Tiddlylisp is a toy Lisp interpreter, written in Python, and intended to accompany the essay Lisp as the Maxwell's equations of software.

The repository contains the following files:

tiddlylisp.py: A simple interpreter for a subset of Lisp. Tiddlylisp is adapted from and closely based on Peter Norvig's lispy interpreter.

sqrt.tl: An example tiddlylisp program, for computing square roots. Adapted from an example in the book The Structure and Interpretation of Computer Programs, by Harold Abelson and Gerald Jay Sussman with Julie Sussmann.

eval.tl: A tiddylisp program defining a function eval which can evaluate any Lisp expression, albeit, for an even smaller subset of Lisp than tiddlylisp. Based on the LISP 1.5 Programmer's Manual and the essay The Roots of Lisp (postscript) by Paul Graham.

See the essay for more details.

Notifications of bugs (and bug fixes) are welcome, but I am not adding new features to tiddlylisp, as its main purpose is as a complement to the essay.

Note added (June 3, 2023): Switched to Python 3.