A User Interface toolkit for Common Lisp.

It has a custom, prototype object system called KR with integrated constraints. Constraints are useful for modelling events and layout.

It is platform independant, but this is implemented poorly (it draws all the widgets itself, so applications look out of place).

It is WIMP oriented.

It provides an abstraction over input handling called interactors, which provide the basic interactive behaviors of the system with little code.

This page is linked from: Microkernel Debate