[plt-scheme] Equivalent of abstract classes?

(define-syntax-rule 
  (define/abstract foo) 
  ;; --> 
  (define/public (foo . x) (error 'foo "is an abstract method in an abstract class"))

The real question is why one would want one. 



On Dec 5, 2009, at 6:24 PM, Todd O'Bryan wrote:

> Is there the equivalent of Java's abstract classes  (i.e., interfaces
> with some default implementations) in PLT's class system?
> 
> Todd
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