boost_1_45_0/libs/python/doc/v2/data_members.html - nest-learning-thermostat/5.0/boost - Git at Google

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           <h1 align="center"><a href="../index.html">Boost.Python</a></h1>

           <h2 align="center">Header
           &lt;boost/python/data_members.hpp&gt;</h2>
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     <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_&lt;&gt;::<a href=
     "class.html#class_-spec-modifiers">def_readonly</a></code> and
     <code>class_&lt;&gt;::<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 &lt;class C, class D&gt;</a>
 <a href="object.html#object-spec">object</a> make_getter(D C::*pm);

 template &lt;class C, class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_getter(D C::*pm, Policies const&amp; 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>&lt;&gt;</code></dt>

       <dt>for <code>Policies</code>. Note that this test may inappropriately
       choose <code>return_internal_reference&lt;&gt;</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 &lt;class D&gt;
 <a href="object.html#object-spec">object</a> make_getter(D const&amp; d);
 template &lt;class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_getter(D const&amp; d, Policies const&amp; policies);

 template &lt;class D&gt;
 <a href="object.html#object-spec">object</a> make_getter(D const* p);
 template &lt;class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_getter(D const* p, Policies const&amp; 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 &lt;class C, class D&gt;</a>
 <a href="object.html#object-spec">object</a> make_setter(D C::*pm);

 template &lt;class C, class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_setter(D C::*pm, Policies const&amp; 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&nbsp;const&amp;</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 &lt;class D&gt;
 <a href="object.html#object-spec">object</a> make_setter(D&amp; d);
 template &lt;class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_setter(D&amp; d, Policies const&amp; policies);

 template &lt;class D&gt;
 <a href="object.html#object-spec">object</a> make_setter(D* p);
 template &lt;class D, class Policies&gt;
 <a href=
 "object.html#object-spec">object</a> make_setter(D* p, Policies const&amp; 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&amp;</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 &lt;boost/python/data_members.hpp&gt;
 #include &lt;boost/python/module.hpp&gt;
 #include &lt;boost/python/class.hpp&gt;

 struct X
 {
     X(int x) : y(x) {}
     int y;
 };

 using namespace boost::python;

 BOOST_PYTHON_MODULE_INIT(data_members_example)
 {
     class_&lt;X&gt;("X", init&lt;int&gt;())
        .def("get", make_getter(&amp;X::y))
        .def("set", make_setter(&amp;X::y))
        ;
 }
 </pre>
     It can be used this way in Python:
 <pre>
 &gt;&gt;&gt; from data_members_example import *
 &gt;&gt;&gt; x = X(1)
 &gt;&gt;&gt; x.get()
 1
 &gt;&gt;&gt; x.set(2)
 &gt;&gt;&gt; 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>&copy; Copyright <a href=
     "http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p>
   </body>
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	<!-- Copyright David Abrahams 2006. Distributed under the Boost -->
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	<body>
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	"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>