From: Rick DeNatale <rick.denatale@...>
Date: 2008-02-16T02:01:02+09:00
Subject: Re: @var = change to accessor method? Why?

On Wed, Feb 13, 2008 at 1:09 PM, Philipp Hofmann <phil@s126.de> wrote:
>
>  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.

This is one of those topics which got me writing again:

http://talklikeaduck.denhaven2.com/articles/2008/02/15/best-practice-patterns-accessors-and-encapsulation


-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/