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source: downloads/boost_1_34_1/libs/python/doc/v2/object.html @ 45

Last change on this file since 45 was 29, checked in by landauf, 17 years ago
updated boost from 1_33_1 to 1_34_1
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1	<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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3	<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
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13	<title>Boost.Python - <boost/python/object.hpp></title>
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15
16	<body>
17	<table border="0" cellpadding="7" cellspacing="0" width="100%" summary=
18	"header">
19	<tr>
20	<td valign="top" width="300">
21	<h3><a href="../../../../index.htm"><img height="86" width="277"
22	alt="C++ Boost" src="../../../../boost.png" border="0"></a></h3>
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24
25	<td valign="top">
26	<h1 align="center"><a href="../index.html">Boost.Python</a></h1>
27
28	<h2 align="center">Header <boost/python/object.hpp></h2>
29	</td>
30	</tr>
31	</table>
32	<hr>
33
34	<h2>Contents</h2>
35
36	<dl class="page-index">
37	<dt><a href="#introduction">Introduction</a></dt>
38
39	<dt><a href="#types">Types</a></dt>
40
41	<dd>
42	<dl class="page-index">
43	<dt><a href="#slice_nil-spec">slice_nil</a></dt>
44	</dl>
45	</dd>
46
47	<dt><a href="#classes">Classes</a></dt>
48
49	<dd>
50	<dl class="page-index">
51	<dt><a href="#const_attribute_policies-spec">Class
52	<code>const_attribute_policies</code></a></dt>
53
54	<dd>
55	<dl class="page-index">
56	<dt><a href="#const_attribute_policies-spec-synopsis">Class
57	<code>const_attribute_policies</code> synopsis</a></dt>
58
59	<dt><a href="#const_attribute_policies-spec-statics">Class
60	<code>const_attribute_policies</code> static functions</a></dt>
61	</dl>
62	</dd>
63
64	<dt><a href="#attribute_policies-spec">Class
65	<code>attribute_policies</code></a></dt>
66
67	<dd>
68	<dl class="page-index">
69	<dt><a href="#attribute_policies-spec-synopsis">Class
70	<code>attribute_policies</code> synopsis</a></dt>
71
72	<dt><a href="#attribute_policies-spec-statics">Class
73	<code>attribute_policies</code> static functions</a></dt>
74	</dl>
75	</dd>
76
77	<dt><a href="#const_item_policies-spec">Class
78	<code>const_item_policies</code></a></dt>
79
80	<dd>
81	<dl class="page-index">
82	<dt><a href="#const_item_policies-spec-synopsis">Class
83	<code>const_item_policies</code> synopsis</a></dt>
84
85	<dt><a href="#const_item_policies-spec-statics">Class
86	<code>const_item_policies</code> static functions</a></dt>
87	</dl>
88	</dd>
89
90	<dt><a href="#item_policies-spec">Class
91	<code>item_policies</code></a></dt>
92
93	<dd>
94	<dl class="page-index">
95	<dt><a href="#item_policies-spec-synopsis">Class
96	<code>item_policies</code> synopsis</a></dt>
97
98	<dt><a href="#item_policies-spec-statics">Class
99	<code>item_policies</code> static functions</a></dt>
100	</dl>
101	</dd>
102
103	<dt><a href="#const_slice_policies-spec">Class
104	<code>const_slice_policies</code></a></dt>
105
106	<dd>
107	<dl class="page-index">
108	<dt><a href="#const_slice_policies-spec-synopsis">Class
109	<code>const_slice_policies</code> synopsis</a></dt>
110
111	<dt><a href="#const_slice_policies-spec-statics">Class
112	<code>const_slice_policies</code> static functions</a></dt>
113	</dl>
114	</dd>
115
116	<dt><a href="#slice_policies-spec">Class
117	<code>slice_policies</code></a></dt>
118
119	<dd>
120	<dl class="page-index">
121	<dt><a href="#slice_policies-spec-synopsis">Class
