Russ P. a écrit :
(snip)
(answering to Carl Bank) I thought you were saying that encapsulation or so-called
"data
hiding" is worthless.
As far as I'm concerned, I view encapsulation as very desirable, and
data-hidding as totally worthless when applied to Python's object model.
Here's what I think Python should have. I think it should have a
keyword, something like "priv," to identify data or functions as
"private." As I said earlier, "private" for class data or functions
("methods") could be implemented like "protected" in C++. That means
that derived classes would have access to it, but clients of the class
would not. If the client really needs or wants access, he could be
given a sort of "back door" access similar to the current Python rule
regarding double leading underscores. Thus, the client would have
access, but he would know very well that he is using something that
the original designer did not intend for him to use.
It's just a suggestion. I'm not a language expert, and I realize that
I could be missing something important.
Given your very recent discovery of what 'dynamic' *really* means in
Python (like, for exemple, dynamically adding / replacing attributes -
including methods - on a per-class or per-instance basis), possibly, yes.
I also realize, by the way, that Python allows a client of a class to
define a new class member from completely outside the class
definition. Obviously, that cannot be declared private.
Why so ?
But if the
same identifier is already declared private within the class, than the
new definition should not be allowed (because it would defeat the
whole idea of "private" class members).
Why so ?
Metaprogramming (including monkeypatching) is part of the pythoneer's
toolbox, and while it's not something to use without pretty good
reasons, it has many times proven to be a real life saver. In languages
not allowing it, the solutions to the class of problems easily solved by
monkeypatching happens to be at best a kludge, at worst plain
unsolvable, at least without too much effort to be even worth it. Your
above proposition would arbitrarily make possible and useful things
either uselessly complicated or near impossible.
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