
25  explicit NoOperation(ReturnType return_value = ReturnType())
26  : return_value_(return_value) { }
27 
28  ReturnType operator () (...) const noexcept {
29  return return_value_;
30  }
31 
32 protected:
33  ReturnType return_value_;
34 };
35 
36 //! Specialized noop functor which returns a void.
37 template <>
38 class NoOperation<void>
39 {
40 public:
41  void operator () (...) const noexcept { }
42 };
43 
44 //! \}
45 
46 } // namespace tlx
47 
48 #endif // !TLX_META_NO_OPERATION_HEADER
49 
50 /******************************************************************************/
NoOperation(ReturnType return_value=ReturnType())
ReturnType operator()(...) const noexcept
ReturnType return_value_