|
Boost.PythonHeader <boost/python/to_python_converter.hpp> |
to_python_converter
to_python_converter
synopsis
to_python_converter
constructor
to_python_converter
registers a conversion from
objects of a given C++ type into a Python object.
to_python_converter
to_python_converter
adds a wrapper around a static
member function of its second template parameter, handling
low-level details such as insertion into the converter registry.
Parameter | Requirements | Description |
---|---|---|
T
| The C++ type of the source object in the conversion | |
Conversion
| PyObject* p = Conversion::convert(x) ,if p == 0 , PyErr_Occurred() != 0 .
| A class type whose static member function
convert does the real work of the conversion.
|
to_python_converter
synopsisnamespace boost { namespace python { template <class T, class Conversion> struct to_python_converter { to_python_converter(); }; }}
to_python_converter
constructorto_python_converter();
Conversion::convert()
to do its work.
"noddy.h"
. Because
noddy_NoddyObject
is the ultimate trivial extension type,
the example is a bit contrived: it wraps a function for which all
information is contained in the type of its return value.
#include <boost/python/reference.hpp> #include <boost/python/module.hpp> #include "noddy.h" struct tag {}; tag make_tag() { return tag(); } using namespace boost::python; struct tag_to_noddy { static PyObject* convert(tag const& x) { return PyObject_New(noddy_NoddyObject, &noddy_NoddyType); } }; BOOST_PYTHON_MODULE_INIT(to_python_converter) { module to_python("to_python_converter") .def("make_tag", make_tag) ; to_python_converter<tag, tag_to_noddy>(); }
>>> import to_python_converter >>> def always_none(): ... return None ... >>> def choose_function(x): ... if (x % 2 != 0): ... return to_python_converter.make_tag ... else: ... return always_none ... >>> a = [ choose_function(x) for x in range(5) ] >>> b = [ f() for f in a ] >>> type(b[0]) <type 'NoneType'> >>> type(b[1]) <type 'Noddy'> >>> type(b[2]) <type 'NoneType'> >>> type(b[3]) <type 'Noddy'>
Revised 05 November, 2001
© Copyright Dave Abrahams 2002. All Rights Reserved.