Carnegie Mellon University
PORK Object System Programmers' Guide

Ora Lassila
tech. report CMU-RI-TR-95-12, Robotics Institute, Carnegie Mellon University, April, 1995

  • Adobe portable document format (pdf) (254KB)
Copyright notice: This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.

PORK is an object system which brings a conventional object-oriented language closer to the requirements of frame-based programming. It only provides a very limited set of features (on top of the base object system itself), and aims to achieve seamless integration with conventional programming. PORK is implemented as a portable metalevel extension of the Common Lisp Object System (CLOS). It extends CLOS by adding the following concepts:

* Named objects. These simplify debugging and linked frame model construction. Collections of named objects (called "namespaces") can also be used as a low-level implementation vehicle for knowledge bases.

* References to nonexisting named objects. Programs can manipulate objects that have not yet been created. This greatly simplifies definition of complex linked frame models with circular references.

* Slots with multiple values, and a mechanism for defining an access interface.

* Automatic updating of inverse slots.

Sponsor: ARPA, NASA
Grant ID: F30602-90-C-0019, F30602-91-C-0014, NCC 2-531
Associated Center(s) / Consortia: Center for Integrated Manfacturing Decision Systems
Associated Lab(s) / Group(s): Intelligent Coordination and Logistics Laboratory
Number of pages: 59

Text Reference
Ora Lassila, "PORK Object System Programmers' Guide," tech. report CMU-RI-TR-95-12, Robotics Institute, Carnegie Mellon University, April, 1995

BibTeX Reference
   author = "Ora Lassila",
   title = "PORK Object System Programmers' Guide",
   booktitle = "",
   institution = "Robotics Institute",
   month = "April",
   year = "1995",
   number= "CMU-RI-TR-95-12",
   address= "Pittsburgh, PA",