# Pointer concept in Ruby?

**URL:** <https://rubytalk.org/t/pointer-concept-in-ruby/46097>\
**Category:** ruby-talk\
**Created:** [24 April 2008 16:01 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097 "2008-04-24T16:01:00Z")\
**Posts on this page:** 16\
**Page:** 1

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 16:01 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/1 "2008-04-24T16:01:00Z")

</div>

Hi, I'd like to have a variable pointing to a Hash/Array element, so  
if I modify the variable then the Hash/Array element is modified too.

AFAIK this is not possible with Ruby since the abscense of pointer  
concept. I want the following:

&nbsp;&nbsp;array = ["aaa", "bbb", "ccc"]

&nbsp;&nbsp;a1 = array[1].\_some\_method\_  
&nbsp;&nbsp;=\> "bbb"

&nbsp;&nbsp;a1 = "BBB"  
&nbsp;&nbsp;=\> "BBB"

&nbsp;&nbsp;a[1]  
&nbsp;&nbsp;=\> "BBB"

Is it possible in some way? Thanks a lot.

> **···**
>
> --  
> Iñaki Baz Castillo  
> \<[ibc@aliax.net](mailto:ibc@aliax.net)\>

---

<div class="post-metadata">

**Author:** ![Mikael\_Hoilund](https://avatars.discourse-cdn.com/v4/letter/m/c37758/32.png) [@Mikael\_Hoilund](https://rubytalk.org/u/Mikael_Hoilund)\
**Post date:** [24 April 2008 16:07 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/2 "2008-04-24T16:07:58Z")

</div>

> Hi, I'd like to have a variable pointing to a Hash/Array element, so  
> if I modify the variable then the Hash/Array element is modified too.
> 
> AFAIK this is not possible with Ruby since the abscense of pointer  
> concept. I want the following:
> 
> array = ["aaa", "bbb", "ccc"]
> 
> a1 = array[1].\_some\_method\_  
> =\> "bbb"
> 
> a1 = "BBB"  
> =\> "BBB"
> 
> a[1]  
> =\> "BBB"
> 
> Is it possible in some way? Thanks a lot.
> 
> -- Iñaki Baz Castillo  
> \<ibc@aliax.net\>

Quoth irb:

\>\> array = ["aaa", "bbb", "ccc"]  
=\> ["aaa", "bbb", "ccc"]  
\>\> a1 = array[1]  
=\> "bbb"  
\>\> a1.upcase!  
=\> "BBB"  
\>\> array  
=\> ["aaa", "BBB", "ccc"]  
\>\>

You never pass by value, so you're in essence always dealing with pointers.  
With your example, you merely made a1 point at a different object, a new string, instead of the second string in the array.

If you however call a self-modifying method on a1 while it's pointing at the array string, it'll also change in the array, as it's still pointing at the same object.

What are you trying to achieve in practice?

> **···**
>
> On Apr 24, 2008, at 18:01, Iñaki Baz Castillo wrote:

---

<div class="post-metadata">

**Author:** ![Bill\_Kelly](https://avatars.discourse-cdn.com/v4/letter/b/cc9497/32.png) [@Bill\_Kelly](https://rubytalk.org/u/Bill_Kelly)\
**Post date:** [24 April 2008 16:16 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/3 "2008-04-24T16:16:11Z")

</div>

> Hi, I'd like to have a variable pointing to a Hash/Array element, so  
> if I modify the variable then the Hash/Array element is modified too.
> 
> AFAIK this is not possible with Ruby since the abscense of pointer  
> concept. I want the following:
> 
> array = ["aaa", "bbb", "ccc"]
> 
> a1 = array[1].\_some\_method\_  
> =\> "bbb"
> 
> a1 = "BBB"  
> =\> "BBB"
> 
> a[1]  
> =\> "BBB"
> 
> Is it possible in some way? Thanks a lot.

In general this not easily possible with Ruby, and you'll probably want to  
rethink your design so that you don't need to do that.

