From: Robert Klemme <bob.news@...>
Date: 2003-06-26T00:44:46+09:00
Subject: Re: protect parents from children


"Simon Strandgaard" <0bz63fz3m1qt3001@sneakemail.com> schrieb im
Newsbeitrag news:pan.2003.06.25.11.28.38.783568@sneakemail.com...
> On Wed, 25 Jun 2003 21:02:10 +0900, ts wrote:
>
> >>>>>> "S" == Simon Strandgaard <0bz63fz3m1qt3001@sneakemail.com>
writes:
> >
> > S> Me don't understand.   If I add debug-print's to selftest then I
see that
> > S> the parent *has* changed  ??   Can you enligthen me ?
> [snip]
> >
> >  I don't see a parent nor a child : I just see an object which modify
one
> >  of these instance variable.
>
> OK. I think im to c++bias'ed (assuming too much).

No, it's just an OO thingy.  Even in C++ there is no parent or child: just
a single instance with several instance variables.  The only difference
between C++ and Ruby with respect to this issue are the scoping and
visibility rules.  But the basic principle is the same.

> Is it possible to make the variable readonly to the child ?

Not without complicated tricks. Typically you want to avoid outside access
to instance variables but not access through child class methods.

    robert