[Rails] [ANN] "Ruby for Rails" now available in PDF!

dblack@wobblini.net
Tue, 18 Apr 2006 14:22:18 -0000

Hi --

On Tue, 18 Apr 2006, Ken Kousen wrote:

> Of course, that''s another trap.  In Java, the words "instance
variables" and
> "attributes" are interchangeable. :)

Think of them not as traps but as releases *from* traps :-)


David


> Ken
>
> --
> Kenneth A. Kousen, Ph.D.
> President
> Kousen IT, Inc.
> http://www.kousenit.com
> ken.kousen@kousenit.com
> -----Original Message-----
> From: rails-bounces@lists.rubyonrails.org
> [mailto:rails-bounces@lists.rubyonrails.org] On Behalf Of
> dblack@wobblini.net
> Sent: Monday, April 17, 2006 11:30 PM
> To: rails@lists.rubyonrails.org
> Subject: RE: [Rails] [ANN] "Ruby for Rails" now available in PDF!
>
> Hi --
>
> On Mon, 17 Apr 2006, Ken Kousen wrote:
>
>> 3. If you declare an attribute outside a method (the way you normally
do
> in
>> Java), you''re actually creating an attribute of the _class_
(i.e., a
> static
>> attribute) rather than of an instance attribute.  You need to create
>> instance attributes inside a method.  Outside a method,
"self" is the
> Class
>> (!).
>
> I think you mean instance variables here, rather than attributes.
> Attributes are kind of second-order constructs layered on top of
> instance variables (i.e., when you do attr_reader and related methods,
> the attribute methods Ruby generates are implemented using instance
> variables).  But the instance variables themselves are not attributes;
> they can be used for different purposes.
>
> Maybe this makes it less of a ''gotcha'', in the sense that
instance
> variables can be understood incrementally from local variables (plus
> the "self" concept), and then attributes are built on top of
that.
>
>
> David
>
> --
> David A. Black (dblack@wobblini.net)
> Ruby Power and Light, LLC (http://www.rubypowerandlight.com)
>
> "Ruby for Rails" PDF now on sale!  http://www.manning.com/black
> Paper version coming in early May!
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--
David A. Black (dblack@wobblini.net)
Ruby Power and Light, LLC (http://www.rubypowerandlight.com)

"Ruby for Rails" PDF now on sale!  http://www.manning.com/black
Paper version coming in early May!