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use std::{error, fmt, str::FromStr};
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum Phase {
Zero,
One,
Two,
}
impl AsRef<str> for Phase {
fn as_ref(&self) -> &str {
match self {
Self::Zero => "0",
Self::One => "1",
Self::Two => "2",
}
}
}
impl fmt::Display for Phase {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.write_str(self.as_ref())
}
}
#[derive(Clone, Debug, Eq, PartialEq)]
pub enum ParseError {
Empty,
Invalid(String),
}
impl error::Error for ParseError {}
impl fmt::Display for ParseError {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
match self {
Self::Empty => f.write_str("empty input"),
Self::Invalid(s) => write!(f, "expected {{0, 1, 2}}, got {}", s),
}
}
}
impl FromStr for Phase {
type Err = ParseError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"" => Err(ParseError::Empty),
"0" => Ok(Self::Zero),
"1" => Ok(Self::One),
"2" => Ok(Self::Two),
_ => Err(ParseError::Invalid(s.into())),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_fmt() {
assert_eq!(Phase::Zero.to_string(), "0");
assert_eq!(Phase::One.to_string(), "1");
assert_eq!(Phase::Two.to_string(), "2");
}
#[test]
fn test_from_str() -> Result<(), ParseError> {
assert_eq!("0".parse::<Phase>()?, Phase::Zero);
assert_eq!("1".parse::<Phase>()?, Phase::One);
assert_eq!("2".parse::<Phase>()?, Phase::Two);
assert_eq!("".parse::<Phase>(), Err(ParseError::Empty));
assert_eq!(
"3".parse::<Phase>(),
Err(ParseError::Invalid(String::from("3")))
);
Ok(())
}
}