The best ChatGPT that $100 can buy.

Git extensions to provide high-level repository operations for Vincent Driessen's branching model.

The power of Claude Code / GeminiCLI / CodexCLI + [Gemini / OpenAI / OpenRouter / Azure / Grok / Ollama / Custom Model / All Of The Above] working as one.

Double-entry accounting system with a command-line reporting interface

The JSON Schema specification

The math library of Lean 4

A self-hosting Scheme to WebAssembly compiler

My .emacs.el file and other personal Emacs goodies

Web server written in Common Lisp

Scientific computing in Lean 4

Aquamacs Emacs

plasTeX plugin to build formalization blueprints.

The Lean Computer Science Library (CSLib)

A minimal development of SSA theory

Lean Theorem Prover MCP

A Lean 4 library for configuring Command Line Interfaces and parsing command line arguments.

JSON Schema in every programming language

Hosts the website for mathlib and other Lean community infrastructure.

Racket DSL for generating parsers from BNF grammars [moved to https://git.matthewbutterick.com/mbutterick/brag]

A distribution of Aquamacs, SBCL and SLIME which offers the simplest way to run Common Lisp on Mac OS X

Faceted execution in Racket

Tools for exploring logic through Lorenzen dialogue games.

RFC6265 cookie libraries for Racket

Chez Scheme

Theory development with TPTP

Breaking up mizar articles into bits and computing relations among them.

Licensing for the Mizar Mathematical Library

MSc Thesis: Evidentialist Logic