122	<code>slice_policies</code> synopsis</a></dt>
123
124	<dt><a href="#slice_policies-spec-statics">Class
125	<code>slice_policies</code> static functions</a></dt>
126	</dl>
127	</dd>
128
129	<dt><a href="#object_operators-spec">Class
130	<code>object_operators</code></a></dt>
131
132	<dd>
133	<dl class="page-index">
134	<dt><a href="#object_operators-spec-synopsis">Class
135	<code>object_operators</code> synopsis</a></dt>
136
137	<dt><a href="#object_operators-spec-observers">Class
138	<code>object_operators</code> observer functions</a></dt>
139	</dl>
140	</dd>
141
142	<dt><a href="#object-spec">Class <code>object</code></a></dt>
143
144	<dd>
145	<dl class="page-index">
146	<dt><a href="#object-spec-synopsis">Class <code>object</code>
147	synopsis</a></dt>
148
149	<dt><a href="#object-spec-ctors">Class <code>object</code>
150	constructors and destructor</a></dt>
151
152	<dt><a href="#object-spec-modifiers">Class template
153	<code>object</code> modifier functions</a></dt>
154
155	<dt><a href="#object-spec-observers">Class template
156	<code>object</code> observer functions</a></dt>
157	</dl>
158	</dd>
159
160	<dt><a href="#proxy-spec">Class template
161	<code>proxy</code></a></dt>
162
163	<dd>
164	<dl class="page-index">
165	<dt><a href="#proxy-spec-synopsis">Class template
166	<code>proxy</code> synopsis</a></dt>
167
168	<dt><a href="#proxy-spec-modifiers">Class template
169	<code>proxy</code> modifier functions</a></dt>
170
171	<dt><a href="#proxy-spec-observers">Class template
172	<code>proxy</code> observer functions</a></dt>
173	</dl>
174	</dd>
175	</dl>
176	</dd>
177
178	<dt><a href="#functions">Functions</a></dt>
179
180	<dd>
181	<dl class="page-index">
182	<dt><a href="#del-spec">del</a></dt>
183
184	<dt><a href="#comparisons-spec">comparisons</a></dt>
185
186	<dt><a href="#binary-spec">binary operations</a></dt>
187
188	<dt><a href="#assignment-spec">assignment operations</a></dt>
189
190	</dl>
191
192	<dl class="page-index">
193	<dt><a href="#object_operators-spec">operators</a></dt>
194	</dl>
195
196	<dl class="page-index">
197	<dt><a href="#len-spec">len()</a></dt>
198	</dl>
199	</dd>
200
201	<dt><a href="#examples">Example</a></dt>
202	</dl>
203	<hr>
204
205	<h2><a name="introduction"></a>Introduction</h2>
206
207	<p>Exposes the generic Python object wrapper class <code>object</code>,
208	and related classes. In order to avoid some potenential problems with
209	argument-dependent lookup and the generalized operators defined on
210	<code>object</code>, all these facilities are defined in
211	<code>namespace boost::python::api</code>, and <code>object</code>
212	is imported into <code>namespace boost::python</code> with a
213	<i>using-declaration</i>.</p>
214
215	<h2><a name="types"></a>Types</h2>
216
217	<p><a name="slice_nil-spec"></a></p>
218	<pre>
219	class slice_nil;
220	static const _ = slice_nil();
221	</pre>
222	A type that can be used to get the effect of leaving out an index in a
223	Python slice expression:
224	<pre>
225	>>> x[:-1]
226	>>> x[::-1]
227	</pre>
228	C++ equivalent:
229	<pre>
230	x.slice(_,-1)
231	x[slice(_,_,-1)]
232	</pre>
233
234	<h2><a name="classes"></a>Classes</h2>
235	<!-- begin -->
236
237	<h3><a name="const_attribute_policies-spec"></a>Class
238	<code>const_attribute_policies</code></h3>
239
240	<p>The policies which are used for proxies representing an attribute
241	access to a <code>const object</code>.</p>
242
243	<h4><a name="const_attribute_policies-spec-synopsis"></a>Class
244	<code>const_attribute_policies</code> synopsis</h4>
245	<pre>
246	namespace boost { namespace python { namespace api
