Norvig's minimal Lisp interpreter tutorial demystifies how code evaluates code

Peter Norvig published a tutorial on 21 June 2026 showing how to build a working Scheme interpreter—a program that reads and executes Lisp code—in under 100 lines of Python. The guide covers the three core steps: breaking text into tokens (lexing), arranging them into structure (parsing), and running that structure (evaluation). Norvig's compact approach uses dictionaries for variable storage and closures for functions, making the mechanics visible to engineers.