However, there is a String#replace method, which may be useful if you're  
sure this is what you want to do:

=\> ["aaa", "bbb", "ccc"]

> > a1 = array[1]

=\> "bbb"

> > a1.replace "BBB"

=\> "BBB"

> > array[1]

=\> "BBB"

Regards,

Bill

> **···**
>
> From: "Iñaki Baz Castillo" \<ibc@aliax.net\>

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 16:24 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/4 "2008-04-24T16:24:36Z")

</div>

> \> Hi, I'd like to have a variable pointing to a Hash/Array element, so  
> \> if I modify the variable then the Hash/Array element is modified too.  
> \>  
> \> AFAIK this is not possible with Ruby since the abscense of pointer  
> \> concept. I want the following:  
> \>  
> \> array = ["aaa", "bbb", "ccc"]  
> \>  
> \> a1 = array[1].\_some\_method\_  
> \> =\> "bbb"  
> \>  
> \> a1 = "BBB"  
> \> =\> "BBB"  
> \>  
> \> a[1]  
> \> =\> "BBB"  
> \>  
> \> Is it possible in some way? Thanks a lot.  
> \>  
> \>  
> \> -- Iñaki Baz Castillo  
> \> \<ibc@aliax.net\>  
> \>
> 
> Quoth irb:
> 
> \>\> array = ["aaa", "bbb", "ccc"]  
> =\> ["aaa", "bbb", "ccc"]  
> \>\> a1 = array[1]  
> =\> "bbb"  
> \>\> a1.upcase!  
> =\> "BBB"  
> \>\> array  
> =\> ["aaa", "BBB", "ccc"]  
> \>\>
> 
> You never pass by value, so you're in essence always dealing with pointers.  
> With your example, you merely made a1 point at a different object, a new  
> string, instead of the second string in the array.

Yes, I know that since object\_id is the same \*\*until\*\* a write  
operation is done.

> If you however call a self-modifying method on a1 while it's pointing at  
> the array string, it'll also change in the array, as it's still pointing at  
> the same object.

No, that's not true. Demostration:

array=[000,111,222,33]  
=\> [0, 111, 222, 33]

a1=a[1]  
=\> 1

a[1].object\_id  
=\> 345

a1.object\_id  
=\> 345

a1="NEW VALUE"  
=\> "NEW VALUE"

> a1.object\_id

=\> -606081098 \<----------- Has changed !!!

a[1].object\_id \<-------- Remains the same  
=\> 345

a1  
=\> "NEW VALUE"

a[1]  
=\> 1 \<----------- Original value not changed

> What are you trying to achieve in practice?

In fact just the code I wrote as example 🙂

> **···**
>
> 2008/4/24, Mikael Høilund \<mikael@hoilund.org\>:
> 
> > On Apr 24, 2008, at 18:01, Iñaki Baz Castillo wrote:
> 
> --  
> Iñaki Baz Castillo  
> \<ibc@aliax.net\>

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 16:30 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/5 "2008-04-24T16:30:17Z")

</div>

Oh, really curious but I don't like it since it's just valid for  
strings (why??) and it requires variable to be already defined. Isn't  
there any mehotd more "normal"? something as:

a2 = array[2].\_something\_

a2="QWE"

array[2]  
=\> "QWE"

Thanks a lot.

> **···**
>
> 2008/4/24, Bill Kelly \<billk@cts.com\>:
> 
> > However, there is a String#replace method, which may be useful if you're  
> > sure this is what you want to do:
> > 
> > =\> ["aaa", "bbb", "ccc"]
> > 
> > \>  
> > \> \> a1 = array[1]  
> > \> \>  
> > \>  
> > =\> "bbb"
> > 
> > \>  
> > \> \> a1.replace "BBB"  
> > \> \>  
> > \>  
> > =\> "BBB"
> > 
> > \>  
> > \> \> array[1]  
> > \> \>  
> > \>  
> > =\> "BBB"
> 
> --  
> Iñaki Baz Castillo  
> \<ibc@aliax.net\>

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 16:26 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/6 "2008-04-24T16:26:26Z")

</div>

> No, that's not true. Demostration:
> 
> array=[000,111,222,33]  
> =\> [0, 111, 222, 33]

Sorry, it was:

a=[0,1,2,3]

> **···**
>
> 2008/4/24, Iñaki Baz Castillo \<ibc@aliax.net\>:
> 
> > a1=a[1]  
> > =\> 1
> > 
> > a[1].object\_id  
> > =\> 345
> > 
> > a1.object\_id  
> > =\> 345
> > 
> > a1="NEW VALUE"  
> > =\> "NEW VALUE"
> > 
> > \> a1.object\_id  
> > =\> -606081098 \<----------- Has changed !!!
> > 
> > a[1].object\_id \<-------- Remains the same  
> > =\> 345
> > 
> > a1  
> > =\> "NEW VALUE"
> > 
> > a[1]  
> > =\> 1 \<----------- Original value not changed
> 
> --  
> Iñaki Baz Castillo  
> \<ibc@aliax.net\>