247	{
248	struct const_attribute_policies
249	{
250	typedef char const* key_type;
251	static object get(object const& target, char const* key);
252	};
253	}}}
254	</pre>
255
256	<h4><a name="const_attribute_policies-spec-statics"></a>Class
257	<code>const_attribute_policies</code> static functions</h4>
258	<pre>
259	static object get(object const& target, char const* key);
260	</pre>
261
262	<dl class="function-semantics">
263	<dt><b>Requires:</b> <code>key</code> is an <a href=
264	"definitions.html#ntbs">ntbs</a>.</dt>
265
266	<dt><b>Effects:</b> accesses the attribute of <code>target</code> named
267	by <code>key</code>.</dt>
268
269	<dt><b>Returns:</b> An <code>object</code> managing the result of the
270	attribute access.</dt>
271
272	<dt><b>Throws:</b> <code><a href=
273	"errors.html#error_already_set-spec">error_already_set</a></code> if a
274	Python exception is raised.</dt>
275	</dl>
276
277	<h3><a name="attribute_policies-spec"></a>Class
278	<code>attribute_policies</code></h3>
279
280	<p>The policies which are used for proxies representing an attribute
281	access to a mutable <code>object</code>.</p>
282
283	<h4><a name="attribute_policies-spec-synopsis"></a>Class
284	<code>attribute_policies</code> synopsis</h4>
285	<pre>
286	namespace boost { namespace python { namespace api
287	{
288	struct attribute_policies : const_attribute_policies
289	{
290	static object const& set(object const& target, char const* key, object const& value);
291	static void del(object const&target, char const* key);
292	};
293	}}}
294	</pre>
295
296	<h4><a name="attribute_policies-spec-statics"></a>Class
297	<code>attribute_policies</code> static functions</h4>
298	<pre>
299	static object const& set(object const& target, char const* key, object const& value);
300	</pre>
301
302	<dl class="function-semantics">
303	<dt><b>Requires:</b> <code>key</code> is an <a href=
304	"definitions.html#ntbs">ntbs</a>.</dt>
305
306	<dt><b>Effects:</b> sets the attribute of <code>target</code> named by
307	<code>key</code> to <code>value</code>.</dt>
308
309	<dt><b>Throws:</b> <code><a href=
310	"errors.html#error_already_set-spec">error_already_set</a></code> if a
311	Python exception is raised.</dt>
312	</dl>
313	<pre>
314	static void del(object const&target, char const* key);
315	</pre>
316
317	<dl class="function-semantics">
318	<dt><b>Requires:</b> <code>key</code> is an <a href=
319	"definitions.html#ntbs">ntbs</a>.</dt>
320
321	<dt><b>Effects:</b> deletes the attribute of <code>target</code> named
322	by <code>key</code>.</dt>
323
324	<dt><b>Throws:</b> <code><a href=
325	"errors.html#error_already_set-spec">error_already_set</a></code> if a
326	Python exception is raised.</dt>
327	</dl>
328	<!-- end -->
329	<!-- begin -->
330
331	<h3><a name="const_item_policies-spec"></a>Class
332	<code>const_item_policies</code></h3>
333
334	<p>The policies which are used for proxies representing an item access
335	(via the Python bracket operators <code>[]</code>) to a
336	<code>const object</code>.</p>
337
338	<h4><a name="const_item_policies-spec-synopsis"></a>Class
339	<code>const_item_policies</code> synopsis</h4>
340	<pre>
341	namespace boost { namespace python { namespace api
342	{
343	struct const_item_policies
344	{
345	typedef object key_type;
346	static object get(object const& target, object const& key);
347	};
348	}}}
349	</pre>
350
351	<h4><a name="const_item_policies-spec-statics"></a>Class
352	<code>const_item_policies</code> static functions</h4>
353	<pre>
354	static object get(object const& target, object const& key);
355	</pre>
