Boost.Python create extra functions not in wrapped object

[Roman Yakovenko]

On 19 Apr 2007 00:37:36 -0700, Stou Sandalski <stou.sandalski at gmail.com>
wrote:
>
> Hi,
>
> I have a python library created by wrapping the C++ library using
> Boost.Python, the problem is that the wrappers are not very
> pythonic.... so I want to add some methods that do not exist in the C+
> + implementation, that would create a better Python interface.
>
> For example to initialize the data in an object in the library one
> must iterate through every point, setting a value for each
> individually.  That's the way it works in C++ but in python it would
> be nice to instead just have one call that can receive a numpy array
> or a tuple. I want to add a call like: setData(array) to the python
> object, a call that does not exist in the C++ implementation and then
> in the C++ wrappers actually use setData to iterate through the array
> and set the values using the normal C++ method, say setValue(index,
> value).
>
> Something along the lines of this (initData is not in the constructor
> on purpose) C++ object:
>
> class Foo
> {
> public:
>      void initData(int size)
>      {
>         data = new float[size];
>      }; // Create the data array
>      void setValue(int index, float value) // Set given value
>      {
>          data[index] = value;
>      }
> private:
>      float *data;
> };
>
>
> In python however I want to do this:
>
> obj = foo()
> ar = array([1,2,3,4,5], dtype=float)
>
> foo.setData(ar)
>
> Or even better:
>
> ar = array([1,2,3,4,5], dtype=float)
> obj = foo(ar)
>
> And have it somehow call initData() and setValue() iteration inside
> the C++ code of the wrapper.  I've only used SWIG and don't really
> know much about Boost, I am not even sure how to label what I am
> trying to do.
>
> Can this be done with Boost, without changing the C++ library?


Take a look on next link:
http://boost.org/libs/python/doc/tutorial/doc/html/python/techniques.html#python.extending_wrapped_objects_in_python

Regards,
>
> Stou
>
> --
> http://mail.python.org/mailman/listinfo/python-list
>



-- 
Roman Yakovenko
C++ Python language binding
http://www.language-binding.net/
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