On 02/15/2011 11:03 PM, Phil Christensen wrote:

On Feb 15, 2011, at 5:36 AM, Attila Nagy wrote:

...

Hi,

I'm trying to do an LMTP implementation based on smtp.py and came to the issue of class private variables with double underscores. Examples: http://twistedmatrix.com/trac/browser/trunk/twisted/mail/smtp.py#L746 http://twistedmatrix.com/trac/browser/trunk/twisted/mail/smtp.py#L815 and a lot of occurrences in this file.

This makes me a problem, because I override some functions in a class, named LMTP, so these cannot work together.

What's the rationale of using these, instead of static names? I've got no idea of the rationale for using double-underscore notation, but why does that prevent you from subclassing it? Just add the class name to it for access:

class A: def __init__(self): self.__test = 'test'

a = A()

print a._A__test

I can make it work, but I have to hardcode variable names like the above and I don't understand why is this needed. It's so ugly. BTW, this is the situation: class SMTP: def something(self): self.__inheader = True class LMTP(SMTP) def other(self): if self.__inheader == True: and I get other from SMTP, and make some little tweaks. This way, I have to rename all variables in LMTP's functions from __stuff to _SMTP_stuff.

Hi, I know what it does, I just don't get why it was used in smtp.py. But you are right, I should have mentioned that in the subject (adding ... in smtp.py). On 02/15/2011 11:33 PM, Jason Rennie wrote:

In case you haven't seen it, here's what the python tutorial says about double-underscore:

http://docs.python.org/tutorial/classes.html#private-variables

Jason

On Tue, Feb 15, 2011 at 5:36 AM, Attila Nagy mailto:bra@fsn.hu> wrote:

Hi,

I'm trying to do an LMTP implementation based on smtp.py and came to the issue of class private variables with double underscores. Examples: http://twistedmatrix.com/trac/browser/trunk/twisted/mail/smtp.py#L746 http://twistedmatrix.com/trac/browser/trunk/twisted/mail/smtp.py#L815 and a lot of occurrences in this file.

This makes me a problem, because I override some functions in a class, named LMTP, so these cannot work together.

What's the rationale of using these, instead of static names?

Thanks,

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