> In fact, Swift treats enums as more than just types and lets you put methods directly on it

You can do the exact same thing in Rust:

  impl Coin {
      fn valueInCents(&self) -> u8 {
          match self {
              Self::Penny => 1,
              Self::Nickel => 5,
              Self::Dime => 10,
              Self::Quarter => 25,
          }
      }
  }