From: Rob Biedenharn <Rob@...>
Date: 2007-11-08T02:52:11+09:00
Subject: Re: Is there a "||" that treats "" also as false?

On Nov 7, 2007, at 12:36 PM, Joshua Muheim wrote:

> I finally came up with this:
>
> class String
>  def |(alternative)
>    (self.nil? or self == "") ? alternative : self
>  end
> end
>
> class NilClass
>  def |(alternative)
>    alternative
>  end
> end
>
> Is this OK? Or do I accidently override some existing method? Because
> without the definition above
>
> nil | "asdf"
>
> returns
>
> true!


That's because NilClass#| is already defined so you probably should  
leave it alone.

For the String part, you'll only ever get truth from self.nil? if self  
really is nil so that method would be better refactored as:

class String
   def |(alternative)
     empty? ? alternative : self
   end
end

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com