# File lib/rational.rb, line 305
  def <=> (other)
    if other.kind_of?(Rational)
      num = @numerator * other.denominator
      num_a = other.numerator * @denominator
      v = num - num_a
      if v > 0
        return 1
      elsif v < 0
        return  -1
      else
        return 0
      end
    elsif other.kind_of?(Integer)
      return self <=> Rational.new!(other, 1)
    elsif other.kind_of?(Float)
      return Float(self) <=> other
    elsif defined? other.coerce
      x, y = other.coerce(self)
      return x <=> y
    else
      return nil
    end
  end