11.2.0/backward/binders.h

// Functor implementations -*- C++ -*-

// Copyright (C) 2001-2021 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996-1998
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file backward/binders.h
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{functional}
 */

#ifndef _BACKWARD_BINDERS_H
#define _BACKWARD_BINDERS_H 1

// Suppress deprecated warning for this file.
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  // 20.3.6 binders
  /** @defgroup binders Binder Classes
   * @ingroup functors
   *
   *  Binders turn functions/functors with two arguments into functors
   *  with a single argument, storing an argument to be applied later.
   *  For example, a variable @c B of type @c binder1st is constructed
   *  from a functor @c f and an argument @c x. Later, B's @c
   *  operator() is called with a single argument @c y. The return
   *  value is the value of @c f(x,y). @c B can be @a called with
   *  various arguments (y1, y2, ...) and will in turn call @c
   *  f(x,y1), @c f(x,y2), ...
   *
   *  The function @c bind1st is provided to save some typing. It takes the
   *  function and an argument as parameters, and returns an instance of
   *  @c binder1st.
   *
   *  The type @c binder2nd and its creator function @c bind2nd do the same
   *  thing, but the stored argument is passed as the second parameter instead
   *  of the first, e.g., @c bind2nd(std::minus<float>(),1.3) will create a
   *  functor whose @c operator() accepts a floating-point number, subtracts
   *  1.3 from it, and returns the result. (If @c bind1st had been used,
   *  the functor would perform <em>1.3 - x</em> instead.
   *
   *  Creator-wrapper functions like @c bind1st are intended to be used in
   *  calling algorithms. Their return values will be temporary objects.
   *  (The goal is to not require you to type names like
   *  @c std::binder1st<std::plus<int>> for declaring a variable to hold the
   *  return value from @c bind1st(std::plus<int>(),5).
   *
   *  These become more useful when combined with the composition functions.
   *
   *  These functions are deprecated in C++11 and can be replaced by
   *  @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
   *  supporting functions with any number of arguments.  Uses of @c bind1st
   *  can be replaced by @c std::bind(f, x, std::placeholders::_1) and
   *  @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
   *  @{
   */
  /// One of the @link binders binder functors@endlink.
  template<typename _Operation>
    class binder1st
    : public unary_function<typename _Operation::second_argument_type,
                            typename _Operation::result_type>
    {
    protected:
      _Operation op;
      typename _Operation::first_argument_type value;

    public:
      binder1st(const _Operation& __x,
                const typename _Operation::first_argument_type& __y)
      : op(__x), value(__y) { }

      typename _Operation::result_type
      operator()(const typename _Operation::second_argument_type& __x) const
      { return op(value, __x); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 109.  Missing binders for non-const sequence elements
      typename _Operation::result_type
      operator()(typename _Operation::second_argument_type& __x) const
      { return op(value, __x); }
    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation, typename _Tp>
    inline binder1st<_Operation>
    bind1st(const _Operation& __fn, const _Tp& __x)
    {
      typedef typename _Operation::first_argument_type _Arg1_type;
      return binder1st<_Operation>(__fn, _Arg1_type(__x));
    }

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation>
    class binder2nd
    : public unary_function<typename _Operation::first_argument_type,
                            typename _Operation::result_type>
    {
    protected:
      _Operation op;
      typename _Operation::second_argument_type value;

    public:
      binder2nd(const _Operation& __x,
                const typename _Operation::second_argument_type& __y)
      : op(__x), value(__y) { }

      typename _Operation::result_type
      operator()(const typename _Operation::first_argument_type& __x) const
      { return op(__x, value); }

      // _GLIBCXX_RESOLVE_LIB_DEFECTS
      // 109.  Missing binders for non-const sequence elements
      typename _Operation::result_type
      operator()(typename _Operation::first_argument_type& __x) const
      { return op(__x, value); }
    } _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");

