[Newbies] Concrete classes... multiple users

[David T. Lewis]

On Sat, Oct 27, 2007 at 09:51:52PM -0400, John Almberg wrote:
> Hi Ron,
> 
> In a nutshell, I have an application that needs to read Items from a  
> database.
> 
> I recently discovered that in Smalltalk classes are real objects.  
> This struck me as cool, so when I was deciding how to instantiate  
> these Items, I thought, hey I'll use the class object as a factory  
> (actually, I think it's more of an adapter pattern, but...)
> 

<snip>

> So, I think it was a case of falling in love with a cool feature, and  
> then mis-applying it, just because it was dying to be used.

On the contrary, it sounds to me like you approached the problem in
exactly the right way. You correctly observed that classes can serve
as factories, so there was no need to invent something new for that
purpose. You used that understanding to implement a simple solution
that worked well, and when you encounted a need to support additional
complexity, you refactored your system to do so. Well done.

One of the things that makes Smalltalk an enjoyable environment is
that it does not force you to completely understand a problem before
you get started solving it. You can start simply and move things around
later on as you improve your understanding and discover your mistakes.

> Hope this explains it... I'm afraid I don't always get the jargon  
> right, but that's why I'm a newbie, I guess!

If you like to think in terms of design patterns, "Smalltalk Best
Practice Patterns" by Kent Beck is a very useful guide.

Dave