From: Lyle Johnson <ljohnson@...>
Date: 2001-09-26T07:21:17+09:00
Subject: [ruby-talk:21689] Re: manipulating "immutable" objects such as Fixnum from within callbacks & al...

> Here's the problem: it happens often that you need to pass "references" to
> objects so that callbacks/functions/etc may modify these objects to their
> convenience, and you will need the modified value afterwards.
>
> Now with "immutable" objects such as Fixnum (also described as objects
> that have "immediate" values by the pickaxe book --> you can't mutate a
> given instance) I can't directly do that... and since "everything" is
> references in Ruby I don't know how to pass a reference to a Fixnum apart
> doing the following, that is an object which is basically a container
> holding one object (o) :
>

You do understand that because Fixnums are immutable, that the instance that
ObjContainer.o refers to is actually a *different* object after the doit_()
method processes it, right? That is to say, if you were to compare the
object id of ObjContainer.o before and after calling doit_(), you'd get
different ids.

Assuming you're OK with that, and if the function is really as simple as
your doit_() example, you might as well have doit_() take a Fixnum as input
and return the (new) Fixnum as its result.