[Python-ideas] PEP-3151 pattern-matching

[Georg Brandl]

On 12.05.2011 21:06, M.-A. Lemburg wrote:
> Antoine Pitrou wrote:
>> On Fri, 08 Apr 2011 10:59:16 +0200
>> "M.-A. Lemburg" <mal at egenix.com> wrote:
>>>>
>>>> I think EnvironmentError, WindowsError, VMSError, OSError, mmap.error
>>>> and select.error should definitely all be merged with IOError, as they
>>>> aren't used consistently enough to make handling them differently
>>>> reliable even in current code.
>>>
>>> Their use may be inconsistent in a few places, but those cases
>>> are still well-defined by the implementation, so code relying
>>> on that well-defined behavior will break in subtle ways.
>> 
>> Another quirk occurred to me today: select.error doesn't derive from
>> EnvironmentError, and so it doesn't have the errno attribute (even
>> though the select module "correctly" instantiates it with a (errno,
>> message) tuple). Also, its str() is borked:
>> 
>>>>> e = select.error(4, "interrupted")
>>>>> str(e)
>> "(4, 'interrupted')"
>>>>> raise e
>> Traceback (most recent call last):
>>   File "<stdin>", line 1, in <module>
>> select.error: (4, 'interrupted')
> 
> Works fine in Python 2.7:
> 
>>>> import select
>>>> e = select.error(4, "intr")
>>>> e
> error(4, 'intr')

Note that this is the repr(), while Antoine showed the str().

But the str() looks correct to me as well (for an exception that doesn't
derive from EnvironmentError).

Georg