Introducing Enums in a new piece

[prrao87]

I'm thinking about ways to introduce the concept of Enums using similar data to what exists in other pieces in this repo. Something along the lines of people and their metadata, so as to not deviate too far from the norm. There's tons of Enum examples online regarding video games or other such "creative" examples (wizards, mages and such), but I think the focus of this book should be a pragmatic approach, and sometimes, it's necessary to define boring Enums for boring problems 😀...

Just putting this down here to list out some ideas @sanders41.

[sanders41]

This is a good idea since enums are used all over the place in Rust and less common in Python. This could also be a place to introduce traits as a more advance topic after the initial introduction to enums. One thing that took me a minute to figure out was this difference:

In Python

class Color(Enum):
    RED = "red"
    BLUE = "blue"

print(Color.RED.value)

This doesn't work in Rust, instead you implement the Display trait

enum Color {
    Red,
    Blue,
}

impl fmt::Display for Color {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match self {
            Color::Red => write!(f, "red"),
            Color::Blue => write!(f, "blue"),
        }
    }
}

fn main() {
    println!("{}", Color::Red);
}

Before I learned about implementing this trait I thought it just wasn't possible to have the red, blue rather than Red, Blue in rust.