Implementing LISP in a high‐level language

The problems of producing an efficient but robust implementation of a high‐level language by building on existing compilers are discussed with reference to a LISP system consisting of an interpreter, a compiler and a large collection of support routines. In retrospect it can be seen that almost all of the major difficulties encountered were facets of a general problem concerned with the global control of the use of store. The garbage collector, originally intended solely to manage the LISP heap, extends its scope to simplify the solution of many of these problems.