[Python-Dev] str vs. unicode (original) (raw)

Nick Coghlan ncoghlan at iinet.net.au
Wed Jan 19 13:26:14 CET 2005

M.-A. Lemburg wrote:

So if we fix str this would be a bugfix for 2.4.1. If we fix the rest, this would be a new feature for 2.5.

I have a feeling that we're better off with the bug fix than the new feature. str and unicode as well as the other hooks were specifically added for the type constructors to use. However, these were added at a time where sub-classing of types was not possible, so it's time now to reconsider whether this functionality should be extended to sub-classes as well.

It seems oddly inconsistent though:

"""Define str to determine what your class returns for str(x).

NOTE: This won't work if your class directly or indirectly inherits from str. If that is the case, you cannot alter the results of str(x)."""

At present, most of the type constructors need the caveat, whereas str actually agrees with the simple explanation in the first line.

Going back to PyUnicode, PyObject_Unicode's handling of subclasses of builtins is decidedly odd:

Py> class C(str): ... def str(self): return "I am a string!" ... def unicode(self): return "I am not unicode!" ... Py> c = C() Py> str(c) 'I am a string!' Py> unicode(c) u''

Cheers, Nick.

-- Nick Coghlan | ncoghlan at email.com | Brisbane, Australia

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