Instantiate a python class object in C

[Dids]

Hi,

Apologies if this was asked before, I couldn't find anything.

I have a class defined in a python file:
for example:

class demo:
  [ class definition goes here]

I'm writing a C extension.
In the first function, I take an instance of the demo class and do
my magic. It's working, all is good.

What I can't figure out is how to create a second C function that
returns a new instance to the demo class to python.
There must a be tutorial somewhere, but I can't find anything. I do
not want to define a new python class in C.

Another example:
   This is working:
demo_obj1 = demo()
my_C_extension.function_1( demo_obj1 )  //working, all good.

   This I can't figure out how to do:
new_demo_obj = my_C_extension.function_2()

Thanks for reading,
Dids,
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Re: Instantiate a python class object in C

[Stefan Behnel]

Dids, 14.03.2012 14:46:
 Apologies if this was asked before, I couldn't find anything.
 
 I have a class defined in a python file:
 for example:
 
 class demo:
   [ class definition goes here]
 
 I'm writing a C extension.
 In the first function, I take an instance of the demo class and do
 my magic. It's working, all is good.
 
 What I can't figure out is how to create a second C function that
 returns a new instance to the demo class to python.
 There must a be tutorial somewhere, but I can't find anything. I do
 not want to define a new python class in C.
 
 Another example:
This is working:
 demo_obj1 = demo()
 my_C_extension.function_1( demo_obj1 )  //working, all good.
 
This I can't figure out how to do:
 new_demo_obj = my_C_extension.function_2()

You should consider giving Cython a try. It will allow you to write normal
Python code for your C extension that it translates to efficient C code.
This is much easier than writing all of this by hand, especially when it
comes to classes. It will also optimise the code for you, so that you'll
often end up with faster code than what you'd manually write.

Stefan

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Re: Instantiate a python class object in C

[Dids]

Ok, I have it :)

PyImport_Import , PyModule_GetDict, PyDict_GetItemString and
PyObject_CallObject

Need to take a second look at cython when I have a spare cycle or 2.

Thanks for the the tip :)

A+
Dids,

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