[Python-Dev] Revised PEP 349: Allow str() to return unicode strings

Thu Aug 25 19:03:32 CEST 2005

On Wed, Aug 24, 2005 at 09:11:18PM +0200, Dieter Maurer wrote:
> Neil Schemenauer <nas at arctrix.com> writes on 2005年8月22日 15:31:42 -0600:
> > The code was fixed by changing
> > the line "header = str(header)" to:
> > 
> > if isinstance(header, unicode):
> > header = header.encode('ascii')
>> Note, that this is not equivalent to the old "str(header)":
>> "str(header)" used Python's "default encoding" while the
> new code uses 'ascii'.

It also doesn't call __str__ if the object is not a basestring
instance. I have a hard time understanding the exact purpose of
calling str() here. Maybe Barry can comment.
> Can we get a new builtin with the exact same behaviour as
> the current "str" which can be used when we do require an "str"
> (and cannot use a "unicode").

That fact that no code in the standard library requires such a
function (AFAIK), leads me to believe that it would not be useful
enough to be made a built-in. You would just write it yourself:
 def mystr(s):
 s = str(s)
 if isinstance(s, unicode):
 s = s.encode(sys.getdefaultencoding())
 return s
Cheers,
 Neil