  /// One of the @link binders binder functors@endlink.
  template<typename _Operation, typename _Tp>
    inline binder2nd<_Operation>
    bind2nd(const _Operation& __fn, const _Tp& __x)
    {
      typedef typename _Operation::second_argument_type _Arg2_type;
      return binder2nd<_Operation>(__fn, _Arg2_type(__x));
    } 
  /** @}  */

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace

#pragma GCC diagnostic pop

#endif /* _BACKWARD_BINDERS_H */
Revision:	1166
Committed:	Tue Oct 26 14:22:36 2021 UTC (4 years ago) by rossy
Content type:	text/x-chdr
File size:	7213 byte(s)
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#	Content
1	// Functor implementations -- C++ --
2
3	// Copyright (C) 2001-2021 Free Software Foundation, Inc.
4	//
5	// This file is part of the GNU ISO C++ Library. This library is free
6	// software; you can redistribute it and/or modify it under the
7	// terms of the GNU General Public License as published by the
8	// Free Software Foundation; either version 3, or (at your option)
9	// any later version.
10
11	// This library is distributed in the hope that it will be useful,
12	// but WITHOUT ANY WARRANTY; without even the implied warranty of
13	// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14	// GNU General Public License for more details.
15
16	// Under Section 7 of GPL version 3, you are granted additional
17	// permissions described in the GCC Runtime Library Exception, version
18	// 3.1, as published by the Free Software Foundation.
19
20	// You should have received a copy of the GNU General Public License and
21	// a copy of the GCC Runtime Library Exception along with this program;
22	// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23	// <http://www.gnu.org/licenses/>.
24
25	/*
26	*
27	* Copyright (c) 1994
28	* Hewlett-Packard Company
29	*
30	* Permission to use, copy, modify, distribute and sell this software
31	* and its documentation for any purpose is hereby granted without fee,
32	* provided that the above copyright notice appear in all copies and
33	* that both that copyright notice and this permission notice appear
34	* in supporting documentation. Hewlett-Packard Company makes no
35	* representations about the suitability of this software for any
36	* purpose. It is provided "as is" without express or implied warranty.
37	*
38	*
39	* Copyright (c) 1996-1998
40	* Silicon Graphics Computer Systems, Inc.
41	*
42	* Permission to use, copy, modify, distribute and sell this software
43	* and its documentation for any purpose is hereby granted without fee,
44	* provided that the above copyright notice appear in all copies and
45	* that both that copyright notice and this permission notice appear
46	* in supporting documentation. Silicon Graphics makes no
47	* representations about the suitability of this software for any
48	* purpose. It is provided "as is" without express or implied warranty.
49	*/
50
51	/** @file backward/binders.h
52	* This is an internal header file, included by other library headers.
53	* Do not attempt to use it directly. @headername{functional}
54	*/
55
56	#ifndef _BACKWARD_BINDERS_H
57	#define _BACKWARD_BINDERS_H 1
58
59	// Suppress deprecated warning for this file.
60	#pragma GCC diagnostic push
61	#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
62
63	namespace std _GLIBCXX_VISIBILITY(default)
64	{
65	_GLIBCXX_BEGIN_NAMESPACE_VERSION
66
67	// 20.3.6 binders
68	/** @defgroup binders Binder Classes
69	* @ingroup functors
70	*
71	* Binders turn functions/functors with two arguments into functors
72	* with a single argument, storing an argument to be applied later.
73	* For example, a variable @c B of type @c binder1st is constructed
74	* from a functor @c f and an argument @c x. Later, B's @c
75	* operator() is called with a single argument @c y. The return
76	* value is the value of @c f(x,y). @c B can be @a called with
77	* various arguments (y1, y2, ...) and will in turn call @c
78	* f(x,y1), @c f(x,y2), ...
79	*