356
357	<dl class="function-semantics">
358	<dt><b>Effects:</b> accesses the item of <code>target</code> specified
359	by <code>key</code>.</dt>
360
361	<dt><b>Returns:</b> An <code>object</code> managing the result of the
362	item access.</dt>
363
364	<dt><b>Throws:</b> <code><a href=
365	"errors.html#error_already_set-spec">error_already_set</a></code> if a
366	Python exception is raised.</dt>
367	</dl>
368
369	<h3><a name="item_policies-spec"></a>Class
370	<code>item_policies</code></h3>
371
372	<p>The policies which are used for proxies representing an item access
373	(via the Python bracket operators <code>[]</code>) to a mutable
374	<code>object</code>.</p>
375
376	<h4><a name="item_policies-spec-synopsis"></a>Class
377	<code>item_policies</code> synopsis</h4>
378	<pre>
379	namespace boost { namespace python { namespace api
380	{
381	struct item_policies : const_item_policies
382	{
383	static object const& set(object const& target, object const& key, object const& value);
384	static void del(object const& target, object const& key);
385	};
386	}}}
387	</pre>
388
389	<h4><a name="item_policies-spec-statics"></a>Class
390	<code>item_policies</code> static functions</h4>
391	<pre>
392	static object const& set(object const& target, object const& key, object const& value);
393	</pre>
394
395	<dl class="function-semantics">
396	<dt><b>Effects:</b> sets the item of <code>target</code> specified by
397	<code>key</code> to <code>value</code>.</dt>
398
399	<dt><b>Throws:</b> <code><a href=
400	"errors.html#error_already_set-spec">error_already_set</a></code> if a
401	Python exception is raised.</dt>
402	</dl>
403	<pre>
404	static void del(object const& target, object const& key);
405	</pre>
406
407	<dl class="function-semantics">
408	<dt><b>Effects:</b> deletes the item of <code>target</code> specified
409	by <code>key</code>.</dt>
410
411	<dt><b>Throws:</b> <code><a href=
412	"errors.html#error_already_set-spec">error_already_set</a></code> if a
413	Python exception is raised.</dt>
414	</dl>
415	<!-- end -->
416	<!-- begin -->
417
418	<h3><a name="const_slice_policies-spec"></a>Class
419	<code>const_slice_policies</code></h3>
420
421	<p>The policies which are used for proxies representing an slice access
422	(via the Python slice notation
423	<code>[</code><i>x</i><code>:</code><i>y</i><code>]</code>) to a
424	<code>const object</code>.</p>
425
426	<h4><a name="const_slice_policies-spec-synopsis"></a>Class
427	<code>const_slice_policies</code> synopsis</h4>
428	<pre>
429	namespace boost { namespace python { namespace api
430	{
431	struct const_slice_policies
432	{
433	typedef std::pair<handle<>, handle<> > key_type;
434	static object get(object const& target, key_type const& key);
435	};
436	}}}
437	</pre>
438
439	<h4><a name="const_slice_policies-spec-statics"></a>Class
440	<code>const_slice_policies</code> static functions</h4>
441	<pre>
442	static object get(object const& target, key_type const& key);
443	</pre>
444
445	<dl class="function-semantics">
446	<dt><b>Effects:</b> accesses the slice of <code>target</code> specified
447	by <code>key</code>.</dt>
448
449	<dt><b>Returns:</b> An <code>object</code> managing the result of the
450	slice access.</dt>
451
452	<dt><b>Throws:</b> <code><a href=
453	"errors.html#error_already_set-spec">error_already_set</a></code> if a
454	Python exception is raised.</dt>
455	</dl>
456
457	<h3><a name="slice_policies-spec"></a>Class
458	<code>slice_policies</code></h3>
459
460	<p>The policies which are used for proxies representing an slice access
461	to a mutable <code>object</code>.</p>
462
