[xymostech]

This was such a wonderful read! I've been getting into Rust recently, and the sections on dealing with challenges that are specific to Rust were particularly useful. The way they created a new trait to turn `Fn(&str) -> Result<(&str, T), &str>` into `Parser<T>` was insightful, and the discussion of how they dealt with the growing sizes of types was something that I can imagine myself running into in the future.

Most importantly though, when they started writing `and_then`, my eyes lit up and I said "It's a Monad!" I think this is the first time I've really identified a Monad out in the wild, so I enjoyed that immensely.