A New Smalltalk Kernel Allowing Both Explicit and Implicit Metaclass Programming

NeoClassTalk, a new class/metaclass kernel for Smalltalk that is based on explicit metaclasses. 

In this system, end-users still deal with implicit metaclasses, but the full expressiveness of explicit metaclasses is provided to language designers. Dealing with explicit metaclass programming, NeoClassTalk proposes a new framework allowing dynamic composition of class properties such as MessageTracing, pre/post conditions, and Singleton instances.
-----
References:

An explicit metaclass kernel in Smalltalk, named NeoClassTalk [2] (a new version of Classtalk [1]). The complete implementation of this system is described in [3]. 
 
[1] JeanPierreBriot and PierreCointe. Programming with Explicit Metaclasses in Smalltalk-80. 
 In OOPSLA'89 Proceedings, pages 419-431. ACM Sigplan Notices, October 1989. 

[2] FredRivard. A New Smalltalk Kernel Allowing Both Explicit and Implicit Metaclass Programming. 
 In OOPSLA'96 Wokshop : "Extending the Smalltalk Language", San Jose, California, October 1996. 

[3] FredRivard. Evolution du comportement des objets dans les langages `a classes r'eflexifs. PhD thesis, Ecole des Mines de Nantes, France, June 1997.