From: "Bartosz Dziewoński" <matma.rex@...>
Date: 2011-10-14T22:29:15+09:00
Subject: Re: What’s the best way of checking if an argument has been given or not?

You can use this syntax, too. "args" becomes an array of all arguments given.

  def foo *args
    if args.length==0
      puts 'no argument was given'
    else
      puts args[0]
    end
  end

If you only allow one argument, you should do some checking whether
there are too many.

-- Matma Rex