For the last few weeks, I have been working on an app idea that I had been thinking about for a long time. Ever since I started going on multi-day hikes, I have been looking for a good solution to plan hikes in advance and navigate while doing them.

A while back, I decided to implement a self-hosted Forth interpreter/compiler for the ZI-28, my Z80-based computer. The previous version of the software consisted of a simple operating system written in assembly, with applications and games written in C. There were some things I was unhappy about. Writing the OS in assembly was slow and error-prone. Writing the applications in C was much faster and easier in comparison, but it required the use of z88dk, a big software suite that was difficult to set up and went against my goal of the whole project.

LLL is my first proper attempt at designing and implementing a useful and modern programming language. To give me some direction, I leaned heavily on the excellent Crafting Interpreters book by Robert Nystrom. I did however make some of my own choices when it came to language design and implementation. I also chose to implement the interpreter in Rust, which presented me with some additional challenges due to my limited knowledge of that language, but also allowed me to learn a lot of new things about it.