From: Robert Klemme <bob.news@...>
Date: 2005-01-25T01:25:52+09:00
Subject: Re: attr


"Trans" <transfire@gmail.com> schrieb im Newsbeitrag
news:1106574588.198173.83840@f14g2000cwb.googlegroups.com...
> In the upcoming release of Ruby Carats I have a little lib called
> attr.rb.
>
> What it does is define a mater #define_attribute which all attribute
> defintions are routed thru. Then I redefine #attr (since current
> definition is basically never used) to call #define_attribute that
> takes multiple args. Here's an example:
>
> .  attr :a, :a=
>
> which is equivalent to:
>
> .  attr_reader :a
> .  attr_writer :a
>
> It also has some extra freatures that are nice like:
>
> .  attr :a?, :b!
>
> which is the same as
>
> .  def a?
> .    @a ? true : @a
> .  end

Why not "def a?() @a end"?

> .  def b!(x)
> .    @b.replace x
> .  end

Hm, I don't like that because it's too special case.  Also you might want
to be able to assign and to replace...

> Also these return an array of the symbols of the methods that get
> defined, so you can use public, private, protected on them. eg.
>
> .  private attr :a
>
> There are a couple of other features too, but I'll leave those aside
> for now, as they are not important to this inquery.
>
> So I have a few questions. First, what do you think of this in general?
> Second, there is no "extra" convenient way to do an accessor b/c I
> haven't been able to find a nice notation --one just has to put both,
> 'attr :a, :a='. Is this too inconvenient? Can anyone think of a good
> notation?

Although I find "attr_accessor" quite lengthy, I don't really see the
benefit of your proposal.  And attr_accessor does indeed define reader and
writer for several attributes...

Kind regards

    robert