From: Bruce D'Arcus <bdarcus.lists@...>
Date: 2005-06-07T05:40:26+09:00
Subject: Re: newbie read.scan (?) question



Ghislain Mary wrote:

> Because your author and title probably aren't strings as you expect them
> to be but rather arrays.

Ah, right.  Using scan returns an array.  On this ...

> > I have these two classes:
> >
> > class Article
> >
> >   include Journals
> >
> >   attr_reader :title, :author, :description, :url
> >   def initialize(title, author, url)
> >     @title = title
> >     @author = author
> >     @url = url
> >   end
> >
> >   def to_s
> >     "#@title, #@author"
> >   end
> >
> >   def abstract
> >   #
> >   end
> >
> >   def refer
> >     Journals::const_get(:BASE_URL) + "/" +
> >     @url + "&form=refer&file=file.txt"
> >   end
> >
> >   def pdf
> >     Journals::const_get(:BASE_URL) + "/" +
> >     @url + "&form=pdf&file=file.pdf"
> >   end
> > end
> >
> > class Articles
> > #
> >   attr_reader :articles
> >
> >   def initialize
> >     @articles = Array.new
> >   end
> >
> >   def append(article)
> >     @articles.push(article)
> >     self
> >   end
> >
> >   def [](index)
> >     @articles[index]
> >   end
> > end
>
> Why create an Article class and an Articles class?

Because I'm *real* newbie!  My only programming background is with
XSLT.  So I'm trying to also understand basic OO design in this
example.

>  You could make all
> the content of your Articles class also content of the Article class but
> at the class level instead of the instance level. So you just have to
> transform your @articles variable into @@articles and define your append
> and [] methods as self.append and self.[].

Can you give me an abbreviated example of how to do actually do this?
For example, how do I define @@articles under the Article class, and
how would I then define the append method there.

> An other thing: I don't think you need to use
> Journals::const_get(:BASE_URL). You could simply use Journals::BASE_URL.

Ah thanks.  It took me awhile just to get that far!

Bruce