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 Windows (vers 1st August 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/overloads.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/overloads.hpp></h2>
</td>
</tr>
</table>
<hr>
<h2>Contents</h2>
<dl class="page-index">
<dt><a href="#introduction">Introduction</a></dt>
<dt><a href=
"#overload-dispatch-expression"><i>overload-dispatch-expressions</i></a></dt>
<dt><a href= "#OverloadDispatcher-concept">OverloadDispatcher</a> concept</dt>
<dt><a href="#macros">Macros</a></dt>
<dd>
<dl class="page-index">
<dt><a href=
"#BOOST_PYTHON_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_FUNCTION_OVERLOADS</a></dt>
<dt><a href=
"#BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS</a></dt>
</dl>
</dd>
<dt><a href="#examples">Example(s)</a></dt>
</dl>
<hr>
<h2><a name="introduction"></a>Introduction</h2>
<p>Defines facilities for generating families of overloaded Python
functions and extension class methods from C++ functions and
member functions with default arguments, or from similar families
of C++ overloads</p>
<h2><a name=
"overload-dispatch-expression"></a><i>overload-dispatch-expressions</i></h2>
<p>
An <em>overload-dispatch-expression</em> is used to describe a
family of overloaded methods to be generated for an extension
class. It has the following properties:
<blockquote>
<dl class="properties">
<dt><b>docstring:</b> An <a href="definitions.html#ntbs">ntbs</a>
whose value will bound to the methods' <code>__doc__</code>
attribute</dt>
<dt><b>keywords:</b> A <a href=
"args.html#keyword-expression">keyword-expression</a> which
will be used to name (a trailing subsequence of) the arguments
to the generated methods.</dt>
<dt><b>call policies:</b> An instance of some type which models <a href=
"CallPolicies.html">CallPolicies</a>.</dt>
<dt><b>minimum <a href="definitions.html#arity">arity</a></b>
The minimum number of arguments to be accepted by a generated
method overload.</dt>
<dt><b>maximum <a href="definitions.html#arity">arity</a></b>
The maximum number of arguments to be accepted by a generated
method overload.</dt>
</dl>
</blockquote>
<h2><a name="OverloadDispatcher-concept"></a>OverloadDispatcher Concept</h2>
An OverloadDispatcher <code>X</code> is a class which has a
<em>minimum arity</em> and a <em>maximum arity</em>, and for which
the following following are valid <a
href="#overload-dispatch-expression"><em>overload-dispatch-expression</em></a>s,
with the same minimum and maximum arity as the OverloadDispatcher.
<pre>
X()
X(docstring)
X(docstring, keywords)
X(keywords, docstring)
X()[policies]
X(docstring)[policies]
X(docstring, keywords)[policies]
X(keywords, docstring)[policies]
</pre>
<ul>
<li>If <code>policies</code> are supplied, it must be an instance of a
type which models <a
href="CallPolicies.html#CallPolicies-concept">CallPolicies</a>, and
will be used as the result's call policies. Otherwise the result's
call policies will be an instance of <a
href="default_call_policies.html#default_call_policies-spec">default_call_policies</a>.
<li>If <code>docstring</code> is supplied it must be an <a
href="definitions.html#ntbs">ntbs</a>, and will be used as the result's docstring. Otherwise the result has an empty docstring.
<li>If <code>keywords</code> is supplied it must be the result of a <a
href= "args.html#keyword-expression">keyword-expression</a>
whose length is no greater than <code>X</code>'s maximum
arity, and will be used as the result's keywords. Otherwise
the result's keywords will be empty.
</ul>
<h2><a name="macros"></a>Macros</h2>
<h3><a name=
"BOOST_PYTHON_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_FUNCTION_OVERLOADS(name, func_id, min_args, max_args)</a></h3>
Expands to the definition of an OverloadDispatcher called
<code>name</code> in the current scope which can be used to
generate the following function invocation:
<pre>
func_id(a<small><i>1</i></small>, a<small><i>2</i></small>,...a<small><i>i</i></small>);
</pre>
for all <code>min_args</code> <= <i>i</i> <= <code>max_args</code>.
<h3><a name=
"BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS-spec">BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(name, member_name, min_args, max_args)</a></h3>
Expands to the definition of an OverloadDispatcher called
<code>name</code> in the current scope which can be used to
generate the following function invocation:
<pre>
x.member_name(a<small><i>1</i></small>, a<small><i>2</i></small>,...a<small><i>i</i></small>);
</pre>
for all <code>min_args</code> <= <i>i</i> <=
<code>max_args</code>, where <code>x</code> is a reference to an
object of class type.
<h2><a name="examples"></a>Example(s)</h2>
<pre>
#include <boost/python/module.hpp>
#include <boost/python/def.hpp>
#include <boost/python/args.hpp>
#include <boost/python/tuple.hpp>
#include <boost/python/class.hpp>
#include <boost/python/overloads.hpp>
#include <boost/python/return_internal_reference.hpp>
using namespace boost::python;
tuple f(int x = 1, double y = 4.25, char const* z = "wow")
{
return make_tuple(x, y, z);
}
BOOST_PYTHON_FUNCTION_OVERLOADS(f_overloads, f, 0, 3)
struct Y {};
struct X
{
Y& f(int x, double y = 4.25, char const* z = "wow")
{
return inner;
}
Y inner;
};
BOOST_PYTHON_MEMBER_FUNCTION_OVERLOADS(f_member_overloads, f, 1, 3)
BOOST_PYTHON_MODULE(args_ext)
{
def("f", f,
f_overloads(
args("x", "y", "z"), "This is f's docstring"
));
class_<Y>("Y")
;
class_<X>("X", "This is X's docstring")
.def("f1", &X::f,
f_member_overloads(
args("x", "y", "z"), "f's docstring"
)[return_internal_reference<>()]
)
;
}
</pre>
<p>Revised
<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
15 April, 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>
|
