From: Robert Klemme <shortcutter@...>
Date: 2007-09-04T19:58:03+09:00
Subject: Re: Struct is cleverer than the documentation claims

2007/9/4, Paul Butcher <paul@82ask.com>:
> The Pickaxe book asserts that it will be possible to pass a block to
> Struct.new in Ruby 1.9. While spelunking the code, I discovered that the
> functionality has actually been present since 1.8.3. I've blogged about
> this here:
>
> http://www.texperts.com/2007/09/03/hidden-feature-in-rubys-struct/
>
> But reading this mailing list, I notice that there's another way to
> achieve a similar effect, specifically deriving from Struct.new.
>
> So, both of the following achieve broadly the same effect:
>
> > Customer = Struct.new(:name, :address) do
> >   def to_s
> >     "Customer called '#{name}' living at '#{address}'"
> >   end
> > end
>
> > class Customer < Struct.new(:name, :address)
> >   def to_s
> >     "Customer called '#{name}' living at '#{address}'"
> >   end
> > end
>
> Which leads to the question, what *are* the differences, and should I
> prefer one approach over the other?

Well, difference is that you get two classes vs. one class.  I
frequently use the first idiom because I do not see the point in
creating two classes for this scenario.  IMHO a base class makes sense
only if you want to inherit multiple times or separate concerns.
Neither is the case here.

Kind regards

robert