[Python-Dev] unicode and __str__

[Neil Schemenauer]

On Mon, Aug 30, 2004 at 11:35:17PM +0200, "Martin v. L?wis" wrote:
> Neil Schemenauer wrote:
> >But unicode() will also return __str__, eg.
> >
> >    >>> class A:
> >    ...   def __str__(self): 
> >    ...     return u'\u1234'
> >    ... 
> >    >>> unicode(A())
> >    u'\u1234'
> >
> >Why would I want to use __unicode__?  
> 
> This class is incorrect: it does not support str().

Forgive me if I'm being obtuse, but I'm trying to understand the
overall Python unicode design.  This works:

    >>> sys.getdefaultencoding()
    'utf-8'
    >>> str(A())
    '\xe1\x88\xb4'

Can you be more specific about what is incorrect with the above
class?

> >Shouldn't we be heading to a
> >world where __str__ always returns unicode objects?
> 
> No. In some cases, str() needs to compromise, where unicode()
> doesn't.

Sorry, I don't understand that statement.  Are you saying that we
will eventually get rid of __str__ and only have __unicode__?

[on having __str__ assume some character encoding]
> Perhaps. What are you proposing to do about this? Ban, from the face
> of the earth, what seems like a horrible design to you?

If only we could. :-)  Seriously though, I'm trying to understand
the point of __unicode__.  To me it seems to make the transition to
unicode string needlessly more complicated.

  Neil