---

<div class="post-metadata">

**Author:** ![Kirk\_Haines](https://avatars.discourse-cdn.com/v4/letter/k/c6cbf5/32.png) [@Kirk\_Haines](https://rubytalk.org/u/Kirk_Haines)\
**Post date:** [24 April 2008 16:41 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/7 "2008-04-24T16:41:31Z")

</div>

> Yes, I know that since object\_id is the same \*\*until\*\* a write  
> operation is done.
> 
> > If you however call a self-modifying method on a1 while it's pointing at  
> > the array string, it'll also change in the array, as it's still pointing at  
> > the same object.
> 
> No, that's not true. Demostration:
> 
> array=[000,111,222,33]  
> =\> [0, 111, 222, 33]
> 
> a1=a[1]  
> =\> 1
> 
> a[1].object\_id  
> =\> 345
> 
> a1.object\_id  
> =\> 345
> 
> a1="NEW VALUE"  
> =\> "NEW VALUE"
> 
> > a1.object\_id
> 
> =\> -606081098 \<----------- Has changed !!!

Because you changed the object that a1 points to.

> a[1].object\_id \<-------- Remains the same  
> =\> 345

a[1] points to an object.  
a1 points to an object.

They were the same object, until you pointed a1 at a different object.

This is the important distinction that you are missing.

To recap:

a = [1,2,3,4]

a points to an Array that contains 4 objects, the Fixnums 1, 2, 3, and 4.

a[1] calls a method on the object pointed to by 'a'. That method returns the object in the 1 position in the array.

a1 = a[1] points 'a1' at that object. a1 is just a pointer, though, to an object.

You can't change what the Array pointed to by 'a' contains by pointing 'a1' at a different object, which is what your assignment of "NEW STRING" to 'a1' did.

If you want to change what is stored in the 1 index position in the Array pointed to by 'a', you need to be operating on that Array.

b = a  
b[1] = "another new string"  
puts a[1]

another new string

Make sense?

Kirk Haines

> **···**
>
> On Fri, 25 Apr 2008, [UTF-8] Iñaki Baz Castillo wrote:

---

<div class="post-metadata">

**Author:** ![Simon\_Krahnke](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Simon\_Krahnke](https://rubytalk.org/u/Simon_Krahnke)\
**Post date:** [24 April 2008 18:35 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/8 "2008-04-24T18:35:04Z")

</div>

\* Iñaki Baz Castillo \<ibc@aliax.net\> (18:24) schrieb:

> > If you however call a self-modifying method on a1 while it's pointing at  
> > the array string, it'll also change in the array, as it's still pointing at  
> > the same object.
> 
> No, that's not true. Demostration:

You aren't calling a "self-modifying method".

mfg, simon .... l

---

<div class="post-metadata">

**Author:** ![Simon\_Krahnke](https://avatars.discourse-cdn.com/v4/letter/s/b782af/32.png) [@Simon\_Krahnke](https://rubytalk.org/u/Simon_Krahnke)\
**Post date:** [24 April 2008 18:35 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/9 "2008-04-24T18:35:09Z")

</div>

\* Iñaki Baz Castillo \<ibc@aliax.net\> (18:30) schrieb:

> a2 = array[2].\_something\_
> 
> a2="QWE"
> 
> array[2]  
> =\> "QWE"

You can't redefine =.

mfg, simon .... l

---

<div class="post-metadata">

**Author:** ![Adam\_Shelly](https://avatars.discourse-cdn.com/v4/letter/a/e19b73/32.png) [@Adam\_Shelly](https://rubytalk.org/u/Adam_Shelly)\
**Post date:** [24 April 2008 20:54 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/10 "2008-04-24T20:54:55Z")

</div>

There are probabaly a million reasons this is a bad idea, but what about:

require 'ptrclass'  
=\> true  
a = [0,1,2,3]  
=\> [0, 1, 2, 3]  
ap = a.ptr(3)  
=\> 3  
ap.val=4  
=\> 4  
a  
=\> [0, 1, 2, 4]  
r=a.ptr(6)  
=\> nil  
r.val=4  
=\> 4  
a  
=\> [1, 34, 3, nil, nil, nil, 4]

--- ptrclass.rb----  
class PtrClass \< DelegateClass(Object)  
&nbsp;&nbsp;def initialize v  
&nbsp;&nbsp;&nbsp;&nbsp;super  
&nbsp;&nbsp;&nbsp;&nbsp;\_\_setobj\_\_ v  
&nbsp;&nbsp;end  
&nbsp;&nbsp;def val= v  
&nbsp;&nbsp;&nbsp;&nbsp;\_\_setobj\_\_ v  
&nbsp;&nbsp;end  
end  
class Array  
&nbsp;&nbsp;def ptr n  
&nbsp;&nbsp;&nbsp;&nbsp;v= self[n]  
&nbsp;&nbsp;&nbsp;&nbsp;self[n] = v.is\_a?(PtrClass) ? v : PtrClass.new(v)  
&nbsp;&nbsp;end  
end

