From: dblack@...
Date: 2003-01-17T10:35:32+09:00
Subject: Re: quick: it responds, it evaluates, and is not empty

Hi --

On Fri, 17 Jan 2003, Tom Sawyer wrote:

> quick quest: anyone know of a nice slick short and sweet way to do this:
>
> 	if self.respond_to?(:ameth)
> 		if ameth
> 			if not ameth.to_s.empty?
> 				...
> 			end
> 		end
> 	end

I think it's probably worth having a temp variable here to avoid
calling the method an extra time:

  if respond_to?(:ameth)
    if (a = self.ameth)
      unless a.to_s.empty?
        ...
      end
    end
  end

or Boolean operator-wise (see other reply):

  if respond_to?(:ameth) && (a = self.ameth) &&! (a.to_s.empty?)
     ...
  end

or some combination.

I continue to dislike the repetition of the

  if obj.respond_to?(:meth) then obj.meth ...

thing, although I don't know how to circumvent it efficiently and
effectively.


David

-- 
David Alan Black
home: dblack@candle.superlink.net
work: blackdav@shu.edu
Web:  http://pirate.shu.edu/~blackdav