CLiki: KR

Knowledge Representation is a highly flexible and dynamic prototype-based object system for Common Lisp. It is completely independent of CLOS and features among other things multiple inheritance and value propagation using constraints, much like Cells or COSI do, but in case of the latter there is actual source code around.

KR contains no implementation-specific code and should run on all major Common Lisp implementations. It is completely unmaintained, though.

Julian Stecklina has taken this out of the Garnet code, ASDF-ified it and fixed some non-standard code. If you are interested, contact him.

If you are looking for something to use in new code, you might consider David O'Toole's CLON which was inspired by KR.

Another ASDF-ized version of KR as it appears in Garnet 3.0 is available for cloning on GitHub.

KR manual is apparently available in PostScript version (alternately available as kr-manual.pdf).