Rust patterns

Newtype Deref Pattern

---

You wrap a type (e.g., f64, i64) in a “newtype” (a single-field struct) and implement the Deref trait to delegate access to the inner value, to combine type-safety with ergonomic access:

• the wrapper distinguish the type
• users can access the inner value using the *my_type deref syntax

use std::ops::Deref;
 
pub struct Kilometers(pub f64);
 
impl Deref for Kilometers {
    type Target = f64;
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}