> **···**
>
> On 4/24/08, Iñaki Baz Castillo \<ibc@aliax.net\> wrote:
> 
> > Isn't there any mehotd more "normal"? something as:
> > 
> > a2 = array[2].\_something\_
> > 
> > a2="QWE"
> > 
> > array[2]  
> > =\> "QWE"
> 
> ---  
> -Adam

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 16:55 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/11 "2008-04-24T16:55:30Z")

</div>

> They were the same object, until you pointed a1 at a different object.
> 
> This is the important distinction that you are missing.
> 
> To recap:
> 
> a = [1,2,3,4]
> 
> a points to an Array that contains 4 objects, the Fixnums 1, 2, 3, and 4.
> 
> a[1] calls a method on the object pointed to by 'a'. That method  
> returns the object in the 1 position in the array.
> 
> a1 = a[1] points 'a1' at that object. a1 is just a pointer, though, to an  
> object.
> 
> You can't change what the Array pointed to by 'a' contains by pointing 'a1'  
> at a different object, which is what your assignment of "NEW STRING" to 'a1'  
> did.
> 
> If you want to change what is stored in the 1 index position in the Array  
> pointed to by 'a', you need to be operating on that Array.
> 
> b = a  
> b[1] = "another new string"  
> puts a[1]
> 
> another new string
> 
> Make sense?

Sure, but I already kwen it, note that I was answering to Mikael that said:

> If you however call a self-modifying method on a1 while it's pointing at the array string, it'll also  
> change in the array, as it's still pointing at the same object.

But thanks for the explanation 🙂

> **···**
>
> 2008/4/24, khaines@enigo.com \<khaines@enigo.com\>:
> 
> --  
> Iñaki Baz Castillo  
> \<ibc@aliax.net\>

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 21:43 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/12 "2008-04-24T21:43:07Z")

</div>

It seems magic, thanks a lot.

> **···**
>
> El Jueves, 24 de Abril de 2008, Adam Shelly escribió:
> 
> > There are probabaly a million reasons this is a bad idea, but what about:
> > 
> > require 'ptrclass'  
> > =\> true  
> > a = [0,1,2,3]  
> > =\> [0, 1, 2, 3]  
> > ap = a.ptr(3)  
> > =\> 3  
> > ap.val=4  
> > =\> 4  
> > a  
> > =\> [0, 1, 2, 4]  
> > r=a.ptr(6)  
> > =\> nil  
> > r.val=4  
> > =\> 4  
> > a  
> > =\> [1, 34, 3, nil, nil, nil, 4]
> > 
> > --- ptrclass.rb----  
> > class PtrClass \< DelegateClass(Object)  
> > &nbsp;&nbsp;def initialize v  
> > &nbsp;&nbsp;&nbsp;&nbsp;super  
> > &nbsp;&nbsp;&nbsp;&nbsp;\_\_setobj\_\_ v  
> > &nbsp;&nbsp;end  
> > &nbsp;&nbsp;def val= v  
> > &nbsp;&nbsp;&nbsp;&nbsp;\_\_setobj\_\_ v  
> > &nbsp;&nbsp;end  
> > end  
> > class Array  
> > &nbsp;&nbsp;def ptr n  
> > &nbsp;&nbsp;&nbsp;&nbsp;v= self[n]  
> > &nbsp;&nbsp;&nbsp;&nbsp;self[n] = v.is\_a?(PtrClass) ? v : PtrClass.new(v)  
> > &nbsp;&nbsp;end  
> > end
> 
> --  
> Iñaki Baz Castillo

---

<div class="post-metadata">

**Author:** ![Kirk\_Haines](https://avatars.discourse-cdn.com/v4/letter/k/c6cbf5/32.png) [@Kirk\_Haines](https://rubytalk.org/u/Kirk_Haines)\
**Post date:** [24 April 2008 17:04 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/13 "2008-04-24T17:04:54Z")

</div>

If you already knew it, what is the confusion? You misunderstood what he said. He said:

"If you however call a self-modifying method on a1 while it's pointing at the array string, it'll also change in the array, as it's still pointing at the same object."

Note the "self-modifying" words there.

