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| <h1 align="center"><a href="../index.html">Boost.Python</a></h1> |
| |
| <h2 align="center">Header <boost/python/scope.hpp></h2> |
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| <hr> |
| |
| <h2>Contents</h2> |
| |
| <dl class="page-index"> |
| <dt><a href="#introduction">Introduction</a></dt> |
| |
| <dt><a href="#classes">Classes</a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#scope-spec">Class <code>scope</code></a></dt> |
| |
| <dd> |
| <dl class="page-index"> |
| <dt><a href="#scope-spec-synopsis">Class <code>scope</code> |
| synopsis</a></dt> |
| |
| <dt><a href="#scope-spec-ctors">Class <code>scope</code> |
| constructors and destructor</a></dt> |
| </dl> |
| </dd> |
| </dl> |
| </dd> |
| |
| <dt><a href="#examples">Example</a></dt> |
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| <hr> |
| |
| <h2><a name="introduction"></a>Introduction</h2> |
| |
| <p>Defines facilities for querying and controlling the Python scope |
| (namespace) which will contain new wrapped classes and functions.</p> |
| |
| <h2><a name="classes"></a>Classes</h2> |
| |
| <h3><a name="scope-spec"></a>Class <code>scope</code></h3> |
| |
| <p>The <code>scope</code> class has an associated global Python |
| object which controls the Python namespace in which new extension |
| classes and wrapped functions will be defined as |
| attributes. Default-constructing a new <code>scope</code> object |
| binds it to the associated global Python object. Constructing a |
| <code>scope</code> object with an argument changes the associated |
| global Python object to the one held by the argument, until the |
| lifetime of the <code>scope</code> object ends, at which time the |
| associated global Python object reverts to what it was before the |
| <code>scope</code> object was constructed.</p> |
| |
| <h4><a name="scope-spec-synopsis"></a>Class <code>scope</code> |
| synopsis</h4> |
| <pre> |
| namespace boost { namespace python |
| { |
| class scope : public <a href= |
| "object.html#object-spec">object</a> |
| { |
| public: |
| scope(scope const&); |
| scope(object const&); |
| scope(); |
| ~scope() |
| private: |
| void operator=(scope const&); |
| }; |
| }} |
| </pre> |
| |
| <h4><a name="scope-spec-ctors"></a>Class <code>scope</code> constructors |
| and destructor</h4> |
| <pre> |
| explicit scope(scope const& x); |
| explicit scope(object const& x); |
| </pre> |
| Stores a reference to the current associated scope object, and sets the |
| associated scope object to the one referred to by <code>x.ptr()</code>. |
| The <code>object</code> base class is initialized with <code>x</code>. |
| <pre> |
| scope(); |
| </pre> |
| Stores a reference to the current associated scope object. The |
| <code>object</code> base class is initialized with the current associated |
| scope object. Outside any module initialization function, the current |
| associated Python object is <code>None</code>. |
| <pre> |
| ~scope() |
| </pre> |
| Sets the current associated Python object to the stored object. |
| |
| <h2><a name="examples"></a>Example</h2> |
| The following example shows how scope setting can be used to define |
| nested classes. |
| |
| <p>C++ Module definition:</p> |
| <pre> |
| #include <boost/python/module.hpp> |
| #include <boost/python/class.hpp> |
| #include <boost/python/scope.hpp> |
| using namespace boost::python; |
| |
| struct X |
| { |
| void f() {} |
| |
| struct Y { int g() { return 42; } }; |
| }; |
| |
| BOOST_PYTHON_MODULE(nested) |
| { |
| // add some constants to the current (module) scope |
| scope().attr("yes") = 1; |
| scope().attr("no") = 0; |
| |
| // Change the current scope |
| scope outer |
| = class_<X>("X") |
| .def("f", &X::f) |
| ; |
| |
| // Define a class Y in the current scope, X |
| class_<X::Y>("Y") |
| .def("g", &X::Y::g) |
| ; |
| } |
| </pre> |
| Interactive Python: |
| <pre> |
| >>> import nested |
| >>> nested.yes |
| 1 |
| >>> y = nested.X.Y() |
| >>> y.g() |
| 42 |
| </pre> |
| |
| <p>Revised 09 October, 2002</p> |
| |
| <p><i>© Copyright <a href= |
| "http://www.boost.org/people/dave_abrahams.htm">Dave Abrahams</a> 2002.</i></p> |
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