From: Eli Bendersky <eliben@...>
Date: 2006-03-27T02:28:53+09:00
Subject: Re: Verifying keyword arguments


Joel VanderWerf wrote:
> Ross Bamford wrote:
> ..
> > Not sure about libraries (though I'm sure they are out there, check RAA
> > and Rubyforge) but here's a little trick I've used before:
> >
> > args = { :one => 'two', :three => 'four' }
> > # => {:three=>"four", :one=>"two"}
> >
> > h = Hash.new { |h,k| raise ArgumentError, "#{k}" }.merge(args)
> > # => {:three=>"four", :one=>"two"}
> >
> > h[:one]
> > # => "two"
> >
> > h[:three]
> > # => "four"
> >
> > h[:two]
> > ArgumentError: two
> >         from (irb):5
> >         from (irb):11
> >
> > This way, you never actually check the arguments explicitly, but you'll
> > be told if your method uses one that wasn't passed. Obviously for
> > optional arguments you go to the original hash.
> >
>
> What about using rescue for optional arguments? It might be slower though.
> 

What do you mean ? Can you provide an example ?