From: Robert Klemme <shortcutter@...>
Date: 2006-07-07T21:46:00+09:00
Subject: Re: quick metaprogramming question: collecting arguments across calls

2006/7/7, William Morgan <wmorgan-ruby-talk@masanjin.net>:
> 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

Any reason why you cannot simply use a normal attribute accessor?

class Foo
  class <<self
    attr_reader :contents

    def contains *o
      (@contents ||= []).concat o
    end
  end
end

Note, you may want to use a Set to avoid duplicates.

Kind regards

robert

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