From: wsdngtmp@... (Sascha Doerdelmann)
Date: 2004-05-26T19:38:44+09:00
Subject: Re: defining condititions

Florian Weber <csshsh@structbench.com> wrote:
> my_set.rules = !name("orange") && hasProperty("color") && 
> (hasProperty("size") || hasProperty("weight"))

Apply the composite pattern, see
http://c2.com/cgi/wiki?CompositePattern
or
http://unicoi.kennesaw.edu/~jbamford/csis4650/uml/GoF_Patterns/composite.htm

Forget about the addComponent, removeComponent messages. You need a
different way to build composite rules. As in the pattern you need an
abstract class for all components. Call it AbstractRule and build
subclasses for composed rules and concrete rules. Implement messages
like "and", "or", etc. in AbstractRule, each of them should return a
composed rule. Depending on your implementation of the composed rules
you might overwrite these messages in composed rules.

Cheers
Sascha