Floating point bug?

[Duncan Booth]

Christian Heimes <lists at cheimes.de> wrote:

> Bruno Desthuilliers wrote:
>> I Must have miss something...
> 
> Yeah, You have missed the beginning of the third sentence: "The 
tp_print
> slot is not available from Python code". The tp_print slot is only
> available in C code and is part of the C definition of a type. Hence 
tp_
> as type.

It isn't easy to come up with an example which actually demonstrates 
that print doesn't just call str, but after a little playing around I 
managed it:

>>> class mystr(str):
	def __str__(self):
		return mystr('oops')

	
>>> s = mystr('aargh')
>>> s
'aargh'
>>> str(s)
'oops'
>>> print s

Traceback (most recent call last):
  File "<pyshell#7>", line 1, in <module>
    print s
RuntimeError: maximum recursion depth exceeded
>>> 

Alternatively:

>>> class mystr(str):
	def __str__(self):
		if self=='oops':
		    return 'you printed me!'
		return mystr('oops')

	
>>> s = mystr('aargh')
>>> str(s)
'oops'
>>> str(str(s))
'you printed me!'
>>> print s


and on that last line idle locks until you restart the shell. I can't 
immediately see why; the command line interpreter is fine so it seems 
just to be an idle problem:

>>> class mystr(str):
...     def __str__(self):
...             if self=='oops':
...                 return 'you printed me!'
...             return mystr('oops')
...
>>> s = mystr('aargh')
>>> s
'aargh'
>>> str(s)
'oops'
>>> print s
you printed me!
>>>