From: Robert Klemme <shortcutter@...>
Date: 2008-10-16T23:59:35+09:00
Subject: Re: what is [] here

On 16.10.2008 16:13, Serabe wrote:
> 2008/10/16 Raj Singh <neeraj.jsr@...>:
>> What does it mean to have [] method at a class level? Where is the
>> documentation for it?
> 
> It is the empty array. Just type
> 
> [].class => Array
> [].size => 0

It is not _the_ empty Array but _an_ empty Array.  Things like [], "" 
and '' are actually constructors for new objects.  This is important to 
keep in mind.  Especially people coming from Java might get the wrong 
impression, that

a = "foo"
b = "foo"

will create two variables pointing to the same object.  In reality, 
there are two variables pointing to two different objects.  You can 
easily see that from

$ ruby -e '4.times do p [[],"",'\'\''].map {|o|o.object_id} end'
[134314000, 134313990, 134313980]
[134313890, 134313880, 134313870]
[134313790, 134313780, 134313770]
[134313690, 134313680, 134313670]


Kind regards

	robert