463	<h4><a name="slice_policies-spec-synopsis"></a>Class
464	<code>slice_policies</code> synopsis</h4>
465	<pre>
466	namespace boost { namespace python { namespace api
467	{
468	struct slice_policies : const_slice_policies
469	{
470	static object const& set(object const& target, key_type const& key, object const& value);
471	static void del(object const& target, key_type const& key);
472	};
473	}}}
474	</pre>
475
476	<h4><a name="slice_policies-spec-statics"></a>Class
477	<code>slice_policies</code> static functions</h4>
478	<pre>
479	static object const& set(object const& target, key_type const& key, object const& value);
480	</pre>
481
482	<dl class="function-semantics">
483	<dt><b>Effects:</b> sets the slice of <code>target</code> specified by
484	<code>key</code> to <code>value</code>.</dt>
485
486	<dt><b>Throws:</b> <code><a href=
487	"errors.html#error_already_set-spec">error_already_set</a></code> if a
488	Python exception is raised.</dt>
489	</dl>
490	<pre>
491	static void del(object const& target, key_type const& key);
492	</pre>
493
494	<dl class="function-semantics">
495	<dt><b>Effects:</b> deletes the slice of <code>target</code> specified
496	by <code>key</code>.</dt>
497
498	<dt><b>Throws:</b> <code><a href=
499	"errors.html#error_already_set-spec">error_already_set</a></code> if a
500	Python exception is raised.</dt>
501	</dl>
502	<!-- end -->
503
504	<h3><a name="object_operators-spec"></a>Class template
505	<code>object_operators<U></code></h3>
506
507	<p>This is the base class of <code>object</code> and its
508	<code>proxy</code> template used to supply common interface: member
509	functions, and operators which must be defined within the class body. Its
510	template parameter <code>U</code> is expected to be a class derived from
511	<code>object_operators<U></code>. In practice users should never
512	use this class directly, but it is documented here because it supplies
513	important interface to <code>object</code> and its proxies.</p>
514
515	<h4><a name="object_operators-spec-synopsis"></a>Class template
516	<code>object_operators</code> synopsis</h4>
517	<pre>
518	namespace boost { namespace python { namespace api
519	{
520	template <class U>
521	class object_operators
522	{
523	public:
524	// function call
525	//
526	object operator()() const;
527
528	template <class A0>
529	object operator()(A0 const&) const;
530	template <class A0, class A1>
531	object operator()(A0 const&, A1 const&) const;
532	...
533	template <class A0, class A1,...class An>
534	object operator()(A0 const&, A1 const&,...An const&) const;
535
536	// truth value testing
537	//
538	typedef unspecified bool_type;
539	operator bool_type() const;
540
541	// Attribute access
542	//
543	proxy<const_object_attribute> attr(char const*) const;
544	proxy<object_attribute> attr(char const*);
545
546	// item access
547	//
548	template <class T>
549	proxy<const_object_item> operator[](T const& key) const;
550
551	template <class T>
552	proxy<object_item> operator[](T const& key);
553
554	// slicing
555	//
556	template <class T, class V>
557	proxy<const_object_slice> slice(T const& start, V const& end) const
558
559	template <class T, class V>
560	proxy<object_slice> slice(T const& start, V const& end);
561	};
562	}}}
563	</pre>
564
565	<h4><a name="object_operators-spec-observers"></a>Class template
566	<code>object_operators</code> observer functions</h4>
567	<pre>
568	object operator()() const;
569	template <class A0>
570	object operator()(A0 const&) const;
571	template <class A0, class A1>
572	object operator()(A0 const&, A1 const&) const;
573	...
