From: Ken Bloom <kbloom@...>
Date: 2007-09-03T01:10:10+09:00
Subject: Re: attr_reader

On Sun, 02 Sep 2007 08:53:59 +0900, 7stud *** wrote:

> And this confirms it:
> 
> class Song
>      #attr_reader :name, :artist, :duration
> end
> 
> song = Song.new
> 
> puts song.name
> puts song.artist
> puts song.duration
> 
> puts song.fake
> 
> --output:---
> r1test.rb:8: undefined method `name' for #<Song:0x25648> (NoMethodError)

There are two different things going on with attribute readers:

attr_reader :foo creates a *method* to access the instance variable @foo. 
When you get a NoMethodError, because there's no such method.

Supposing you create an instance variable @bar in some method, such as 
initailze, but have no attr_reader for it. You'll still get a 
NoMethodError because attr_reader wasn't called to create a method for it.

--Ken

-- 
Ken Bloom. PhD candidate. Linguistic Cognition Laboratory.
Department of Computer Science. Illinois Institute of Technology.
http://www.iit.edu/~kbloom1/