DESIGN AND IMPLEMENTATION OF A LISP INTERPRETER

Abstract

With Artificial Intelligence increasingly finding it's way into the commercial market place, a significant LISP market is starting to emerge. There is a growing comple-tition between vendors offering machines that run LISP, now regarded as a key to Artificial Intelligence. In this dissertation, design and implementation of a LISP interpreter on DEC-2050 system was taken up. The interpreter has been designed using Algol-60 as the host language. In addition to implementing five pure LISP func-tions, an effort has been made to implement certain additional features of advanced versions of LISP like LISP 1.5. These additional features of LISP include arithmetic functions, several predicates, conditional function, assignment func-tion and a provision for binding parameters. An extra feature of Garbage Collection has been also included in the interpreter to free the user from botheration of memory space limits. This collects the memory cells not being used by the program and adds them to the free memory area thus making them available for further use. This is particularly important in language like LISP because in it the data objects (lists) are created as well as destroyed during the course of execution of the program.