From: Steve Litt <slitt@...>
Date: 2005-12-30T02:08:33+09:00
Subject: Re: What is the difference between :foo and "foo" ?

On Thursday 29 December 2005 11:20 am, Kirk Haines wrote:
> On Thursday 29 December 2005 8:45 am, Steve Litt wrote:
> > They wouldn't exist, or they wouldn't be called symbols. If I'm referring
> > to an instance instead of a value, I could call it &variable as in C, or
> > I could call it :variable, but in that case I'd call it a reference, not
> > a symbol.
>
> It's not a reference.  Symbols are much simpler than that.  Really.  They
> are just an integer with some sequence of characters to represent it, all
> wrapped up in an object.

OK, let me see if I'm correctly understanding you.

:wilbur is an object. That object has two properties, which one could call, in 
generic and not Ruby terms, a key and a value. The key is an integer. The 
value is "wilbur". Neither the key nor the value can be changed during the 
execution of the program. When we write:

attr_accessor :wilbur

what really happens is that the function attr_accessor() takes symbol :wilbur 
as an argument, tacks on a @ to the string's value in order to make the true 
class variable @wilbur, and then writes a tiny get and set functions whose 
names are wilbur, such that:

my_object.wilbur = 22
puts my_object.wilbur

So my initial comment that it seemed like magic is true only to the extent 
that the "magic" performed by attr_accessor is to create the set and get 
methods with the same name as the symbol that is its argument.

Do I understand what you're saying?

Thanks

SteveT

Steve Litt
http://www.troubleshooters.com
slitt@troubleshooters.com