From: dblack@...
Date: 2006-01-05T09:57:34+09:00
Subject: Re: On Symbols

Hi --

On Thu, 5 Jan 2006, Jim Weirich wrote:

> DAB wrote:
>> Fixnums, Symbols, true, false, and nil get assigned directly to
>> variables.  For other objects, variables get a reference to the
>> object.  References, like variables, are not themselves objects.
>> They're part of a kind of language substratum on which the object
>> system floats.
>
> True, but ...
>
>> [...] In fact, in a sense there's even
>> less to it, since Ruby handles any necessary de-referencing for you,
>> so you don't have to make any explicit distinction in your code.
>
> I think that this second statement is much more important than the
> first.  The fact that 1073741823 is direct and 1073741824 is a reference
> makes very little difference 99.99% of the time.
>
> Understanding that Fixnums, Symbols and the such are direct is good for
> groking implementation details, but provides little insight in using
> Ruby.  The fact we can pretend that everything is a reference is a
> marvelous feature of the Ruby object model.

It is indeed.  I think one reason I'm so immediate-value-aware is the
history of discussions of ++, the absence of which makes sense in
light of the immediate value thing (with numbers).  And I guess I'd
put that at a middle level -- not something you really need to know to
use Ruby, but not quite an implementation detail either; more of a
language design thing.


David

-- 
David A. Black
dblack@wobblini.net

"Ruby for Rails", from Manning Publications, coming April 2006!
http://www.manning.com/books/black