The Evolution of Lisp

Lisp is the world’s greatest programming language—or so its proponents think. The
structure of Lisp makes it easy to extend the language or even to implement entirely new
dialects without starting from scratch. Overall, the evolution of Lisp has been guided
more by institutional rivalry, one-upsmanship, and the glee born of technical cleverness
that is characteristic of the “hacker culture” than by sober assessments of technical
requirements. Nevertheless this process has eventually produced both an industrialstrength
programming language, messy but powerful, and a technically pure dialect,
small but powerful, that is suitable for use by programming-language theoreticians.
We pick up where McCarthy’s paper in the first HOPL conference left off. We trace
the development chronologically from the era of the PDP-6, through the heyday of
Interlisp and MacLisp, past the ascension and decline of special purpose Lisp machines,
to the present era of standardization activities. We then examine the technical evolution
of a few representative language features, including both some notable successes and
some notable failures, that illuminate design issues that distinguish Lisp from other
programming languages. We also discuss the use of Lisp as a laboratory for designing
other programming languages. We conclude with some reflections on the forces that
have driven the evolution of Lisp.