From: Austin Ziegler <austin@...>
Date: 2002-11-26T13:37:29+09:00
Subject: Re: Things That Newcomers to Ruby Should Know (11/24/02)

On Tue, 26 Nov 2002 13:15:31 +0900, Jason Persampieri wrote:
>> You're not changing the letter 'a' itself; you're changing a
>> string which has the letter 'a' in it.
>> 
>> To put it another way:
>> 
>> You can have more than one "a" string:
>>  s = "a"
>>  t = "a"
>> and if you change or increment s:
>>  s.succ!  # s is now "b"
>> t doesn't change.
>> 
>> But there's only one of each number. If you were allowed to do
>>  3.succ!
>> or
>>  3 += 1
>> then when you did this:
>>  puts 3 * 5
>> the output would be "20", because you would have incremented the
>> actual object 3.
> So wouldn't it make send to have a somewhat global ..succ! method
> and only allow the programmer to increment (++) on those that have
> it?
> 
> I mean, C doesn't allow 3++ either (well, it may ALLOW it, but it
> doesn't mean anything). I think that argument is pretty bogus.

The difference is that 3 is an immediate value object. There is only
ever one object with the value 3.

When I do:
  a = 3
I am *aliasing* (referencing) 3; I am not setting an object to have
the immediate value 3.

Thus, if I were to do a.succ!, it would be no different than if I
were doing 3.succ!, because of the immediacy of Fixnum values and
the fact that variables are ONLY references to objects, and not
objects themselves.

(To be honest, I haven't missed ++ because I've been working in
PL/SQL and Pascal recently.)

-austin
-- Austin Ziegler, austin@halostatue.ca on 2002.11.25 at 23.33.34