From: David Vallner <david@...>
Date: 2006-02-13T07:51:00+09:00
Subject: Re: Struct creates non-standard classes

D�a Nede�a 12 Febru�r 2006 21:48 Robert Klemme nap�sal:
> 2006/2/12, Mark Volkmann <r.mark.volkmann@gmail.com>:
> > On 2/12/06, David Vallner <david@vallner.net> wrote:
> > > D�a Nede�a 12 Febru�r 2006 20:45 Mark Volkmann nap�sal:
> > > > If Struct is a shorthand way for creating Classes, why don't objects
> > > > created from those Classes have instance_variables?
> >
> > My issue is that I wanted to think of Struct as an alternate way of
> > defining a class and that after doing so I could use it like any other
> > class.
>
> You can.
>
> > However, classes created using Struct aren't the same as
> > classes created in the "normal" way and because of that I have to
> > remember when I use them how they differ. I've found one way in which
> > they differ and don't know if there are others.
>
> IMHO you better get used to access instance variables through accessor
> methods instead of directly - even inside another class. You can run
> into numerous problems if you always directly access instance
> variables. The fact that Ruby allows to do this (even from sub class
> methods) does not mean that it's always the best thing to do.
>
> The fact that there are instance variables is a mere detail of the
> implementation. If you stick with this basic OO usage pattern and make
> accessing instance variables directly the exception instead of the
> rule there is no difference in using Struct created classes and
> "normal" classes.
>

Amen.

I blame selfdot syndrome when using setters for people using instance 
attributes directly. I wonder if we're getting that shorthand I saw mentioned 
somewhere, if using accessors wasn't any longer than not using them, I expect 
a dramatic increase of their use internally.

David Vallner