Onyx provides basic mechanisms for programming in an object-oriented style. The class and instance types, additional attributes (callable, invokable, and fetchable), a set of operators, and vclass, provide all the necessary functionality. The object-oriented programming support can be summarized by the following feature list:
Very little policy is built into the operators that implement the foundation for object-oriented programming support. See Section 2.12.1 for details on the policies that are set by vclass, which is provided as a default base class.