From: "Darryl L. Pierce" <mcpierce@...>
Date: 2011-10-04T23:53:09+09:00
Subject: Re: Operator Overloading

On 10/04/2011 10:03 AM, Brian Candler wrote:
> Darryl Pierce wrote in post #1024950:
>> Define a + method on your Point class:
>>
>> def +(other)
>>   self.x += other.x
>>   self.y += other.y
>>   self.z += other.z
>>   self
>> end
> 
> Warning!! That will *mutate* the point passed as the left-hand argument 
> of the '+'!
> 
> I would suggest instead:
> 
> def +(other)
>   Point.new(x+other.x, y+other.y, z+other.z)
> end

DOH! Good point!

> (Of course, 'x' and 'self.x' are the same; you can write 'self.x' if you 
> think it's clearer)

I don't think so. 'x' is a local variable, while '@x' is an instance
variable. And since the fields are instance variables they have to be
prefixed with '@'.

-- 
Darryl L. Pierce <mcpierce@gmail.com>
http://mcpierce.multiply.com/
"What do you care what people think, Mr. Feynman?"