Object Lisp was a computer

Computer

A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...

 programming language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

, a dialect of the Lisp language. It was an object-oriented

Object-oriented programming

Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...

 extension for the Lisp dialect Lisp Machine Lisp

Lisp Machine Lisp

Lisp Machine Lisp is a dialect of the Lisp programming language, a direct descendant of Maclisp, and was initially developed in the mid to late 1970s as the systems programming language for the MIT Lisp machines. Lisp Machine Lisp was also the Lisp dialect with the most influence on the design of...

, designed by Lisp Machines

Lisp Machines

Lisp Machines, Inc. was a company formed in 1979 by Richard Greenblatt of MIT's Artificial Intelligence Laboratory to build Lisp machines. It was based in Cambridge, Massachusetts....

, Inc. Object Lisp was also an early example of prototype-based programming

Prototype-based programming

Prototype-based programming is a style of object-oriented programming in which classes are not present, and behavior reuse is performed via a process of cloning existing objects that serve as prototypes. This model can also be known as classless, prototype-oriented or instance-based programming...

.

It was seen as a competitor to other object-oriented extensions to Lisp at around the same time such as Flavors, in use by Symbolics

Symbolics

Symbolics refers to two companies: now-defunct computer manufacturer Symbolics, Inc., and a privately held company that acquired the assets of the former company and continues to sell and maintain the Open Genera Lisp system and the Macsyma computer algebra system.The symbolics.com domain was...

, Common Objects developed by Hewlett-Packard

Hewlett-Packard

Hewlett-Packard Company or HP is an American multinational information technology corporation headquartered in Palo Alto, California, USA that provides products, technologies, softwares, solutions and services to consumers, small- and medium-sized businesses and large enterprises, including...

, and CommonLoops

CommonLoops

CommonLoops is an early programming language which extended Common Lisp to include Object-oriented programming functionality and is a dynamic object system which differs from the OOP facilities found in static...

, in use by Xerox

Xerox

Xerox Corporation is an American multinational document management corporation that produced and sells a range of color and black-and-white printers, multifunction systems, photo copiers, digital production printing presses, and related consulting services and supplies...

.

Object Lisp was also used in early versions of Macintosh Common Lisp

Macintosh Common Lisp

Macintosh Common Lisp is an implementation and IDE for the Common Lisp programming language. Various versions of MCL run under Mac OS and Mac OS X....

. There, the user interface toolkit was written using Object Lisp.