Primarily running with Rust, maybe I will write some Haskell or Python solutions for fun.
Requires rust nightly (for day 6).
Run ./compare.sh to compare the outputs of the Rust and Python solutions.
(Stopped writing Python solutions, so only up to a day 13.)
$ cargo run <day>
$ cabal run aoc2020 <day>
$ python src/day<day>.py