Guido van Rossum wrote:
> I think it's fine to wait for 3.2. Maybe add something to the docs
> about not subclassing unicode in C.

We should have a wider discussion about this on python-dev.

I'll publish the unicoderef extension and then we can see
whether users want this or not.

Antoine's patch makes such extensions impossible (provided you
don't want to copy over the complete unicodeobject.c
implementation in order to change the memory allocation
scheme).

Note that in Python 2.x you don't have such issues because
there, most tools for text processing will happily work on
any sort of buffer, so you don't need a string sub-type
in order to implement e.g. references into another string
(the buffer type will allow you to do this easily).