/
germanubis
/
clap
Обзор
Документация
Войти
/
germanubis
/
clap
Код
Запросы
0
Задачи
Вики
Пакеты
0
Релизы
0
Аналитика
Безопасность
master
examples/tutorial_builder/04_01_enum.rs
66 строк
2 KB
Ed Page
chore: Update from template
14 май 2024, 20:27
14 май 2024, 20:27
800d7cb
Код
Авторство
О чём код?
use clap::{arg, builder::PossibleValue, command, value_parser, ValueEnum}; #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord)] enum Mode { Fast, Slow, } // Can also be derived with feature flag `derive` impl ValueEnum for Mode { fn value_variants<'a>() -> &'a [Self] { &[Mode::Fast, Mode::Slow] } fn to_possible_value(&self) -> Option<PossibleValue> { Some(match self { Mode::Fast => PossibleValue::new("fast").help("Run swiftly"), Mode::Slow => PossibleValue::new("slow").help("Crawl slowly but steadily"), }) } } impl std::fmt::Display for Mode { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { self.to_possible_value() .expect("no values are skipped") .get_name() .fmt(f) } } impl std::str::FromStr for Mode { type Err = String; fn from_str(s: &str) -> Result<Self, Self::Err> { for variant in Self::value_variants() { if variant.to_possible_value().unwrap().matches(s, false) { return Ok(*variant); } } Err(format!("invalid variant: {s}")) } } fn main() { let matches = command!() // requires `cargo` feature .arg( arg!(<MODE>) .help("What mode to run the program in") .value_parser(value_parser!(Mode)), ) .get_matches(); // Note, it's safe to call unwrap() because the arg is required match matches .get_one::<Mode>("MODE") .expect("'MODE' is required and parsing will fail if its missing") { Mode::Fast => { println!("Hare"); } Mode::Slow => { println!("Tortoise"); } } }