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A weird thing about Arrays

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Ricardo Moran

A weird thing about Arrays

Hi, guys

I'm sorry if what I'm about to ask is a newbie question but I'm puzzled about a behavior I found today regarding Arrays.

a1 := #(0 0 0 0).

a2 := #(0 0 0 0).

a1 == a2

If I select the whole expression above and execute it on a workspace it returns true (meaning that a1 and a2 are the same object). If I execute each line separately it returns false.

I don't understand why this happens. Is this expected? or is it a bug?

This only happens when I use the literal syntax, using Array >> #new:withAll: works fine regardless of the way I execute it. I'm inclined to think this is a bug, but I wanted to know what you think about it.

Cheers

Richo

Levente Uzonyi-2

Re: A weird thing about Arrays

On Fri, 12 Mar 2010, Ricardo Moran wrote:

> Hi, guys
>
> I'm sorry if what I'm about to ask is a newbie question but I'm puzzled
> about a behavior I found today regarding Arrays.
>
> a1 := #(0 0 0 0).
> a2 := #(0 0 0 0).
> a1 == a2
>
> If I select the whole expression above and execute it on a workspace it
> returns true (meaning that a1 and a2 are the same object). If I execute each
> line separately it returns false.
> I don't understand why this happens. Is this expected? or is it a bug?
>
> This only happens when I use the literal syntax, using Array >>
> #new:withAll: works fine regardless of the way I execute it. I'm inclined to
> think this is a bug, but I wanted to know what you think about it.

It's an optimization by the compiler. If the same literal object appears
twice or more, only one object will be created.

Levente

>
> Cheers
> Richo
>

Ricardo Moran

Re: A weird thing about Arrays

Oh, I wish I knew that before!

I lost a lot of time thinking some magic stuff was messing with my arrays :P

On Fri, Mar 12, 2010 at 6:45 PM, Levente Uzonyi <[hidden email]> wrote:

On Fri, 12 Mar 2010, Ricardo Moran wrote:

Hi, guys

I'm sorry if what I'm about to ask is a newbie question but I'm puzzled
about a behavior I found today regarding Arrays.

a1 := #(0 0 0 0).
a2 := #(0 0 0 0).
a1 == a2

If I select the whole expression above and execute it on a workspace it
returns true (meaning that a1 and a2 are the same object). If I execute each
line separately it returns false.
I don't understand why this happens. Is this expected? or is it a bug?

This only happens when I use the literal syntax, using Array >>
#new:withAll: works fine regardless of the way I execute it. I'm inclined to
think this is a bug, but I wanted to know what you think about it.

It's an optimization by the compiler. If the same literal object appears twice or more, only one object will be created.

Levente

Cheers
Richo