From: Phil Tomson <rubyfan@...>
Date: 2006-07-07T09:39:33+09:00
Subject: Re: quick metaprogramming question: collecting arguments across calls

On 7/6/06, Phil Tomson <rubyfan@gmail.com> wrote:
> On 7/6/06, William Morgan <wmorgan-ruby-talk@masanjin.net> wrote:
> > Hi all,
> >
> > Quick question: is there a better way to write Foo.contains below?
> > Forcing the lexical scoping like this feels wrong.
> >
> > class Foo
> >  def self.contains *o
> >    @contents ||= []
> >    @contents += o
> >    contents = @contents
> >    define_method(:contents) { contents }
> >  end
> > end
> >
> > class Bar < Foo
> >  contains :goat, :boat
> >  contains :stoat
> > end
> >
> > p Bar.new.contents # => [:goat, :boat, :stoat]
> >
>
> How about:
>
>  class Foo
>   class << self
>     def contains *o
>       @contents ||= []
>       @contents += o
>     end
>     attr_accessor :contents
>   end
>   def contents
>     @contents ||= self.class.contents
>   end

Actually, after thinking about it a bit more, I'd probably go with:

     def contents
       self.class.contents
     end

>  end


Phil