Module for python3.6.2 (Spyder environment) from c source code - c

Question

I'm quite new to python that I always use by writing script in spyder and running them in its Ipython console with python3.6.2 .
I'm trying to write a simple module from a "swig_example.c" file following a couple of swig tutorial (http://www.swig.org/tutorial.html, http://www.swig.org/Doc1.3/Python.html#Python_nn6).
My aim is to be able to run a script "main_python.py" which should look like:
import swig_test
print(swig_test.fact(4))
where fact is a function defined in the original c source.
The source file is "swig_example.c":
/* File: swig_example.c */
#include "swig_example.h"
int fact(int n) {
if (n == 0) {
return 1;
}
else {
return n * fact(n-1);
}
}
The header file is as simple as:
/* File: swig_example.h */
int fact(int n);
and the interface one:
/* File: swig_example.i */
%module swig_test
%{
#include "swig_example.h"
%}
%include "swig_example.h"
When in the terminal I run:
swig -python swig_example.i
a "swig_example_wrap.c" and a "swig_test.py" files are created.
How should I proceed to have my "main_python.py" working?
(It now returns a "No module named '_swig_test' error).
I would like to have some script (maybe using distutils?) so that each time I modify the .c source I can easily update the module without changing the "main_python.py" file.
If you have any solution which uses Xcode instead of spyder it would be well accepted.
I think that the question could be useful to many that are new to python (and Mac actually...) and try to use it while not throwing away their previous works...
EDIT:
I -partially- solved the problem. Now the main point remain Spyder.
I create the files ".c", ".h" and ".i" the way I described. Then, following this post (Python.h not found using swig and Anaconda Python) I create, in the same folder, my "setup.py" file:
from distutils.core import setup, Extension
example_module = Extension('_example', sources=['example.c','example.i'])
setup(name='example', ext_modules=[example_module], py_modules= .["example"])
Then, In anaconda navigator I open the terminal of the environment I'm working in, move to the right folder and run:
python setup.py build_ext --inplace
If now I open spyder everything works the desired way. But If I now want to modify my C source, say add a new function, problems arises. I modify the ".c", ".h" and ".i" files annd thenn re-run in the terminal the previous line. The "example.py" file result to e correctly modified (it innncludes the attribute of the new function), but when try to import the module in spyder (import example) changes are nnot registered and an error message "_example has no attribute "new function" is given in the Ipython console unless I restart Spyder itself.
Is there faster way to fix it? (maybe this is the interaction mentioned in the comments... )
Thank you all :-)