From: "Mauricio Fernández" <batsman.geo@...>
Date: 2002-10-23T21:09:02+09:00
Subject: Re: Things That Newcomers to Ruby Should Know (10/16/02)

On Wed, Oct 23, 2002 at 06:28:29PM +0900, Bulat Ziganshin wrote:
> Hello Ian,
> 
> Tuesday, October 22, 2002, 7:30:19 AM, you wrote:
> 
> IM> I understand that, but since 'a' already exists prior to assigning a + b
> IM> to it, why does it need to be recreated? Where strings are concerned,
> IM> I don't see why this would be any different to 'a << b'.
> 
> main problem is that object pointed by 'a' mauy be also pointed by
> another variable an if you change this object directly your code wil
> have SIDE EFFECT. are you really need this? :) so '<<' and other
> methods changing object itself must be used very carefully, preferably
> for local variables and other "own" objects
> 
> example of this side effect:
> 
> def a(s)
>   s << '!'
>   s += '?'
>   return s
> end
> 
> x='1'
> y=a(x)
> p x,y

Would it be possible for Ruby to know whether an object is referenced by
several variables so += does '<<' or '... = ... + ...' when appropriate?

Perhaps a bit in each String indicating whether it is shared or
not would make it... and GC issues could be ignored at first.

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