Operator overloading demo in Ruby

# Just for demo.  DON'T DO THIS IN PRODUCTION CODE.

class MyComplex
  def initialize(real=0, imag=0)
    @real = real
    @imag = imag
  end

  def +(other)
    class_name = self.class
    result = class_name.new
    case other
    when result.class
      result.real = self.real + other.real
      result.imag = self.imag + other.imag
    else
      result.real = self.real + other
      result.imag = self.imag
    end
    result
  end

  def real
    return @real
  end

  def real=(num)
    @real = num
  end

  def imag
    return @imag
  end

  def imag=(num)
    @imag = num
  end

  def to_s
    real_str = @real.to_s
    imag_str = @imag >= 0 ? '+' + @imag.to_s : @imag.to_s
    real_str + imag_str + 'i'
  end
end

[Fixnum, Bignum, Float].each do |klass|
  eval <<-END
class #{klass}
    alias_method :plus, :+
    def +(other)
      if other.is_a? MyComplex
        class_name = other.class
        result = class_name.new
        result.real = self.plus(other.real)
        result.imag = other.imag
        return result
      else
        self.plus(other)
      end
    end
  end
END
end

if __FILE__ == $0
  a = MyComplex.new 3, 4
  b = MyComplex.new 4, 3
  puts a + b
  puts a + 2
  puts 2 + a
  puts 3.2 + a
  puts (2**100) + a
end