1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
|
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<!-- Copyright David Abrahams 2006. 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) -->
<html>
<head>
<meta name="generator" content=
"HTML Tidy for Cygwin (vers 1st April 2002), see www.w3.org">
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<link rel="stylesheet" type="text/css" href="../boost.css">
<title>Boost.Python - <boost/python/data_members.hpp></title>
</head>
<body>
<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
"header">
<tr>
<td valign="top" width="300">
<h3><a href="../../../../index.htm"><img height="86" width="277"
alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3>
</td>
<td valign="top">
<h1 align="center"><a href="../index.html">Boost.Python</a></h1>
<h2 align="center">Header
<boost/python/data_members.hpp></h2>
</td>
</tr>
</table>
<hr>
<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href="#functions">Functions</a></dt>
<dd>
<dl class="page-index">
<dt><a href="#make_getter-spec">make_getter</a></dt>
<dt><a href="#make_setter-spec">make_setter</a></dt>
</dl>
</dd>
<dt><a href="#examples">Example</a></dt>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p><code><a href="#make_getter-spec">make_getter</a>()</code> and
<code><a href="#make_setter-spec">make_setter</a>()</code> are the
functions used internally by <code>class_<>::<a href=
"class.html#class_-spec-modifiers">def_readonly</a></code> and
<code>class_<>::<a href=
"class.html#class_-spec-modifiers">def_readwrite</a></code> to produce
Python callable objects which wrap C++ data members.</p>
<h2><a name="functions"></a>Functions</h2>
<pre>
<a name="make_getter-spec">template <class C, class D></a>
<a href="object.html#object-spec">object</a> make_getter(D C::*pm);
template <class C, class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_getter(D C::*pm, Policies const& policies);
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>Policies</code> is a model of <a href=
"CallPolicies.html">CallPolicies</a>.</dt>
<dt><b>Effects:</b> Creates a Python callable object which accepts a
single argument that can be converted <code>from_python</code> to
<code>C*</code>, and returns the corresponding member <code>D</code>
member of the <code>C</code> object, converted <code>to_python</code>.
If <code>policies</code> is supplied, it will be applied to the
function as described <a href="CallPolicies.html">here</a>. Otherwise,
the library attempts to determine whether <code>D</code> is a
user-defined class type, and if so uses <code><a href=
"return_internal_reference.html#return_internal_reference-spec">return_internal_reference</a><></code></dt>
<dt>for <code>Policies</code>. Note that this test may inappropriately
choose <code>return_internal_reference<></code> in some cases
when <code>D</code> is a smart pointer type. This is a known
defect.</dt>
<dt><b>Returns:</b> An instance of <a href=
"object.html#object-spec">object</a> which holds the new Python
callable object.</dt>
</dl>
<pre>
template <class D>
<a href="object.html#object-spec">object</a> make_getter(D const& d);
template <class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_getter(D const& d, Policies const& policies);
template <class D>
<a href="object.html#object-spec">object</a> make_getter(D const* p);
template <class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_getter(D const* p, Policies const& policies);
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>Policies</code> is a model of <a href=
"CallPolicies.html">CallPolicies</a>.</dt>
<dt><b>Effects:</b> Creates a Python callable object which accepts no
arguments and returns <code>d</code> or <code>*p</code>, converted
<code>to_python</code> on demand. If <code>policies</code> is supplied,
it will be applied to the function as described <a href=
"CallPolicies.html">here</a>. Otherwise, the library attempts to
determine whether <code>D</code> is a user-defined class type, and if
so uses <code><a href=
"reference_existing_object.html#reference_existing_object-spec">reference_existing_object</a></code></dt>
<dt>for <code>Policies</code>.</dt>
<dt><b>Returns:</b> An instance of <a href=
"object.html#object-spec">object</a> which holds the new Python
callable object.</dt>
</dl>
<pre>
<a name="make_setter-spec">template <class C, class D></a>
<a href="object.html#object-spec">object</a> make_setter(D C::*pm);
template <class C, class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_setter(D C::*pm, Policies const& policies);
</pre>
<dl class="function*-semantics">
<dt><b>Requires:</b> <code>Policies</code> is a model of <a href=
"CallPolicies.html">CallPolicies</a>.</dt>
<dt><b>Effects:</b> Creates a Python callable object which, when called
from Python, expects two arguments which can be converted
<code>from_python</code> to <code>C*</code> and
<code>D const&</code>, respectively, and sets the
corresponding <code>D</code> member of the <code>C</code> object. If
<code>policies</code> is supplied, it will be applied to the function
as described <a href="CallPolicies.html">here</a>.</dt>
<dt><b>Returns:</b> An instance of <a href=
"object.html#object-spec">object</a> which holds the new Python
callable object.</dt>
</dl>
<pre>
template <class D>
<a href="object.html#object-spec">object</a> make_setter(D& d);
template <class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_setter(D& d, Policies const& policies);
template <class D>
<a href="object.html#object-spec">object</a> make_setter(D* p);
template <class D, class Policies>
<a href=
"object.html#object-spec">object</a> make_setter(D* p, Policies const& policies);
</pre>
<dl class="function-semantics">
<dt><b>Requires:</b> <code>Policies</code> is a model of <a href=
"CallPolicies.html">CallPolicies</a>.</dt>
<dt><b>Effects:</b> Creates a Python callable object which accepts one
argument, which is converted from Python to <code>D const&</code>
and written into <code>d</code> or <code>*p</code>, respectively. If
<code>policies</code> is supplied, it will be applied to the function
as described <a href="CallPolicies.html">here</a>.</dt>
<dt><b>Returns:</b> An instance of <a href=
"object.html#object-spec">object</a> which holds the new Python
callable object.</dt>
</dl>
<h2><a name="examples"></a>Example</h2>
<p>The code below uses make_getter and make_setter to expose a data
member as functions:</p>
<pre>
#include <boost/python/data_members.hpp>
#include <boost/python/module.hpp>
#include <boost/python/class.hpp>
struct X
{
X(int x) : y(x) {}
int y;
};
using namespace boost::python;
BOOST_PYTHON_MODULE_INIT(data_members_example)
{
class_<X>("X", init<int>())
.def("get", make_getter(&X::y))
.def("set", make_setter(&X::y))
;
}
</pre>
It can be used this way in Python:
<pre>
>>> from data_members_example import *
>>> x = X(1)
>>> x.get()
1
>>> x.set(2)
>>> x.get()
2
</pre>
<p>
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
5 August, 2003 <!--webbot bot="Timestamp" endspan i-checksum="39359" -->
</p>
<p><i>© Copyright <a href=
"http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p>
</body>
</html>
|
