From: Mathieu Bouchard <matju@...>
Date: 2001-07-10T07:30:14+09:00
Subject: [ruby-talk:17561] Re: Constants and Variables


On Tue, 10 Jul 2001, Martin J. Laubach wrote:
>   The first point is the definition of constants (a symbol starting
> with an upper case letter) -- WTF was it done that way, mixing
> syntax and semantics, instead of having a "const" attribute.

What are called "constants" in Ruby is a namespace (or really, a graph of
namespaces), just like there is the global namespace ($), the object
namespace (@), the local namespaces, the method namespaces.

The constants namespaces are made to hold classes by name and such. 
(global namespace is for stuff that *really* is global.) 

> After all, if you go down that way, ruby could define protected methods
> as "starting with an underscore" or such. 

Well, it can as well not do that too. You can drink one beer, and the step
to a second beer is not hard to walk, but some people actually are willing
to drink *exactly* one beer. You see? =)

>   I'd rather have a const attribute which makes the object immutable.

If you want objects that don't change, try Object#freeze, Object#frozen?.

>   One of the other things I miss dearly is a way to create a new
> block-local variable. I have been bitten by

creating a local variable is an implicit thing that happens upon
assignment. local variable is searched in current namespace and
recursively in its parents, then if not found, is created in the current.

block parameter passing is assignment, single or multiple.

matju