From: Benjohn Barnes <benjohn@...>
Date: 2006-07-26T06:31:39+09:00
Subject: Re: I'll have the duck!


On 25 Jul 2006, at 22:14, I wrongly wrote:
> it seemed a lot like prototype classes

I meant to say predicate classes. Sorry.

See:
	http://citeseer.ist.psu.edu/chambers93predicate.html

Abstract: Predicate classes are a new linguistic construct designed  
to complement normal classes in objectoriented languages. Like a  
normal class, a predicate class has a set of superclasses, methods,  
and instance variables. However, unlike a normal class, an object is  
automatically an instance of a predicate class whenever it satisfies  
a predicate expression associated with the predicate class. The  
predicate expression can test the value or state of the object, thus  
supporting a form of implicit...

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