On 03/14/2013 06:12 PM, Neal Becker wrote:
I'm expecting a numpy.random.RandomState object to be passed to me. I want to
check it is. The best I could think of is below. Anything more boost::python-
ish to do this task?
static object rs_obj;
template<typename out_type=uint32_t>
struct engine {
typedef out_type result_type;
bp::object rs; // RandomState object
void verify (object const& o) {
if (!PyObject_IsInstance(o.ptr(), rs_obj.ptr()))
throw std::runtime_error ("engine: expected RandomState");
}
engine (bp::object const& _rs) : rs (_rs) { verify (_rs); }
...
BOOST_PYTHON_MODULE...
object mod = object (handle<> ((PyImport_ImportModule("numpy.random"))));
rs_obj = mod.attr("RandomState");
I believe you can replace the penultimate line with:
bp::object mod = bp::import("numpy.random");
But I can't think of any ways to Boost.Python-ize the rest; there really should be an
"isinstance" wrapper in Boost.Python, but there isn't. You may also want to be
a little careful with the return value of PyObject_IsInstance - I believe that it's
psosible for it to raise an exception instead of simply returning 0, and in that case
you'd want to use bp::throw_error_already_set() to propagate the exception to Python.
Jim
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