There are libraries like nom: https://lib.rs/crates/nom https://lib.rs/crates/nom or combine https://github.com/Marwes/combine/blob/master/examples/date.rs http

There are libraries like nom: https://lib.rs/crates/nom https://lib.rs/crates/nom or combine https://github.com/Marwes/combine/blob/master/examples/date.rs https://github.com/Marwes/combine/blob/master/examples/date.... that have more declarative-looking syntax. In TFA you intentionally get "raw Rust" to avoid syntax sugar obscuring what's going on.