Introduction

EusLisp is an integrated programming system for the research on intelligent robots based on Common Lisp and Object-Oriented programming. The principal subjects in the field of robotics research are sensory data processing, visual environment recognition, collision avoiding motion planning, and task planning. In either problem, three dimensional shape models of robots and environment play crucial roles. A motivation to the development of EusLisp was a demand for an extensible solid modeler that can easily be made use of from higher level symbolic processing system. Investigations into traditional solid modelers proved that the vital requirement for their implementation language was the list processing capability to represent and manage topology among model components. Numerical computation power was also important, but locality of geometric computation suggested the provision of vector/matrix functions as built-ins would greatly ease programming.

Thus the primary decision to build a solid modeler in a Lisp equipped with a geometric computation package was obtained. Although a solid modeler provides facilities to define shapes of 3D objects, to simulate their behaviors, and to display them graphically, its applications are limited until it is incorporated in robot modules mentioned above. These modules also need to be tightly interconnected to achieve fully integrated robot systems. EusLisp sought for the framework of this integration in object-oriented programming (OOP). While OOP promotes modular programming, it facilitates incremental extension of existing functions by using inheritance of classes. In fact, components in the solid modeler, such as bodies, faces, and edges, can orderly be inplemented by extending one of the most basic class coordinates. These components may have further subclasses to provide individual functions for particular robot applications.

Based upon these considerations, EusLisp has been developped as an object-oriented Lisp which implements an extensible solid modeler[#!Eus7!#]. Other features include intertask communication needed for the cooperative task coordination, graphics facilities on X-window for visual user interface, and foreign language interface to support mixed language programming.

In the implementation of the language, two performance-effective techniques were invented in type discrimination and memory management [#!Eus4!#,#!Eus5!#,#!Eus6!#]. The new type discrimination method guarantees constant-time discrimination between types in tree structured hiearchy without regard to the depth of trees. Heap memory is managed in Fibonacci buddy method, which improves memory efficiency without sacrificing runtime or garbage-collection performance.

This reference manual describes EusLisp version 7.27 in two parts, EusLisp Basics and EusLisp Extensions. The first part describes Common Lisp features and object-oriented programming. Since a number of literatures are available on both topics, the first part is rather indifferent except EusLisp's specific features as described in Interprocess Communication and Network, Toplevel Interaction, Disk Save, etc. Beginners of EusLisp are advised to get familiar with Common Lisp and object oriented programming in other ways [#!CLtL!#,#!CLOS:Keene!#]. The second part deals with features more related with robot applications, such as Geometric Modelling, Image Processing, Manipulator Model and so on. Unfortunately, the descriptions in this part may become incomplete or inaccurate because of EusLisp's rapid evolution. The update information is available via euslisp mailing list as mentioned in section 1.6.