On 29.01.2016 13:15, Liam Herron wrote:
>
> For the following code:
>
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> #include <boost/python.hpp>
>
> using namespace boost::python;
>
>
>
> namespace // unnamed
>
> {
>
>
>
> class NullableDouble
>
> {
>
> public:
>
> NullableDouble()
>
> : isNull_(true)
>
> , value_(0.0)
>
> {
>
> }
>
>
>
> NullableDouble(double x)
>
> : isNull_(false)
>
> , value_(x)
>
> {
>
> }
>
>
>
> double value() const
>
> {
>
> return value_; // null check not relevant to this example
>
> }
>
>
>
> bool isNull() const
>
> {
>
> return isNull_;
>
> }
>
>
>
> // ... more functions but not needed for this example
>
>
>
> private:
>
> bool isNull_;
>
> double value_;
>
> };
>
>
>
> } // end namespace unnamed
>
>
>
> void init_pnic()
>
> {
>
> class_<NullableDouble>
>
> ("NullableDouble", "NullableDouble", init<>())
>
> .def(init<double>())
>
> .def("value", &NullableDouble::value)
>
> .def("isNull", &NullableDouble::isNull)
>
> ;
>
> }
>
>
>
> BOOST_PYTHON_MODULE(_testPNIC)
>
> {
>
> init_pnic();
>
> }
>
> -----------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
>
>
> I would like to have another constructor method in python that takes a
> ‘None’ and returns the same as the no arg constructor ‘NullableDouble()’
>
Just create a 'factory' function that takes a Python object (and which
you then check for None) to instantiate and return a "null". Add that
function to your wrapper like any other method (using '__init__' and
'make_constructor').
HTH,
Stefan
>
>
> What is the best way to do this?
>
>
>
> Thanks,
>
> --Liam
>
>
>
>
>
--
...ich hab' noch einen Koffer in Berlin...
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