From: Dmitri Colebatch <dim@...>
Date: 2003-01-22T07:52:16+09:00
Subject: Re: Overloading operators

Thanks Joel et al for all the responses....

   I will use IRB more
   I will use IRB more
   I will use IRB more

:)

cheers
dim


Joel VanderWerf wrote:
> Dmitri Colebatch wrote:
> 
>> I was also wondering if there is a way to implement +=
>>
>>   total = Amount.aud(300)
>>   total += Amount.aud(500)
>>
>>   total -> AUD 800
> 
> 
> No need, since "x += y" is just syntax for "x = x + y". Once you define 
> #+, youve got "+=" as well.
> 
> But this may not be what you want, if your #+ method returns a *new* 
> instance, and you would rather increment the object that total refers to.
> 
> In that case, you may want an #increment method and use it like:
> 
>  total.increment Amount.aud(500)
> 
> Or you could define #<< to do the same thing:
> 
>   total << Amount.aud(500)
> 
> The key point is that these two methods operate destructively on the 
> object referred to by the local variable total, whereas += assigns a new 
> object to that variable.
> 
>