From: wangqianpku@...
Date: 2007-10-05T10:50:03+09:00
Subject: Re: a = Dog.new # a is not a pointer and not a reference?

On Sep 30, 1:16 am, SpringFlowers AutumnMoon
<summercooln...@gmail.com> wrote:
> when we say
>
> a = Dog.new("lulu")
>
> Now a is not really a pointer, because we don't need to dereference it
> to use it, like
>
> (*a).color = "red"
> a->color = "red"
>
> When we use a.color, it is like a reference in C++ implicitly
> dereference it and use its attributes.
>
> But then a is not really a reference (like C++), because we can say
>
> a = nil  or   a = Dog.new("woofy")
>
> and now a points to some where else.  With reference, once a reference
> is set, it cannot point to some where else  (in C++).
>
> So it is kind of a mixture of pointer and reference?
>
> Or, we can think of it as a pointer, and then think of "." as the "->"
> in C++.
>
> In that case, we can say that a is a pointer and not a reference.
>
> And it seems the same way in Java, Python, and PHP5.
>
> (Pointers and References discussed in
>
> http://en.wikipedia.org/wiki/Reference_%28computer_science%29http://en.wikipedia.org/wiki/Reference_%28C%2B%2B%29
>
> )
> --
> Posted viahttp://www.ruby-forum.com/.

Yes! You're right.
It's really not "reference" or "value" or "pointer" in c++ sense.

Some body calls it "reference to object" or something else.
Anyway, if you want to use conceptions in c++ sense to describe it.
It works like (i said somewhere before)....
when it's used as a left value, it works like a pointer, which means
the variable doesn't have the object. it only points to the object.
when it's used as a right value, it dereference automatically.