574	template <class A0, class A1,...class An>
575	object operator()(A0 const& a1, A1 const& a2,...An const& aN) const;
576	</pre>
577
578	<dl class="function-semantics">
579	<dt><b>Effects:</b>
580	call<object>(object(static_cast<U>(this)).ptr(), a1,
581	a2,...aN)</dt>
582	</dl>
583	<pre>
584	operator bool_type() const;
585	</pre>
586
587	<dl class="function-semantics">
588	<dt><b>Effects:</b> Tests truth value of <code>*this</code>.</dt>
589
590	<dt><b>Returns:</b>
591	call<object>(object(static_cast<U>(this)).ptr(), a1,
592	a2,...aN)</dt>
593	</dl>
594	<pre>
595	proxy<const_object_attribute> attr(char const* name) const;
596	proxy<object_attribute> attr(char const* name);
597	</pre>
598
599	<dl class="function-semantics">
600	<dt><b>Requires:</b> name is an <a href=
601	"definitions.html#ntbs">ntbs</a>.</dt>
602
603	<dt><b>Effects:</b> accesses the named attribute of
604	<code>*this</code>.</dt>
605
606	<dt><b>Returns:</b> a proxy object which binds
607	<code>object(static_cast<U>(this))</code> as its target, and
608	<code>name</code> as its key.</dt>
609	</dl>
610	<pre>
611	template <class T>
612	proxy<const_object_item> operator[](T const& key) const;
613	template <class T>
614	proxy<object_item> operator[](T const& key);
615	</pre>
616
617	<dl class="function-semantics">
618	<dt><b>Effects:</b> accesses the item of <code>*this</code> indicated
619	by <code>key</code>.</dt>
620
621	<dt><b>Returns:</b> a proxy object which binds
622	<code>object(static_cast<U>(this))</code> as its target, and
623	<code>object(key)</code> as its key.</dt>
624	</dl>
625	<pre>
626	template <class T, class V>
627	proxy<const_object_slice> slice(T const& start; start, V const& finish) const
628	template <class T, class V>
629	proxy<object_slice> slice(T const& start; start, V const& finish);
630	</pre>
631
632	<dl class="function-semantics">
633	<dt><b>Effects:</b> accesses the slice of <code>*this</code> indicated
634	by <code>std::make_pair(object(start), object(finish))</code>.</dt>
635
636	<dt><b>Returns:</b> a proxy object which binds
637	<code>object(static_cast<U>(this))</code> as its target, and
638	<code>std::make_pair(object(start), object(finish))</code> as its
639	key.</dt>
640	</dl>
641	<!-- -->
642
643	<h3><a name="object-spec"></a>Class <code>object</code></h3>
644
645	<p>The intention is that <code>object</code> acts as much like a
646	Python variable as possible. Thus expressions you'd expect to work
647	in Python should generally work in the same way from C++. Most of
648	<code>object</code>'s interface is provided by its base class
649	<code><a
650	href="#object_operators-spec">object_operators</a><object></code>,
651	and the <a href="#functions">free functions</a> defined in this
652	header.
653	</p>
654
655	<h4><a name="object-spec-synopsis"></a>Class <code>object</code>
656	synopsis</h4>
657	<pre>
658	namespace boost { namespace python { namespace api
659	{
660	class object : public object_operators<object>
661	{
662	public:
663	object();
664
665	object(object const&);
666
667	template <class T>
668	explicit object(T const& x);
669
670	~object();
671
672	object& operator=(object const&);
673
674	PyObject* ptr() const;
675	};
676	}}}
677	</pre>
678
679	<h4><a name="object-spec-ctors"></a>Class <code>object</code>
680	constructors and destructor</h4>
681	<pre>
682	object();
683	</pre>
684
685	<dl class="function-semantics">
686	<dt><b>Effects:</b> Constructs an object managing a reference to the
687	Python <code>None</code> object.</dt>
688
689	<dt><b>Throws:</b> nothing.</dt>
690	</dl>
691	<pre>
692	template <class T>
693	explicit object(T const& x);
694	</pre>
695
696	<dl class="function-semantics">
697	<dt><b>Effects:</b> converts <code>x</code> to python and manages a
698	reference to it.</dt>
699
700	<dt><b>Throws:</b> <code>error_already_set</code> and sets a Python
701	<code>TypeError</code> exception if no such conversion is
702	possible.</dt>
703	</dl>
