This is a page where I link code that I have written that is publicly available. Most of my professional work has been proprietary, and I have not been much of a hobbyist programmer over my career (though I’m trying to change that), so unfortunately most of my code doesn’t make it on here, but there is still some!

My GitHub is jhartzell42.

There is also code published on various articles on this blog. Any code on this blog is covered under the MIT license.

Rust#

• holdem_rs (hobby, 2024): Some basic Texas Hold-Em (poker) code, we’ll see what happens with it.
• prefix-range (hobby, 2023): Thank you Arvid Norlander for publishing my code from this blog post as a crate.
• serde-dbus (professional, 2021-2022): This is a serialization format for serde for the DBus messaging protocol’s marshalling format. It was necessary due to an issue adapting the more common zvariant to my employer’s specific needs. It currently only supports DBus messages formatted in a “loosely typed” manner (with signature a{sv}) rather than the strongly typed manner more commonly used with DBus, but this suited the needs we had.
• Pull requests accepted on open source projects:
  • rustls support for querying by IP address
  • cargo-bitbake reproducible mode
  • zbus can be used without zvariant
  • crossterm can be built without Windows deps in application Cargo.lock

C#

• ledger-app-tezos (professional, mostly 2018): Although I am not personally a cryptocurrency enthusiast, during my time working for Obsidian Systems, it was part of my job to implement this app to support Tezos on the Ledger. Though it was a group project, I was the primary original author. The original target platform, the Ledger Nano S, had only 4K of RAM. I understand it has changed a lot since I originally worked on it.
• compass (hobby, 2009-2010): This was a hobby project with a friend in college, and it is a bytecode interpreter for a Smalltalk-like language in C, combined with a compiler in Python and an “assembler” for the bytecode language also in C.

Haskell#

• reflex-chess (hobby, mostly 2019): This is a sample game written using Reflex. It only allows playing against another local user. It has also been worked into the official reflex-examples repo.
• reflex-word-tiles (hobby, 2022): A Wordle clone. Work in progress.
• Pull requests accepted on open source projects:
  • reflex-dom bugfix
  • reflex-examples add chess