Will python never intend to support private, protected and public? - comp.lang.python

Message from discussion Will python never intend to support private, protected and public?

Fredrik Lundh

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More options 28 Sep 2005, 16:45

Newsgroups: comp.lang.python

From: "Fredrik Lundh" <fred...@pythonware.com>

Date: Wed, 28 Sep 2005 17:45:37 +0200

Local: Wed 28 Sep 2005 16:45

Subject: Re: Will python never intend to support private, protected and public?

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Tony Meyer wrote:
>> I thought about it, but I didn't mention it in the end because this
>> feature ("name mangling") isn't intended as a mechanism for making
>> things private - it's intended to prevent namespace clashes when doing
>> multiple inheritance.

> That's not what the documentation says:

> """
> 9.6 Private Variables

> There is limited support for class-private identifiers.
> [...]
> Name mangling is intended to give classes an easy way to define
> ``private'' instance variables and methods,
> [...]
> """

> <http://docs.python.org/tut/node11.html>

the sentence you're quoting the first part of continues:

without having to worry about instance variables defined by derived
classes

and the paragraph later says:

Note that the mangling rules are designed mostly to avoid accidents

and both sentences are from the *tutorial*, which doesn't exactly
qualify as a design document. if you want more rationale, here's the
post that led to the current design:

http://groups.google.com/group/comp.lang.python/msg/e79f875059d9a2ba

"In my version, private data has it's own scope, so that name clashes
will not occur if a private with the same name is used in a subclass."

see the rest of that thread for more about the history of __.

</F>

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