From: Brian Candler <b.candler@...>
Date: 2010-02-15T18:41:11+09:00
Subject: Re: 'def', but with a closure

Robert Klemme wrote:
> You can at least shorten it a bit
> 
>  @cars.each do |owner, model|
>    widget = TkLabel.new(:text => model)
>    (class << widget; self; end).send(:define_method, :get_owner) do
>      owner
>    end
>  end

You can use a block (non-string) eval, which isn't quite as short but 
avoids the 'send'. It's nicer if you have a whole bunch of define_method 
calls.

  @cars.each do |owner, model|
    widget = TkLabel.new(:text => model)
    (class << widget; self; end).class_eval do
      define_method(:get_owner) do
        owner
      end
    end
  end

Or use an explicit instance variable instead of a closure.

  module Owner
    def get_owner
      @owner
    end
  end

  @cars = {"jim"=>"KA", "fred"=>"Porsche", "trunky"=>"Mini"}
  @cars.each do |owner, model|
    widget = TkLabel.new(:text => model)
    widget.extend Owner
    widget.instance_variable_set(:@owner, owner)
    # or: widget.instance_eval { @owner = owner }
    # or: widget.set_owner(owner)
  end
-- 
Posted via http://www.ruby-forum.com/.