In your example, you weren't changing what a1 pointed to; you were not changing anything about the object itself.

irb(main):001:0\> a = ['0','1','2','3']  
=\> ["0", "1", "2", "3"]  
irb(main):002:0\> a[1]  
=\> "1"  
irb(main):003:0\> a1 = a[1]  
=\> "1"  
irb(main):004:0\> a1 \<\< 'abc'  
=\> "1abc"  
irb(main):005:0\> a[1]  
=\> "1abc"

This is what he meant by "self-modifying" methods. Methods that change something about the object itself.

Kirk Haines

> **···**
>
> On Fri, 25 Apr 2008, [UTF-8] Iñaki Baz Castillo wrote:
> 
> > Sure, but I already kwen it, note that I was answering to Mikael that said:
> > 
> > > If you however call a self-modifying method on a1 while it's pointing at the array string, it'll also  
> > > change in the array, as it's still pointing at the same object.
> > 
> > But thanks for the explanation 🙂

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [24 April 2008 21:22 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/14 "2008-04-24T21:22:48Z")

</div>

Really thanks. You are right, I didn't understand the meaning  
of "self-modifying" method, I thought that "=" was also a "self-modifying"  
method.

Sorry for the confusion and thanks a lot.

> **···**
>
> El Jueves, 24 de Abril de 2008, khaines@enigo.com escribió:
> 
> > In your example, you weren't changing what a1 pointed to; you were not  
> > changing anything about the object itself.
> > 
> > irb(main):001:0\> a = ['0','1','2','3']  
> > =\> ["0", "1", "2", "3"]  
> > irb(main):002:0\> a[1]  
> > =\> "1"  
> > irb(main):003:0\> a1 = a[1]  
> > =\> "1"  
> > irb(main):004:0\> a1 \<\< 'abc'  
> > =\> "1abc"  
> > irb(main):005:0\> a[1]  
> > =\> "1abc"
> > 
> > This is what he meant by "self-modifying" methods. Methods that change  
> > something about the object itself.
> 
> --  
> Iñaki Baz Castillo

---

<div class="post-metadata">

**Author:** ![Sebastian\_Hungereck1](https://avatars.discourse-cdn.com/v4/letter/s/3ab097/32.png) [@Sebastian\_Hungereck1](https://rubytalk.org/u/Sebastian_Hungereck1)\
**Post date:** [25 April 2008 07:47 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/15 "2008-04-25T07:47:31Z")

</div>

Iñaki Baz Castillo wrote:

> I thought that "=" was also a "self-modifying"  
> method.

= isn't a method. If it was a method, x=y could not result in x having a  
different object\_id than before. It could also not result in x having a  
different class than before.  
What x = y does, is that it makes x point to the same object as y which  
doesn't affect the old object x pointed to at all.  
Basically methods change the object (or not) and = changes the variable.  
I don't think it's possible to have a = method without static typing.

Note though that in "foo.bar = baz" bar= actually is a method on foo and not  
an assignment operation.

HTH,  
Sebastian

> **···**
>
> --  
> NP: Depeche Mode - Little 15  
> Jabber: sepp2k@jabber.org  
> ICQ: 205544826

---

<div class="post-metadata">

**Author:** ![Inaki\_Baz\_Castillo](https://avatars.discourse-cdn.com/v4/letter/i/f14d63/32.png) [@Inaki\_Baz\_Castillo](https://rubytalk.org/u/Inaki_Baz_Castillo)\
**Post date:** [25 April 2008 09:09 UTC](https://rubytalk.org/t/pointer-concept-in-ruby/46097/16 "2008-04-25T09:09:20Z")

</div>

Thanks for the explanation.

I tryed doing:

&nbsp;&nbsp;a2.object\_id = array[2].object\_id

but obviously is not permitted XDDD

> **···**
>
> 2008/4/25, Sebastian Hungerecker \<sepp2k@googlemail.com\>:
> 
> > Iñaki Baz Castillo wrote:  
> > \> I thought that "=" was also a "self-modifying"  
> > \> method.
> > 
> > = isn't a method. If it was a method, x=y could not result in x having a  
> > different object\_id than before. It could also not result in x having a  
> > different class than before.  
> > What x = y does, is that it makes x point to the same object as y which  
> > doesn't affect the old object x pointed to at all.  
> > Basically methods change the object (or not) and = changes the variable.  
> > I don't think it's possible to have a = method without static typing.
> > 
> > Note though that in "foo.bar = baz" bar= actually is a method on foo and not  
> > an assignment operation.
> 
> --  
> Iñaki Baz Castillo  
> \<ibc@aliax.net\>