> From: Bret Jolly (oinkoink+unet / rexx.com)
> Subject: Broken lcm 
> 2004-05-20 11:05:01 PST
> Ruby version: ruby 1.9.0 (2004-05-10) [i686-linux]
> The lcm method used by mathn (and defined in rational.rb)
> is broken.
...
> irb(main):003:0> 0.lcm(0)
> ZeroDivisionError: divided by 0
...
> But the lcm of 0 and 0 is well-defined (and equal to 0).
> 
> Regards, Bret

The following corrects Integer#lcm in rational.rb (with one less call to #abs, too).

  def lcm(other)
    if self.zero? or other.zero?
      0
    else
      (self.div(self.gcd(other)) * other).abs
    end
  end