From: David Alan Black <dblack@...>
Date: 2002-02-13T23:48:07+09:00
Subject: qualms about respond_to? idiom

Hi --

I'm cool with Ruby's emphasis on object interface rather than type.
The only thing is...  I just can't get myself to be happy about this
idiom:

   if obj.respond_to? "method" then obj.method end

I'm not sure how to express what I don't like about it -- but I guess
the sheer repetitiveness of it, mainly.  It always looks and feels
like a kind of workaround to me, or like something is being done
manually that should somehow just happen.

I actually like the look and feel of this better:

  begin
    obj.method
  rescue NameError
    # stuff
  end

because it doesn't feel like something's being done twice.  But of
course it's slow.  (And I know it's not identical in functionality.)

I don't know... I'm afraid this is more of a notation of a concern
than anything constructive.  Perhaps someone can give me a pep talk on
why I should learn to love that idiom I don't love.


David

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