Noções Básicas de Tratamento de Erros

fn find(ids: &[u32], target: u32) -> Option<usize> {
    ids.iter().position(|&id| id == target)
}

use std::fs;
 
fn read(path: &str) -> Result<String, std::io::Error> {
    fs::read_to_string(path)
}

fn main() {
    match read("Cargo.toml") {
        Ok(body) => println!("{body}"),
        Err(e) => eprintln!("{e}"),
    }
}

let n: u32 = "42".parse().expect("porta válida");

fn load() -> Result<String, std::io::Error> {
    let s = std::fs::read_to_string("config.toml")?;
    Ok(s)
}

fn first_user(names: &[&str]) -> Result<&str, &'static str> {
    names.first().ok_or("lista vazia")
}

let port: Option<u16> = Some("8080")
    .and_then(|s| s.parse().ok());

enum AppError { Io(std::io::Error), Parse(std::num::ParseIntError) }