704	<pre>
705	~object();
706	</pre>
707
708	<dl class="function-semantics">
709	<dt><b>Effects:</b> decrements the reference count of the
710	internally-held object.</dt>
711	</dl>
712
713	<h4><a name="object-spec-modifiers"></a>Class <code>object</code>
714	modifiers</h4>
715	<pre>
716	object& operator=(object const& rhs);
717	</pre>
718
719	<dl class="function-semantics">
720	<dt><b>Effects:</b> increments the reference count of the object held
721	by <code>rhs</code> and decrements the reference count of the object
722	held by <code>*this</code>.</dt>
723	</dl>
724
725	<h4><a name="object-spec-observers"></a>Class <code>object</code>
726	observers</h4>
727	<pre>
728	PyObject* ptr() const;
729	</pre>
730
731	<dl class="function-semantics">
732	<dt><b>Returns:</b> a pointer to the internally-held Python
733	object.</dt>
734	</dl>
735	<!-- -->
736
737	<h3><a name="proxy-spec"></a>Class template <code>proxy</code></h3>
738
739	<p>This template is instantiated with various Policies described in this
740	document in order to implement attribute, item, and slice access for
741	<code>object</code>. It stores an object of type
742	<code>Policies::key_type</code>.</p>
743
744	<h4><a name="proxy-spec-synopsis"></a>Class template <code>proxy</code>
745	synopsis</h4>
746	<pre>
747	namespace boost { namespace python { namespace api
748	{
749	template <class Policies>
750	class proxy : public object_operators<proxy<Policies> >
751	{
752	public:
753	operator object() const;
754
755	proxy const& operator=(proxy const&) const;
756	template <class T>
757	inline proxy const& operator=(T const& rhs) const;
758
759	void del() const;
760
761	template <class R>
762	proxy operator+=(R const& rhs);
763	template <class R>
764	proxy operator-=(R const& rhs);
765	template <class R>
766	proxy operator*=(R const& rhs);
767	template <class R>
768	proxy operator/=(R const& rhs);
769	template <class R>
770	proxy operator%=(R const& rhs);
771	template <class R>
772	proxy operator<<=(R const& rhs);
773	template <class R>
774	proxy operator>>=(R const& rhs);
775	template <class R>
776	proxy operator&=(R const& rhs);
777	template <class R>
778	proxy operator\|=(R const& rhs);
779	};
780	}}}
781	</pre>
782
783	<h4><a name="proxy-spec-observers"></a>Class template <code>proxy</code>
784	observer functions</h4>
785	<pre>
786	operator object() const;
787	</pre>
788
789	<dl class="function-semantics">
790	<dt><b>Effects:</b> applies
791	<code>Policies::get(</code><i>target</i><code>,</code> <i>key</i>
792	<code>)</code> with the proxy's target and key objects.</dt>
793	</dl>
794
795	<h4><a name="proxy-spec-modifiers"></a>Class template <code>proxy</code>
796	modifier functions</h4>
797	<pre>
798	proxy const& operator=(proxy const& rhs) const;
799	template <class T>
800	inline proxy const& operator=(T const& rhs) const;
801	</pre>
802
803	<dl class="function-semantics">
804	<dt><b>Effects:</b>
805	<code>Policies::set(</code><i>target</i><code>,</code> <i>key</i>
806	<code>, object(rhs))</code> with the proxy's target and key
807	objects.</dt>
808	</dl>
809	<pre>
810	template <class R>
811	proxy operator+=(R const& rhs);
812	template <class R>
813	proxy operator-=(R const& rhs);
814	template <class R>
815	proxy operator*=(R const& rhs);
816	template <class R>
817	proxy operator/=(R const& rhs);
818	template <class R>
819	proxy operator%=(R const& rhs);
820	template <class R>
821	proxy operator<<=(R const& rhs);
822	template <class R>
823	proxy operator>>=(R const& rhs);
824	template <class R>
825	proxy operator&=(R const& rhs);
826	template <class R>
827	proxy operator\|=(R const& rhs);
828	</pre>
829
830	<dl class="function-semantics">
831	<dt><b>Effects:</b> for a given operator@=,
832	<code>object(*this) @= rhs;</code></dt>
833	<dt><b>Returns:</b> <code>*this</code></dt>
834	</dl>
835	<pre>
836	void del() const;
837	</pre>
838
839	<dl class="function-semantics">
840	<dt><b>Effects:</b>
