Stefan Behnel wrote: > Neal Becker, 27.08.2010 13:32: >> I've noticed that cython extension classes are more restrictive than >> boost::python classes. In particular, I believe boost::python allows >> attributes to be added by python code to boost::python classes, while >> cython >> classes are 'closed'. Is this correct? > > I don't know what kind of classes boost uses, but the above only applies > to extension types in Cython. Normal Python classes behave as in normal > Python. And it should be possible to add a __dict__ to extension types > without much hassle, it's just that most people don't want that. > Initialising a dict takes time during type instantiation and takes > additional space during the lifetime of the object. > > BTW, now that you mention it - does anyone know what became of the idea to > allow a > > cdef __dict__ > > attribute notation (as for __weakref__) to add a dict to an extension > type? AFAIR, that was already proposed more than once on this list. > > Stefan
I just tested it. With boost::python you can add attribute to class as well as instance of class. Example: accumulator is a boost::python extension module of mine import pyublas import numpy as np from accumulator import * s = stat2nd_double dir(s) Out[20]: ['Mean', 'RMS', 'Var', '__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__iadd__', '__init__', '__instance_size__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'mean', 'rms', 'var'] s.stuff = 'hi' dir(s) Out[4]: ['Mean', 'RMS', 'Var', '__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__iadd__', '__init__', '__instance_size__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'count', 'mean', 'rms', 'stuff', 'var'] x = s() In [6]: dir(x) Out[6]: ['Mean', 'RMS', 'Var', '__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__iadd__', '__init__', '__instance_size__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'count', 'mean', 'rms', 'stuff', 'var'] In [7]: x.stuff Out[7]: 'hi' In [8]: x.junk='bye' In [9]: dir(x) Out[9]: ['Mean', 'RMS', 'Var', '__call__', '__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__iadd__', '__init__', '__instance_size__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'count', 'junk', 'mean', 'rms', 'stuff', 'var'] In [10]: _______________________________________________ Cython-dev mailing list Cython-dev@codespeak.net http://codespeak.net/mailman/listinfo/cython-dev
