Chiming in - I've found the Pattern type in Unison[0] to be very nice to use. When you're just using the built-in patterns, it is similar to verbose regex. The real power of them is that it's easy to define, name, and re-use sub-patterns. I think it's similar to parser combinators in this way, like nom from rust[1].

[0] https://share.unison-lang.org/@unison/website/code/main/late...

[1] https://docs.rs/nom/latest/nom/