Properties of the OOF model (Gforth Manual)

This model combines object oriented programming with information hiding. It helps you writing large application, where scoping is necessary, because it provides class-oriented scoping.
Named objects, object pointers, and object arrays can be created, selector invocation uses the “object selector” syntax. Selector invocation to objects and/or selectors on the stack is a bit less convenient, but possible.
Selector invocation and instance variable usage of the active object is straightforward, since both make use of the active object.
Late binding is efficient and easy to use.
State-smart objects parse selectors. However, extensibility is provided using a (parsing) selector postpone and a selector '.
An implementation in Standard Forth is available.