From: Devin Mullins <twifkak@...>
Date: 2005-12-29T11:31:22+09:00
Subject: Re: What is the difference between :foo and "foo" ?

Jim Weirich wrote:

>I'm not sure if this helped, or just muddied the water more.
>  
>
When I first was trying to learn about symbols, attempts to explain 
their "intentions" (as names of things, for example), rather than to 
explain what they are, just muddied the water for me. Sure, give me some 
advice on when and when not to use them, but also, tell me what they 
are, so I can decide for myself:
- Like a string, but:
- Object-level equality, so :foo.equal?(:foo) and not 'foo'.equal?('foo')
- That means, with strings, if you say 'foo' 5 times in the code, you're 
creating 5 string objects, whereas with symbols, you're only creating one.
- Share many properties with Fixnum (both being "immediate")-- 
immutable, no singleton classes, object equality, not picked up by 
ObjectSpace.each_object...
- Not garbage collected.
- Looks cooler -- by using a different syntax, you can give some visual 
distinction between your keys and your values, for instance.

(Also, Johannes Friestad's explanation was pretty good, IMO.)

Devin