code on Azrea Amis

Compiling Forsp Stacklessly

Mon, 21 Apr 2025 10:45:30 +0200

Forsp is fascinating language billed as a combination of Lisp and Forth. It’s stack based, but features easy idiomatic access to a local environment. This gives you the simplicity of Forth, but offers an “escape hatch” out of stack hell. Code that would require complicated stack/value shuffling in Forth can instead name the values and manipulate them in a way more natural to Lisp programmers. Forsp is also neither call by value nor call by name, but instead call by push value, though I’m not entirely clear on why this is interesting as I haven’t read the paper yet.

"Interesting" Clojure Macro Interaction

Sun, 15 Dec 2019 23:01:08 +0100

Clojure’s macro system is a little tricky to work with (at least for me), but it’s also quite powerful. Being able to rewrite the languages AST at compile time is really cool, and the fact that Clojure’s syntax is just the data structures that normal Clojure code operate on makes writing macros a breeze (at least compared to, say, Rust or Javascript). Clojure’s macro expansion works in dependable way: it keeps apply macros until there are no more macro calls in the code, then compiles the resulting code.

Monorepo Compromise

Sun, 03 Nov 2019 20:54:26 +0100

I have a modest proposal on repository organization. There are 2 primary archetypes, multiple repositories and the monorepo pattern. In multiple repositories, you have 1 project per repository, binaries requiring internal libraries, and use tools to ensure that you have all the necessary repositories downloaded and up to date (easy with most modern package managers). In a monorepo, all projects are stored directly in the monorepo, as part of a single codebase or project, and all internal dependencies are automatically managed.

Ironic Space Lisp Part 9

Thu, 29 Aug 2019 14:05:09 -0700

It’s been a long time since I last worked on ISL, mostly because I got distracted by other projects and languages: things like the flows project, or Clojure. Also, writing futures code in Rust is painful. Recently, async-await syntax got released on Rust nightly, which makes async code much easier to write. When I was last working on the project, I was working on a local variables feature. VM operations to allow storing and loading local variables linked to the frame stack, and later, support in the compiler.

Codegen Loader

Tue, 28 May 2019 17:04:04 -0700

In what is very likely an enormously bad idea, I have built a JVM classloader that can load dynamically load Java source files into memory. Why I’ve recently been going “Full Juxt”, using all of Juxt’s Clojure libraries, specifically juxt/aero for configuration, juxt/bidi for routing, juxt/yada for endpoint handling, weavejester/integrant for “building applications” (probably dependency injection), juxt/joplin for database migrations, and juxt/edge to tie it all together. All of Juxt’s libraries are relentlessly data focused, and use deps.

Pipeline Operators

Sat, 03 Nov 2018 19:28:01 -0700

Pipeline “operators” or “threading”1 constructs are interesting language constructs. They are an acknowledgement that functional code can be a little obtuse. They reorient (or rewrite) functional code so it looks more like a “dataflow”. Particularly of Lisps, but also of some other functional languages, execution moves from the inside of expressions to the outside in a way that’s not particularly natural feeling. It’s a real source of the difficulty people express when reading functional code.

Flows the Wrong Way, Part 2: The Right Way

Sat, 13 Oct 2018 12:36:21 -0700

Note in 2022: I’m in a very different state of mind compared to when I wrote this, and neither part represents my modern voice or style particularly well. I think it’s still a good story.

In my last post, I covered my first attempt to implement TCP streaming in Flow, a data flow library for Elixir. My first attempts involved a bunch of failed Unix sockets, and an attempt to implement a GenStage that failed for reasons I didn’t understand. I eventually settled on this:

Flows the Wrong Way: Streaming into Elixir

Wed, 10 Oct 2018 15:41:01 -0700

Note in 2022: I’m in a very different state of mind compared to when I wrote this, and neither part represents my modern voice or style particularly well. I think it’s still a good story. As part of a new and exciting project, I was faced with the task of ingesting a large amount of more or less homogeneous JSON data into a SQL database for an associate of mine to do some rudimentary business intelligence analysis on it.

