[C++-sig] pyCXX example of a callback

[apocalypznow]

I gave up on Boost.  Never could get it to build no matter what I did.
Thanks anyway, but I'm looking for a pyCXX solution.



Stefan Seefeld wrote:
> apocalypznow wrote:
> 
>>Hi,
>>
>>Can anyone post a simple pyCXX example of a callback into python?  My 
> 
> 
> I don't know what 'pyCXX' is, so let's assume you mean boost.python.
> 
> 
>>python function should allow a string passed as a parameter, and returns 
>>a string, ie:
>>
>>def somepythonCB(s_in):
>>     s_out = dosomethingtoinputstringandreturnoutputstring(s_in)
>>     return s_out
> 
> 
> The answer is very similar to one I gave in a previous question:
> 
> namespace bpl = boost::python;
> bpl::dict global;
> bpl::exec_file("your_file.py", global, global);      // load the definition
> bpl::object func = global["somepythonCP"];           // extract python function
> bpl::object retn = func(input);                      // call it with input string
> std::string value = bpl::extract<std::string>(retn); // extract return value
> 
> The magic here is that boost.python already has builtin support for
> conversion between std::string and python's str.
> Please note that the 'exec_file' function is only in CVS, not in the last
> official release. See my previous posts for more on that.
> 
> HTH,
> 		Stefan
>