From: dblack@...
Date: 2006-08-07T04:01:51+09:00
Subject: Re: Singleton methods with method_missing

Hi --

On Mon, 7 Aug 2006, Pat Maddox wrote:

> I don't have any practical use for this, but I was experimenting a bit.
> I just want to create singleton methods on objects of this class.
> There's more to come, but this is the part I'm stuck at :)
>
> This code doesn't actually work, but I think it's close (I hope?)
>
> class OneShot
>  def method_missing(m)
>    class << self
>      define_method(m) { puts m.to_s }
>    end
>    send(m)
>  end
> end
>
> When I do this I get "NameError: undefined local variable or method `m'
> for #<Class:#<OneShot:0x32cf74>>" so I think it means that m just isn't
> in scope for the singleton class.  How can I define the singleton
> method?  Is there any way to use binding here?

Try this:

   module Kernel
     def singleton_class        # RCR 231
       class << self; self; end
     end
   end

   class OneShot
     def method_missing(m)
       singleton_class.class_eval do
         define_method(m) { puts m }
       end
     end
   end

   o = OneShot.new
   o.x      # method 'x' is created
   o.x      # 'x' is printed


David

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