Ironic Space Lisp Part 8

Thu, 20 Sep 2018 13:21:53 -0700

It’s been a while since I posted progress on ISL, and that is mostly my fault. Most of this time was spent making maintenance, like documentation, but also trying to get the self hosted interpreter working and self hosting. That was a challenge, and also my fault.

Ironic Space Lisp Part 7

Mon, 27 Aug 2018 15:56:11 -0700

Let’s talk about the VM internals. I’ve written a compiler for ISL, and implemented functions at the same time. This is not a mistake or an over-reach, rather a natural progression. To the VM, what is a function? The VM doesn’t have a strong concept of “functions”, or even of procedures. It has the Call and Return operations. These operations are the only way to manipulate the frame stack in a meaningful way: Call pushes an address to the frame stack, jumping to it, while Return pops an address, returning to the caller.

Ironic Space Lisp Part 6

Wed, 22 Aug 2018 01:56:10 -0700

Since last time, I did two things: switched from error_chain to failure, and refactored with the visitor pattern. They took about the same amount of time, and the refactor is much more interesting. I briefly touch on an issue I encountered with failure, but I’d rather discuss the refactor.

Ironic Space Lisp Part 5

Sun, 19 Aug 2018 20:44:24 -0700

Let’s talk about environmental bindings. I’m taking the unusual (I think) approach of sharing environment bindings code between the VM and the interpreter. Unfortunately, I wrote the environment code at the same time as the VM, and fit the code a little too closely to the requirements of the VM, and didn’t think enough about what the interpreter would require. In the process of writing the interpreter, I encountered a strong disconnect between the semantics that I wanted and the semantics I had.

Ironic Space Lisp Part 4

Sun, 12 Aug 2018 00:41:11 -0700

This update is all about parsing, and this ended up being really difficult. Not in a good way though. In my last post, I talked about using languages so difficult and alien that the difficulty clearly signified that there was something important you could learn from mastering them. I didn’t find this was the case during this phase of the project.

Ironic Space Lisp Part 3

Fri, 10 Aug 2018 17:09:28 -0700

Have you ever been working on a project and felt stupid and scared? Not in an anxious way, and not in an imposter syndrome way, but in a visceral way, like “I don’t really know what I’m doing, and I’m not sure I can do this.” Some languages are so complex and different that, although I know they’re full feature and Turing complete languages, I don’t know that I can even write whatever program I’m trying to make.

I hate Go, and I think it's really cool

Wed, 01 Aug 2018 14:02:48 -0700

My first impression of Go was, ironically, “kinda generic”. It’s an imperative language from Google inspired by Python (a little generic) and Java (reigning king of generic languages,) so some amount of “recognition” is due. Go wears its influences proudly on its sleeve, which is a little weird, because it’s not a particularly noteworthy heritage. The interesting thing (to me at least), is that this is all on purpose. Boring on purpose is an engineering feature, because excessively complicated languages are harder to work on, and produce harder to maintain code.

Ironic Space Lisp Part 2

Sun, 29 Jul 2018 10:59:40 -0700

Part 1

Part 2

Last time, the conceptual challenges of a the stack VM convinced me it was the wrong approach. In a normal recursive lisp interpreter, code is data, and you have a single evaluator function over every value. Follow along here.

Ironic Space Lisp Part 1

Sun, 29 Jul 2018 02:03:01 -0700

Part 1

Part 2

I recently had a new idea for a space programming game. The idea isn’t done, although the planning document is getting lengthy. Programming games need programming languages, and based on the game design, I had some pretty particular specifications for the language.

Hacking Turntable for Fun and Music

Fri, 25 Nov 2011 15:12:00 +0000

Previous Solutions Turntable is a collaborative DJ website that lets people play music to an online audience. Turntable, by default, doesn’t let you download the music you hear. If you hover over the track name in the UI, you can scrobble the track to Last.fm, find it in Spotify or Rdio, etc. Some people (myself included, but we’ll get to that later) wanted to download the files being played. So, a Greasemonkey script was created to automatically download songs as they were played on Turntable.