Simon Dobson (Posts about applications)

A Lisp interpreter implemented in Conway's Game of Life

Simon Dobson — Fri, 22 May 2026 11:47:12 GMT

A Lisp interpreter implemented in Conway's Game of Life

A Lisp Interpreter Implemented in Conway’s Game of Life

I include this as an application rather than an implementation technique because … well … it's far more interesting as an example of cellular automata (CAs) than as a Lisp.

Having said that, there's something utterly compelling in watching a CA run something this complicated. It basically implements a Lisp machine core, and watching it execute is rather like watching a real chip in action (even though the mechanisms are completely different). You can see memory being accessed. Its implementation includes lexical closures, enough to build a simple object system.

The implementation uses the VarLife system as an abstraction layer over the "raw" Conway rules. The compiled programs can be run on the Golly CA emulator.

Common Lisp screenshots

Simon Dobson — Fri, 22 May 2026 11:46:17 GMT

Common Lisp screenshots

https://www.lisp-screenshots.org/

A collection of links to Common Lisp applications, including utilities, games, and full-blown science packages and web applications. Most have links to the applications' home pages.

Loving Common Lisp, or the savvy programmer's secret weapon

Simon Dobson — Tue, 02 Apr 2024 15:57:38 GMT

Loving Common Lisp, or the savvy programmer's secret weapon

Mark Watson. Loving Common Lisp, or the Savvy Programmer’s Secret Weapon. Leanpub. 2023.

While pitched as a way of sharing the author's enthusiasm for Lisp (which really shines through), this book is really a deep demonstration in using Lisp in modern applications – from web APIs and the semantic web to deep learning, large language models, and chatbots.

In some ways, like many other Lisp books, it's really two books in one. The first chapters are introductory – and to be perfectly honest could be dispensed with, as they're inadequate as a proper introduction and there are far better introductions out there. The later chapters focus on applications, and provide the real value. One could criticise them as often tying-together tools in other languages, with the Lisp code basically being glue; but that's a very effective way of leveraging all the code and services out there, and is an important technique for Lisp programmers too.

Lisp in space

Simon Dobson — Tue, 02 Apr 2024 15:32:56 GMT

Lisp in space

Lisp in space (podcast, 38 minutes)

An interview on the Corecursive podcast with Ron Garret.

In 1988 (when, for context, I was in the second year of my BSc) Garret started working on autonomous navigation software for Sojourner, NASA's first Mars rover, which flew in 1997. He used Lisp to do planning, essentially developing an entire domain-specific language for autonomous vehicles. The project was never flown, as NASA opted for a far less ambitious approach to driving to rovers – a decision that Garret now considers to have been the correct one.

But that isn't the end of the story, because Garret then went on to develop an autonomous Remote Agent controller for the Deep Space 1 technology demonstration mission that performed asteroid and comet fly-bys. Without spoiling to story, the spacecraft flies with a full Lisp system onboard, and Garret gets to interact with its REPL at a distance of 30 light-minutes via the Deep Space Network – surely the longest latency of any REPL session ever!

It's an fascinating insight into both the potentials of Lisp and the political difficulties that using a non-standard development language can engender.

UPDATE 2024-05-16: Ron also wrote a short essay about his experiences.

How Lisp is designing nanotechnology

Simon Dobson — Fri, 15 Mar 2024 19:19:15 GMT

How Lisp is designing nanotechnology

How Lisp is designing nanotechnology (video, 52 minutes).

An interview on the Developer Voices podcast with Prof Christian Schafmeister on designing enzymes using a custom dialect of Lisp to control computational chemistry libraries.

He initially started from an idea based on CAD applications (written in Smalltalk), but rapidly realised there were too many possible components and combinations to work with graphically and so started treating it as a language-design problem – and designed a custom Lisp based on ECL. Lisp provides simplicity and efficiency, as well as being a "forever" language in which software keeps working over the long term.

Lisp for the web

Simon Dobson — Sun, 10 Mar 2024 10:28:45 GMT

Lisp for the web

Adam Tornhill. Lisp for the Web. Leanpub. 2015.

A short, practical guide to build a dynamic web site entirely using Common Lisp. Makes extensive use of several libraries, including the intriguingly-named hunchentoot web server (named after a never-staged musical written by Frank Zappa), the CL-WHO HTML generator, and – perhaps most interesting – the Parenscript Lisp to Javascript compiler.

One gain from using Lisp is the ability to wrap-up standard constructions like page templates as macros. Other than this, it's hard to assess whether the gains are all that significant. One interesting point is that the whole development occurs in Lisp, so there's no cognitive dissonance between writing the back-end and the front-end: essentially the same argument for using node.js as a back-end framework. While Parenscript isn't a fully-featured Lisp-in-the-browser it again can benefit from macros and other features. There's a throwaway comment about linking it to jQuery, although that isn't demonstrated in practice: it feels intriguing, though, especially if there's a way to represent jQuery functionality idiomatically in Lisp.