Python Gotcha's?

[Steven D'Aprano]

On Sun, 15 Apr 2012 02:23:27 -0700, Bryan wrote:

> Steven D'Aprano wrote:
>> Bryan wrote:
>> > Python 3(K) likes to use the same '.py' file extension as its
>> > incompatible predecessors,
>>
>> And so it should.
> 
> We disagree. Not surprising in a "gotcha's" thread.

Yes, but I have reasons for disagreeing, which you trimmed out of your 
response. If you have reasons for thinking that a separate file extension 
for Python 3 is a good idea, you are keeping it to yourself.

Python and C are different languages. Python 2 and Python 3 are not, they 
are the same language with only a few minor dialect differences.

There is a practical argument against separate file extensions: which 
extension do you use for code intended to run with both Python 2 and 3?

We didn't need a new file extension for the transition between Python 2.5 
(string exceptions are legal) and Python 2.6 (string exceptions cause a 
SyntaxError exception). Nor did we need a new file extension for the 
transition between Python 2.1 (nested functions behaved one way) and 
Python 2.2 (nested functions behaved a different way). We certainly 
didn't have a new file extension when the bastion or gopher modules were 
removed from the standard library, backwards-incompatible changes if I've 
ever seen one.

If there's a good argument in favour of separate file extensions for 
Python 2 and Python 3 (one which doesn't also apply to, say, Python 2.5 
and 2.6, or 3.1 and 3.2) I'm afraid I don't know it.


-- 
Steven