Python bindings for a vala library
- by celil
I am trying to create python bindings to a vala library using the following IBM tutorial as a reference.
My initial directory has the following two files:
test.vala
using GLib;
namespace Test {
public class Test : Object {
public int sum(int x, int y) {
return x + y;
}
}
}
test.override
%%
headers
#include <Python.h>
#include "pygobject.h"
#include "test.h"
%%
modulename test
%%
import gobject.GObject as PyGObject_Type
%%
ignore-glob
*_get_type
%%
and try to build the python module source test_wrap.c using the following code
build.sh
#/usr/bin/env bash
valac test.vala -CH test.h
python /usr/share/pygobject/2.0/codegen/h2def.py test.h > test.defs
pygobject-codegen-2.0 -o test.override -p test test.defs > test_wrap.c
However, the last command fails with an error
$ ./build.sh
Traceback (most recent call last):
File "/usr/share/pygobject/2.0/codegen/codegen.py", line 1720, in <module>
sys.exit(main(sys.argv))
File "/usr/share/pygobject/2.0/codegen/codegen.py", line 1672, in main
o = override.Overrides(arg)
File "/usr/share/pygobject/2.0/codegen/override.py", line 52, in __init__
self.handle_file(filename)
File "/usr/share/pygobject/2.0/codegen/override.py", line 84, in handle_file
self.__parse_override(buf, startline, filename)
File "/usr/share/pygobject/2.0/codegen/override.py", line 96, in __parse_override
command = words[0]
IndexError: list index out of range
Is this a bug in pygobject, or is something wrong with my setup? What is the best way to call code written in vala from python?
EDIT:
Removing the extra line fixed the current problem, but now as I proceed to build the python module, I am facing another problem. Adding the following C file to the existing two in the directory:
test_module.c
#include <Python.h>
void test_register_classes (PyObject *d);
extern PyMethodDef test_functions[];
DL_EXPORT(void)
inittest(void)
{
PyObject *m, *d;
init_pygobject();
m = Py_InitModule("test", test_functions);
d = PyModule_GetDict(m);
test_register_classes(d);
if (PyErr_Occurred ()) {
Py_FatalError ("can't initialise module test");
}
}
and building with the following script
build.sh
#/usr/bin/env bash
valac test.vala -CH test.h
python /usr/share/pygobject/2.0/codegen/h2def.py test.h > test.defs
pygobject-codegen-2.0 -o test.override -p test test.defs > test_wrap.c
CFLAGS="`pkg-config --cflags pygobject-2.0` -I/usr/include/python2.6/ -I."
LDFLAGS="`pkg-config --libs pygobject-2.0`"
gcc $CFLAGS -fPIC -c test.c
gcc $CFLAGS -fPIC -c test_wrap.c
gcc $CFLAGS -fPIC -c test_module.c
gcc $LDFLAGS -shared test.o test_wrap.o test_module.o -o test.so
python -c 'import test; exit()'
results in an error:
$ ./build.sh
***INFO*** The coverage of global functions is 100.00% (1/1)
***INFO*** The coverage of methods is 100.00% (1/1)
***INFO*** There are no declared virtual proxies.
***INFO*** There are no declared virtual accessors.
***INFO*** There are no declared interface proxies.
Traceback (most recent call last):
File "<string>", line 1, in <module>
ImportError: ./test.so: undefined symbol: init_pygobject
Where is the init_pygobject symbol defined? What have I missed linking to?
