15 August 2012

Kay Hayen
Python

Python 3 wonders - Breaking str

That just killed some hope inside of me, breaking code that uses str ought to be forbidden.

Update

Turns out, this only a bug, and not intentional. And the bug is only in the doc string, so it’s being fixed, and there is no inconsistency then any more.

Python 3:

Python 3.2.3 (default, Jun 25 2012, 23:10:56)
[GCC 4.7.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> print( str.__doc__ )
str(string[, encoding[, errors]]) -> str

Create a new string object from the given encoded string.
encoding defaults to the current default string encoding.
errors can be 'strict', 'replace' or 'ignore' and defaults to 'strict'.
>>> str( string = "a" )
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: 'string' is an invalid keyword argument for this function

Python 2:

Python 2.7.3 (default, Jul 13 2012, 17:48:29)
[GCC 4.7.1] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> print str.__doc__
str(object) -> string

Return a nice string representation of the object.
If the argument is a string, the return value is the same object.
>>> str( object = "a" )
'a'

I do understand that it’s in fact just the old unicode built-in. In fact, I made it work like that for Nuitka just now. But there is a difference, for Python2, it was well behaved.

Python 2:

>>> print unicode.__doc__
unicode(string [, encoding[, errors]]) -> object

Create a new Unicode object from the given encoded string.
encoding defaults to the current default string encoding.
errors can be 'strict', 'replace' or 'ignore' and defaults to 'strict'.
>>> unicode( string = "a" )
u'a'

Is Python3 supposed to be more clean or what? I think it is not happening.

Yours,

Kay Hayen

Python 3 wonders - Barry BDFL   Nuitka Release 0.3.24