Why less emphasis on private data?

[Thomas Ploch]

sturlamolden schrieb:
> time.swift at gmail.com wrote:
>> Coming from a C++ / C# background, the lack of emphasis on private data
>> seems weird to me. I've often found wrapping private data useful to
>> prevent bugs and enforce error checking..
>>
>> It appears to me (perhaps wrongly) that Python prefers to leave class
>> data public.  What is the logic behind that choice?
> 
> The designers of Java, C++, C#, Ada95, Delphi, etc. seem to think that
> if an object's 'internal' variables or states cannot be kept private,
> programmers get an irresistible temptation to mess with them in
> malicious ways. But if you are that stupid, should you be programming
> in any language? The most widely used language is still C, and there is
> no concept of private data in C either, nor is it needed.

There is a kind of this concept in C with 'static' declarations.

> As mentioned in other replies, it is not rocket science to access a
> class private data. In C++ you can cast to void*, in Java and C# you
> can use reflection. C++ is said to be an "unsafe" language because
> programmers can, using a few tricks, mess with the vtables. But how
> many really do that?

Exactly, if they were available, a lot more would do that. I think this
is the point. Programmers who can do that normally are sensible towards
that people who have designed this or that knew what they were doing.
But there are enough people that don't have a clue and _will_ fiddle
around and then flame all kind of mailing lists with requests for help
cause they did it wrong.