From gagsl-py2 at yahoo.com.ar  Fri Jan  8 17:45:02 2010
From: gagsl-py2 at yahoo.com.ar (Gabriel Genellina)
Date: Fri, 8 Jan 2010 08:45:02 -0800 (PST)
Subject: [capi-sig] Create instance given its type
Message-ID: <445773.22325.qm@web32803.mail.mud.yahoo.com>

Hello

I want to create an instance given its type object. I expected that calling the type would be enough, something like this:

obj = (MyFooObject *) PyObject_CallFunctionObjArgs(&MyFooType, other, arguments, NULL)

but it doesn't work (nor even compiles, I think). So this is what I'm doing now:

obj = (MyFooObject *) PyObject_CallMethod((PyObject *)&PyType_Type, "__call__", "OOO", &MyFooType, other, arguments);

where MyFooType is a PyTypeObject struct. Ok, it works, but I'm pretty sure there is a more direct way - but how?

Thanks,
-- 
Gabriel Genellina


      Yahoo! Cocina

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http://ar.mujer.yahoo.com/cocina/

From python_capi at behnel.de  Fri Jan  8 19:03:12 2010
From: python_capi at behnel.de (Stefan Behnel)
Date: Fri, 08 Jan 2010 19:03:12 +0100
Subject: [capi-sig] Create instance given its type
In-Reply-To: <445773.22325.qm@web32803.mail.mud.yahoo.com>
References: <445773.22325.qm@web32803.mail.mud.yahoo.com>
Message-ID: <4B477360.3030908@behnel.de>


Gabriel Genellina, 08.01.2010 17:45:
> I want to create an instance given its type object. I expected that
> calling the type would be enough, something like this:
> 
> obj = (MyFooObject *) PyObject_CallFunctionObjArgs(&MyFooType, other, arguments, NULL)
> 
> but it doesn't work (nor even compiles, I think).

You think? Didn't you try it?

You might have to cast the type pointer to PyObject* to make it work.

Stefan

From lanyjie at yahoo.com  Tue Jan 26 12:17:23 2010
From: lanyjie at yahoo.com (Yingjie Lan)
Date: Tue, 26 Jan 2010 03:17:23 -0800 (PST)
Subject: [capi-sig] announcement: expy release 0.5
Message-ID: <290176.43047.qm@web54204.mail.re2.yahoo.com>

Hi all, 

This is to announce expy release 0.5.

expy is an express way to extend Python.

For more information and tutorials on expy, see:

http://expy.sf.net/

Cheers,

Yingjie



      

From philip at semanchuk.com  Sun Jan 31 00:19:31 2010
From: philip at semanchuk.com (Philip Semanchuk)
Date: Sat, 30 Jan 2010 18:19:31 -0500
Subject: [capi-sig] Python 3.x PyObject_HEAD versus PyObject_VAR_HEAD
Message-ID: <7E5ED525-E6CF-4CAA-ADD1-ED5FBDAD6551@semanchuk.com>

Hi all,
I'm trying to port my posix_ipc extension to Python 3, and I'm  
confused by the documentation for PyObject_HEAD and PyObject_VAR_HEAD.

My understanding is that a PyObject-derived type should begin its  
PyTypeObject struct with PyObject_HEAD and a PyVarObject-derived type  
with PyObject_VAR_HEAD. the documentation says of PyVarObject, "This  
type does not often appear in the Python/C API."
http://docs.python.org/3.1/c-api/structures.html#PyVarObject

The doc also says that PyObject_VAR_HEAD, "is used when declaring new  
types which represent objects with a length that varies from instance  
to instance."
http://docs.python.org/3.1/c-api/structures.html#PyObject_VAR_HEAD

I assumed, then, that PyObject_VAR_HEAD would also appear  
infrequently, but that's not the case at all. In fact, I can't find  
PyObject_HEAD used at all in the Python 3.1.1 source code, whereas  
PyObject_VAR_HEAD is used hundreds of times, including for objects  
that don't have a length (like the float type, for instance).

Is the documentation wrong, or am I misreading it? Suggestions  
appreciated.

THanks
Philip