From: Steve Litt <slitt@...>
Date: 2005-12-31T05:40:21+09:00
Subject: Re: What is the difference between :foo and "foo" ?

On Friday 30 December 2005 03:29 pm, Kirk Haines wrote:
> On Friday 30 December 2005 1:03 pm, Austin Ziegler wrote:
> > Please edit your guide, as it is *not* correct when it says:
> >
> >    A Ruby symbol is a thing that has both a number (integer) and a
> > string.
> >
> > This is not correct in any way. If you leave it as "A Ruby Symbol is a
> > thing", you're fine. But when you say that it "has" a number and a
> > string, you are incorrect. Symbols are not composed of the integer or
> > string values that you can convert Symbols to; they just are. The
> > value of a Symbol is not its String value or its Fixnum value, but
> > itself.
>
> I think that I am probably the source for this confusion, and I am guilty
> of not clarifying further what I meant.
>
> :foo is a symbol.  The string representation of :foo is 'foo'.
> :
> :foo.to_s
> :
> :foo also has an integer that id, found with #object_id:
> :
> :foo.object_id
>
> This is no different than any other object.  What is different is this:
>
> irb(main):001:0> 'foo'.object_id
> => -609482574
> irb(main):002:0> 'foo'.object_id
> => -609486184
> irb(main):003:0> 'foo'.object_id
> => -609489724
>
> The id changes because each 'foo' is a different object.
>
> irb(main):004:0> :foo.object_id
> => 3957006
> irb(main):005:0> :foo.object_id
> => 3957006
> irb(main):006:0> :foo.object_id
> => 3957006
>
> The id doesn't change because :foo is just :foo -- it's the same object
> every time.
>
>
> Kirk Haines

Hi Kirk,

I could swear that's exactly what I said in the Ruby Newbie Guide to Symbols. 
I like your code-centric way of saying it, though.

SteveT

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