From: Philipp Hofmann <phil@...126.de>
Date: 2008-02-14T03:09:45+09:00
Subject: Re: @var = change to accessor method? Why?


On Wed, Feb 13, 2008 at 05:51:33PM +0900, Ryan Davis wrote:
>
>> ...
>
> I'm afraid you're confusing encapsulation with information hiding [0],  

i don't think so, but thank for pointing me to that article. without
reading it, i would have thought: hm, presumably he is right, i'm
confusing something. ;)

> ...
>
> Providing accessor methods is the only sane way to make your code and  
> its subclasses more resilient to change. It allows you to change the  
> internals without affecting the subclasses that use that interface.  
> Classes that use ivars directly are more brittle and require more work  
> to maintain.

that is in fact a good point. i wasn't aware of that. and might make me
change my mind. could you or anyone else point out a problamtic case
in few lines of code? just curious.

>> ...
>
> [0] http://c2.com/cgi/wiki?EncapsulationIsNotInformationHiding
> [1] As I've said before, if it is anywhere in ruby and evaled or parsed 
> in any way, I can get my hands on it and manipulate it. If that scares or 
> bothers you, you're using the wrong language.

I totally agree. But it still makes a difference for what reasons
e.g. 'send' is used. It's on thing to use it for some nifty
metaprogramming but it's another to exploit it to access an otherwise
(maybe for a good reason) unaccessible object.

g phil