Loom or LOOM is a knowledge representation

Knowledge representation

Knowledge representation is an area of artificial intelligence research aimed at representing knowledge in symbols to facilitate inferencing from those knowledge elements, creating new elements of knowledge...

 language developed by researchers in the Artificial Intelligence

Artificial intelligence

Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

 research group at the University of Southern California

University of Southern California

The University of Southern California is a private, not-for-profit, nonsectarian, research university located in Los Angeles, California, United States. USC was founded in 1880, making it California's oldest private research university...

's Information Sciences Institute

Information Sciences Institute

The Information Sciences Institute is a research and development unit of the University of Southern California's Viterbi School of Engineering which focuses on computer and communications technology and information processing...

. The Loom project's goal is the development and fielding of advanced tools for knowledge representation and reasoning in Artificial Intelligence.

Loom is a language and environment for constructing intelligent applications. At its heart is a knowledge representation system that is used to provide deductive

Deductive reasoning

Deductive reasoning, also called deductive logic, is reasoning which constructs or evaluates deductive arguments. Deductive arguments are attempts to show that a conclusion necessarily follows from a set of premises or hypothesis...

 support for the declarative portion of the Loom language. Declarative knowledge in Loom consists of definitions, rules, facts, and default rules. A deductive engine called a classifier utilizes forward-chaining, semantic unification and object-oriented truth maintenance technologies in order to compile the declarative knowledge into a network designed to efficiently support on-line deductive query processing.

The Loom system implements a logic-based pattern matcher that drives a production rule

Production rule

Production rule may refer to:*For production rules used in business rule engines, cognitive modeling and artificial intelligence, see production system*For production rules that expand nodes in formal grammars, see formal grammar-See also:...

 facility and a pattern-directed method dispatching facility that supports the definition of object-oriented methods. The high degree of integration between Loom's declarative and procedural components permits programmers to utilize logic programming, production rule, and object-oriented programming paradigms in a single application. Loom can also be used as a deductive layer that overlays an ordinary CLOS

CLOS

The Common Lisp Object System is the facility for object-oriented programming which is part of ANSI Common Lisp. CLOS is a powerful dynamic object system which differs radically from the OOP facilities found in more static languages such as C++ or Java. CLOS was inspired by earlier Lisp object...

(Common Lisp Object System) network. In this mode, users can obtain many of the benefits of using Loom without impacting the function or performance of their CLOS-based applications.

Loom has recently been succeeded by PowerLoom http://www.isi.edu/isd/LOOM/PowerLoom/index.html