From: Brandon Dimcheff <bdimchef@...>
Date: 2008-10-08T00:32:41+09:00
Subject: Re: Difference between Foo = Class.new and class Foo

matz,

I don't think I'm doing conceptually different things below.  I'm  
looking at creating and defining classes, not creating objects from  
those classes.  I'm attempting to create a class called Foo in both  
cases.  The first time, I use the class keyword.  The second time, I  
call Class.new.  It seems that using the class keyword doesn't call  
Class's metaclass's "new" method, while Class.new (obviously) does.

Thanks,
Brandon

On Oct 7, 2008, at 10:57, Yukihiro Matsumoto wrote:

> Hi,
>
> In message "Re: Difference between Foo = Class.new and class Foo"
>    on Tue, 7 Oct 2008 23:51:03 +0900, Brandon Dimcheff <bdimchef@wieldim.com 
> > writes:
>
> |I'm playing around with classes and discovered that
> |
> |class Foo
> |   ...
> |end
> |
> |and
> |
> |Foo = Class.new do
> |   ...
> |end
> |
> |seem to behave slightly differently.  I assumed that "class Foo" was
> |just a shortcut that got translated into "Foo = Class.new", but  
> when I
> |muck with class in the following way:
> |
> |class Class
> |   class << self
> |     def new
> |       puts "new called"
> |       super
> |     end
> |   end
> |end
> |
> |and then do "Foo = Class.new",  I get "new called" printed to stdout.
> |If I do "class Foo..." I get nothing.  So it seems that the "class"
> |keyword does not end up calling new on Class when you define a new
> |class.  Does anybody know what's going on here?  Is something else
> |called instead?
>
> I think you're comparing the different code.  See the following code:
>
> class Foo
>   class << self
>     def new
>       puts "foo new called"
>       super
>     end
>   end
> end
>
> Foo.new
>
>
> Bar = Class.new do
>   class << self
>     def new
>       puts "bar new called"
>       super
>     end
>   end
> end
>
> Bar.new
> -- 
> 							matz.
>