From: Austin Ziegler <halostatue@...>
Date: 2005-12-30T14:45:55+09:00
Subject: Re: What is the difference between :foo and "foo" ?

On 29/12/05, Devin Mullins <twifkak@comcast.net> wrote:
> Austin Ziegler wrote:
> >The Symbol is just a name.
> Er... a thing that /has/ a name. (That being, Symbol#to_s.)

No, I think that the essential property of a Symbol is that it is an
object that is a name:

  keep = Symbol.all_symbols
  quuxl = nil
  puts Symbol.all_symbols - keep

You'll see that :quuxl is there. You can get a string representation
of that name (:quuxl.to_s) or an integer representation of that name
(:quuxl.to_i), but the canonical representation of that name is the
Symbol itself (:quuxl). Sure, you could get pedantically
philosophical, but the you'd be saying that 1 really isn't the number,
it's a thing that represents a quantity of one.

For all practical purposes, Symbols are atomic in the sense that they
are themselves. Who *cares* how it's actually represented in the
implementation? That can change. The fundamental nature of a Symbol is
that :quuxl will always be :quuxl and never anything else. Consider
these two IRB sessions:

irb(main):001:0> :bar.to_i
=> 23417
irb(main):002:0> :quuxl.to_i
=> 23425
irb(main):003:0>

irb(main):001:0> :quuxl.to_i
=> 23417
irb(main):002:0> :bar.to_i
=> 23425
irb(main):003:0>

A Symbol, like a number, is immediate and is identified by itself.

-austin
--
Austin Ziegler * halostatue@gmail.com
               * Alternate: austin@halostatue.ca