Constant variable and API

[mg]

Hi everybody...

I am using Python API in order to create bindings.
So, in the init function of my module, I create constants :

PyMODINIT_FUNC initMyModule( void )
{
PyObject* module = Py_InitModule3( "MyModule", 0, "this is my
module" ) ;
if( ! module ) return ;

PyObject* dict = PyModule_GetDic t( module ) ;
if( ! dict ) return ;

long value = 0 ; // for the example
PyObject* py_value = PyInt_FromLong( value ) ;
char* name = "NULL" ;
PyDict_SetItemS tring( dict, name, py_value ) ;
Py_DECREF( py_value ) ;
}

So, my first "problem" is that my module variable is mutable; I can
write the following instruction in python :
[color=blue][color=green][color=darkred]
>>> import MyModule
>>> null = MyModule.NULL
>>> print null[/color][/color][/color]
0[color=blue][color=green][color=darkred]
>>> MyModule.NULL = 99
>>> null = MyModule.NULL
>>> print null[/color][/color][/color]
99

Then, my question is : how can I implement a constant variable from the
API in order to the reaffectation (MyModule.NULL = 99) of my variable be
impossible ?

Thanks for your help.
Mathieu

[Alex Martelli]

Re: Constant variable and API

mg <mg.mailing-list@laposte.ne t> wrote:
...[color=blue]
> Then, my question is : how can I implement a constant variable from the
> API in order to the reaffectation (MyModule.NULL = 99) of my variable be
> impossible ?[/color]

With a module (a direct instance of types.ModuleTyp e), you can't -- the
module type just doesn't have any functionality to control attribute
setting. You can subclass the type to do that, and install an instance
of the subclass in sys.modules in the appropriate place...


Alex