Wikipedia
XOTcl
XOTcl is an object-oriented extension for the Tool Command Language created by Gustaf Neumann and Uwe Zdun. It is a derivative of MIT OTcl. XOTcl is based on a dynamic object system with metaclasses which as influenced by CLOS. Class and method definitions are completely dynamic. XOTcl provides language support for design patterns via filters and decorator mixins.