So, as a follow-up to the original silly-formatting post, I spent some time trying to figure out just how bad the LALRPOP-based sillyfmt implementation was. It turns out that there’s really nice utilities for using the afl fuzzer with Rust, so I hooked that up with some pretty basic heuristics and let it run for a few seconds. Then, since it turned out to be really bad, I got nerd-sniped into setting up a different parser called tree-sitter that uses a more generic parsing algorithm. Unfortunately, that led to another rabbit-hole: tree-sitter is a C library,and while Rust/C interop is generally good, this is much less true when you involve the WebAssembly toolchain(s).

In my time at Dropbox, I found myself fairly often trying to quickly read through “traces”, which were essentially developer-formatted text logged from the Dropbox desktop client. The Dropbox client was originally written back before structured logging was common in industry, and in any case setting up structured logs can add a fair bit of overhead to the day-to-day debugging lifecycle.

After spending an inordinate amount of time opening complicated traces in vim and using the rudimentary formatting options available there, plus a bunch of manual labor, I eventually decided to save myself a lot of time by looking for a formatter that could automate the work away.