NUOO-Prolog

NUOO-Prolog is a simple object oriented extension to NU-Prolog, mostly hacked together by Lee Naish rather quicky. It works as a preprocessor. Check out the (brief) examples below for some of the syntax/features. One of the nice things about the system is that its "pure" in the sense it can easily be given clear declarative semantics. A prototype declarative debugger has been implemented. The down side is that objects can't have mutable state. The tech report gives more information on the language and implementation. The tech report describes a version implemented on top of Quintus Prolog. The version here has some improvements such as parameterised objects. I also have an implementation of further enhancements such as supporting separate compilation and various forms of multiple inheritance.

I have certainly found it of use for knowledge bases I have had to maintain. Examples include coordinating honours and other fourth year courses where there are students, thesis topics, supervisors etc, and coordinating the technical programme of the ICLP'97 conference (paper submissions, reviews etc).

Examples

The famous Tweety: tweety.op (preprocessed to become tweety.nl)
Objects with parameters: shape.op (preprocessed to become shape.nl)
A boring example from the paper: sample.op (preprocessed to become sample.nl)

Source code

Source code (gzipped tar file)
Source code (tar/gzipped file) of version with additional features such as multiple inheritance
To run it you will need a copy of NU-Prolog . Actually the code is so short (around 300 lines) and simple you should be able to port it to any Unix-based Prolog easily.

Lee