From: Jeff Putsch <putsch@...>
Date: 2001-06-27T07:05:42+09:00
Subject: [ruby-talk:16936] Re: [Newbie] overload + operator for instance variable

Thanks,

Your suggestion works like a charm.

Jeff.

On Wed, Jun 27, 2001 at 06:02:54AM +0900, Avi Bryant wrote:
> On Wed, 27 Jun 2001, Jeff Putsch wrote:
> 
> >      def desc=(newDesc)
> >        @desc = strToArray(newDesc)
> >      end
> >      def desc
> >        @desc.join(', ')
> >      end
> 
> >    c = Category.new
> >    c.desc = "a,b,c"    # --> c's @desc = ["a", "b", "c"]
> >    c.desc += "d,f,g"   # --> c's @desc = ["a", "b", "cd", "f", "g"]
> > 
> > As you can see, I'm attempting to store the desc as an array, yet pass
> > in comma-delimited strings. 
> 
> Well, I'm not sure I would personally use operator overloading for this,
> but if you really want it, you could maybe change your accessor to
> 
> def desc
>   descString = @desc.join(',')
>   def descString.+(str)
> 	"#{self}, #{str}"
>   end
>   descString
> end
> 
> Note that it doesn't make sense to override an operator for a particular
> instance variable - a variable is just a slot, it has no type, and no
> methods.  What I'm doing here is overriding an operator for a particular
> object - in this case, the string being returned from desc.
> 
> Avi
>