Nick Coghlan wrote:
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:
Those APIs were all written long before there were sub-classes
of types.
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''
Ah, looks as if the function needs a general overhaul :-)
This section should be do a PyString_CheckExact():
if (PyString_Check(v)) {
Py_INCREF(v);
res = v;
}
But before we start hacking the function, we need a general
picture of what we think is right.
Note, BTW, that there is also a tp_str slot that serves
as hook. The overall solution to this apparent mess should
be consistent for all hooks (__str__, tp_str, __unicode__
and a future tp_unicode).
--
Marc-Andre Lemburg
eGenix.com
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