841	<code>Policies::del(</code><i>target</i><code>,</code> <i>key</i>
842	<code>)</code> with the proxy's target and key objects.</dt>
843	</dl>
844	<!-- -->
845
846	<h2><a name="functions"></a>Functions</h2>
847	<pre>
848	<a name="del-spec"></a>template <class T>
849	void del(proxy<T> const& x);
850	</pre>
851
852	<dl class="function-semantics">
853	<dt><b>Effects:</b> x.del()</dt>
854	</dl>
855	<pre>
856	<a name="comparisons-spec"></a>
857	template<class L,class R> object operator>(L const&l,R const&r);
858	template<class L,class R> object operator>=(L const&l,R const&r);
859	template<class L,class R> object operator<(L const&l,R const&r);
860	template<class L,class R> object operator<=(L const&l,R const&r);
861	template<class L,class R> object operator==(L const&l,R const&r);
862	template<class L,class R> object operator!=(L const&l,R const&r);
863	</pre>
864
865	<dl class="function-semantics">
866	<dt><b>Effects:</b> returns the result of applying the operator to
867	<code>object(l)</code> and <code>object(r)</code>, respectively, in
868	Python.</dt>
869	</dl>
870	<pre>
871	<a name="binary-spec"></a>
872	template<class L,class R> object operator+(L const&l,R const&r);
873	template<class L,class R> object operator-(L const&l,R const&r);
874	template<class L,class R> object operator*(L const&l,R const&r);
875	template<class L,class R> object operator/(L const&l,R const&r);
876	template<class L,class R> object operator%(L const&l,R const&r);
877	template<class L,class R> object operator<<(L const&l,R const&r);
878	template<class L,class R> object operator>>(L const&l,R const&r);
879	template<class L,class R> object operator&(L const&l,R const&r);
880	template<class L,class R> object operator^(L const&l,R const&r);
881	template<class L,class R> object operator\|(L const&l,R const&r);
882	</pre>
883
884	<dl class="function-semantics">
885	<dt><b>Effects:</b> returns the result of applying the operator to
886	<code>object(l)</code> and <code>object(r)</code>, respectively, in
887	Python.</dt>
888	</dl>
889	<pre>
890	<a name="assignment-spec"></a>
891	template<class R> object& operator+=(object&l,R const&r);
892	template<class R> object& operator-=(object&l,R const&r);
893	template<class R> object& operator*=(object&l,R const&r);
894	template<class R> object& operator/=(object&l,R const&r);
895	template<class R> object& operator%=(object&l,R const&r);
896	template<class R> object& operator<<=(object&l,R const&r)
897	template<class R> object& operator>>=(object&l,R const&r);
898	template<class R> object& operator&=(object&l,R const&r);
899	template<class R> object& operator^=(object&l,R const&r);
900	template<class R> object& operator\|=(object&l,R const&r);
901	</pre>
902
903	<dl class="function-semantics">
904	<dt><b>Effects:</b> assigns to l the result of applying the
905	corresponding Python inplace operator to <code>l</code> and
906	<code>object(r)</code>, respectively.</dt>
907
908	<dt><b>Returns:</b> <code>l</code>.</dt>
909	</dl>
910
911	<pre>
912	inline long len(object const& obj);
913	</pre>
914
915	<dl class="function-semantics">
916	<dt><b>Effects:</b> PyObject_Length(obj.ptr()) </dt>
917	<dt><b>Returns:</b> len() of object.</dt>
918	</dl>
919
920	<h2><a name="examples"></a>Example</h2>
921	Python code:
922	<pre>
923	def sum_items(seq):
924	result = 0
925	for x in seq:
926	result += x
927	return result
928	</pre>
929	C++ version:
930	<pre>
931	object sum_items(object seq)
932	{
933	object result = object(0);
934	for (int i = 0; i < len(seq); ++i)
935	result += seq[i];
936	return result;
937	}
938	</pre>
939	<p>Revised
940	<!--webbot bot="Timestamp" S-Type="EDITED" S-Format="%d %B, %Y" startspan -->
941	13 January, 2006
942	<!--webbot bot="Timestamp" endspan i-checksum="39359" -->
943	</p>
944
945	<p><i>© Copyright <a href=
946	"../../../../people/dave_abrahams.htm">Dave Abrahams</a> 2006.</i></p>
947	</body>
948	</html>

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