From: Yohanes Santoso <ysantoso@...>
Date: 2002-11-16T07:26:02+09:00
Subject: Re: Newbie questions regarding getter/setter methods...

christopher.j.meisenzahl@citicorp.com writes:

> class Song  
>   attr_reader :name, :artist, :duration  
> end  

expands to:

> class Song  
>   def name  
>       @name  
>   end  
>   def artist  
>        @artist  
>   end  
>   def duration  
>        @duration  
>   end  
> end  

> Do I also have to declare @name, @artist, and @duration within the
> method? Or are they implicitly declared by declaring the accessor
> methods?

You don't have to. Ruby use a first-use policy for variables. Meaning
it's declared and defined when Ruby first encounter the variable. Or
if you like you can do: attr :name, :artist, :duration which will
simply declare them (mostly for documentation purposes).

> In general, how do member variables work? Are they all private and
> require accessor/reader methods to be accessed at all? My background
> includes a little bit of C/C++ and Java.

They are all private to outsider (not subclasses). To make them
public, you have to either attr_reader or attr_writer or attr_accessor
them.

Expriment with irb. It's the handiest tool to explore ruby.

YS.