From: "Darryl L. Pierce" <mcpierce@...>
Date: 2011-10-04T22:15:57+09:00
Subject: Re: Operator Overloading

On 10/04/2011 01:11 AM, Thescholar Thescholar wrote:
> Let's suppose I have a class like this one and then I create two
> objects:
> 
> =-=-=-=-=-=-=-=-=-=-=-=
> class Point
> 
>   def initialize
>     x = 5
>     y = 10
>     z = 25
>   end

This won't work since x, y and z in the above are local to the
constructor. So those variables will be lost when the constructor exits.

> 
> end
> 
> a = Point.new
> b = Point.new
> =-=-=-=-=-=-=-=-=-=-=-=
> 
> How do I do if I want to add a and b together to a new point called c?
> Example:
> 
> c = a + b
> 
> How exactly should I implement the operator overloading feature? So that
> x = 10, y = 20, z = 50. There are hardly any tutorial for this...

Define a + method on your Point class:

def +(other)
  self.x += other.x
  self.y += other.y
  self.z += other.z
  self
end

That last line is IMPORTANT. Remember, Ruby methods treat the last value
evaluated in a method as the return value. So if you don't put self in
then the return value for the + method will be the last addition.

So now with the above:

c = a + b

is the equivalent of doing:

c = a.+(b)

HTH.

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