80	* The function @c bind1st is provided to save some typing. It takes the
81	* function and an argument as parameters, and returns an instance of
82	* @c binder1st.
83	*
84	* The type @c binder2nd and its creator function @c bind2nd do the same
85	* thing, but the stored argument is passed as the second parameter instead
86	* of the first, e.g., @c bind2nd(std::minus<float>(),1.3) will create a
87	* functor whose @c operator() accepts a floating-point number, subtracts
88	* 1.3 from it, and returns the result. (If @c bind1st had been used,
89	* the functor would perform <em>1.3 - x</em> instead.
90	*
91	* Creator-wrapper functions like @c bind1st are intended to be used in
92	* calling algorithms. Their return values will be temporary objects.
93	* (The goal is to not require you to type names like
94	* @c std::binder1st<std::plus<int>> for declaring a variable to hold the
95	* return value from @c bind1st(std::plus<int>(),5).
96	*
97	* These become more useful when combined with the composition functions.
98	*
99	* These functions are deprecated in C++11 and can be replaced by
100	* @c std::bind (or @c std::tr1::bind) which is more powerful and flexible,
101	* supporting functions with any number of arguments. Uses of @c bind1st
102	* can be replaced by @c std::bind(f, x, std::placeholders::_1) and
103	* @c bind2nd by @c std::bind(f, std::placeholders::_1, x).
104	* @{
105	*/
106	/// One of the @link binders binder functors@endlink.
107	template<typename _Operation>
108	class binder1st
109	: public unary_function<typename _Operation::second_argument_type,
110	typename _Operation::result_type>
111	{
112	protected:
113	_Operation op;
114	typename _Operation::first_argument_type value;
115
116	public:
117	binder1st(const _Operation& __x,
118	const typename _Operation::first_argument_type& __y)
119	: op(__x), value(__y) { }
120
121	typename _Operation::result_type
122	operator()(const typename _Operation::second_argument_type& __x) const
123	{ return op(value, __x); }
124
125	// _GLIBCXX_RESOLVE_LIB_DEFECTS
126	// 109. Missing binders for non-const sequence elements
127	typename _Operation::result_type
128	operator()(typename _Operation::second_argument_type& __x) const
129	{ return op(value, __x); }
130	} _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
131
132	/// One of the @link binders binder functors@endlink.
133	template<typename _Operation, typename _Tp>
134	inline binder1st<_Operation>
135	bind1st(const _Operation& __fn, const _Tp& __x)
136	{
137	typedef typename _Operation::first_argument_type _Arg1_type;
138	return binder1st<_Operation>(__fn, _Arg1_type(__x));
139	}
140
141	/// One of the @link binders binder functors@endlink.
142	template<typename _Operation>
143	class binder2nd
144	: public unary_function<typename _Operation::first_argument_type,
145	typename _Operation::result_type>
146	{
147	protected:
148	_Operation op;
149	typename _Operation::second_argument_type value;
150
151	public:
152	binder2nd(const _Operation& __x,
153	const typename _Operation::second_argument_type& __y)
154	: op(__x), value(__y) { }
155
156	typename _Operation::result_type
157	operator()(const typename _Operation::first_argument_type& __x) const
158	{ return op(__x, value); }
159
160	// _GLIBCXX_RESOLVE_LIB_DEFECTS
161	// 109. Missing binders for non-const sequence elements
162	typename _Operation::result_type
163	operator()(typename _Operation::first_argument_type& __x) const
164	{ return op(__x, value); }
165	} _GLIBCXX11_DEPRECATED_SUGGEST("std::bind");
166
167	/// One of the @link binders binder functors@endlink.
168	template<typename _Operation, typename _Tp>
169	inline binder2nd<_Operation>
170	bind2nd(const _Operation& __fn, const _Tp& __x)
171	{
172	typedef typename _Operation::second_argument_type _Arg2_type;
173	return binder2nd<_Operation>(__fn, _Arg2_type(__x));
174	}
175	/** @} */
176
177	_GLIBCXX_END_NAMESPACE_VERSION
178	} // namespace
179
180	#pragma GCC diagnostic pop
181
182	#endif /* _BACKWARD_BINDERS_H */