on joue avec des results

main.rs

use rand::prelude::*;

#[derive(Debug)]
struct JaiPasDentierError {}

#[derive(Debug)]
struct JaiPasReussiError {}

#[derive(Debug)]
enum MyError {
    PasDentier(JaiPasDentierError),
    PasReussi(JaiPasReussiError),
}

impl From<JaiPasDentierError> for MyError {
    fn from(e: JaiPasDentierError) -> Self {
        Self::PasDentier(e)
    }
}
impl From<JaiPasReussiError> for MyError {
    fn from(e: JaiPasReussiError) -> Self {
        Self::PasReussi(e)
    }
}

fn donne_moi_un_entier_stp() -> Result<i32, JaiPasDentierError> {
    if rand::random() {
        Ok(1234)
    } else {
        Err(JaiPasDentierError {})
    }
}

fn multiplie_le_par_deux(i: i32) -> i32 {
    i * 2
}

fn tente_un_truc_avec(i: i32) -> Result<i32, JaiPasReussiError> {
    if rand::random() {
        Ok(i * 3)
    } else {
        Err(JaiPasReussiError {})
    }
}
fn main() -> Result<(), MyError> {
    let entier = donne_moi_un_entier_stp()?;
    let fois_deux = multiplie_le_par_deux(entier);
    let reussi = tente_un_truc_avec(fois_deux)?;
    println!("{}", reussi);
    Ok(())
}