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use std::{error, fmt, str::FromStr};
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum Key {
Id,
Type,
Number,
Values,
}
impl AsRef<str> for Key {
fn as_ref(&self) -> &str {
match self {
Self::Id => "ID",
Self::Type => "Type",
Self::Number => "Number",
Self::Values => "Values",
}
}
}
impl fmt::Display for Key {
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,
}
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 => f.write_str("invalid input"),
}
}
}
impl FromStr for Key {
type Err = ParseError;
fn from_str(s: &str) -> Result<Self, Self::Err> {
match s {
"" => Err(ParseError::Empty),
"ID" => Ok(Self::Id),
"Type" => Ok(Self::Type),
"Number" => Ok(Self::Number),
"Values" => Ok(Self::Values),
_ => Err(ParseError::Invalid),
}
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_fmt() {
assert_eq!(Key::Id.to_string(), "ID");
assert_eq!(Key::Type.to_string(), "Type");
assert_eq!(Key::Number.to_string(), "Number");
assert_eq!(Key::Values.to_string(), "Values");
}
#[test]
fn test_from_str() {
assert_eq!("ID".parse(), Ok(Key::Id));
assert_eq!("Type".parse(), Ok(Key::Type));
assert_eq!("Number".parse(), Ok(Key::Number));
assert_eq!("Values".parse(), Ok(Key::Values));
assert_eq!("".parse::<Key>(), Err(ParseError::Empty));
assert_eq!("Noodles".parse::<Key>(), Err(ParseError::Invalid));
}
}