#![forbid(unsafe_code)]
use core::fmt::{Debug, Display, Formatter};
pub enum OptionAbc<A, B, C> {
A(A),
B(B),
C(C),
}
impl<T> OptionAbc<T, T, T> {
pub fn take(self) -> T {
match self {
OptionAbc::A(value) | OptionAbc::B(value) | OptionAbc::C(value) => value,
}
}
}
impl<A, B, C> OptionAbc<A, B, C> {
pub fn as_ref(&self) -> OptionAbc<&A, &B, &C> {
match self {
OptionAbc::A(value) => OptionAbc::A(value),
OptionAbc::B(value) => OptionAbc::B(value),
OptionAbc::C(value) => OptionAbc::C(value),
}
}
pub fn a(&self) -> Option<&A> {
match self {
OptionAbc::A(value) => Some(value),
_ => None,
}
}
pub fn b(&self) -> Option<&B> {
match self {
OptionAbc::B(value) => Some(value),
_ => None,
}
}
pub fn c(&self) -> Option<&C> {
match self {
OptionAbc::C(value) => Some(value),
_ => None,
}
}
}
impl<A: Debug, B: Debug, C: Debug> OptionAbc<A, B, C> {
pub fn unwrap_a(self) -> A {
match self {
OptionAbc::A(value) => value,
_ => panic!("expected OptionABC::A(_) but found {:?}", self),
}
}
pub fn unwrap_b(self) -> B {
match self {
OptionAbc::B(value) => value,
_ => panic!("expected OptionABC::B(_) but found {:?}", self),
}
}
pub fn unwrap_c(self) -> C {
match self {
OptionAbc::C(value) => value,
_ => panic!("expected OptionABC::C(_) but found {:?}", self),
}
}
}
impl<A: Clone, B: Clone, C: Clone> Clone for OptionAbc<A, B, C> {
fn clone(&self) -> Self {
match self {
OptionAbc::A(value) => OptionAbc::A(value.clone()),
OptionAbc::B(value) => OptionAbc::B(value.clone()),
OptionAbc::C(value) => OptionAbc::C(value.clone()),
}
}
}
impl<A: Debug, B: Debug, C: Debug> Debug for OptionAbc<A, B, C> {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
match self {
OptionAbc::A(value) => write!(f, "OptionABC::A({:?})", value),
OptionAbc::B(value) => write!(f, "OptionABC::B({:?})", value),
OptionAbc::C(value) => write!(f, "OptionABC::C({:?})", value),
}
}
}
impl<A: Display, B: Display, C: Display> Display for OptionAbc<A, B, C> {
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
match self {
OptionAbc::A(value) => write!(f, "{}", value),
OptionAbc::B(value) => write!(f, "{}", value),
OptionAbc::C(value) => write!(f, "{}", value),
}
}
}
impl<A: PartialEq, B: PartialEq, C: PartialEq> PartialEq for OptionAbc<A, B, C> {
fn eq(&self, other: &Self) -> bool {
match (self, other) {
(OptionAbc::A(value), OptionAbc::A(other)) if value == other => true,
(OptionAbc::B(value), OptionAbc::B(other)) if value == other => true,
(OptionAbc::C(value), OptionAbc::C(other)) if value == other => true,
_ => false,
}
}
}
impl<A: PartialEq, B: PartialEq, C: PartialEq> Eq for OptionAbc<A, B, C> {}
#[cfg(test)]
mod tests {
use super::*;
#[allow(clippy::type_complexity)]
fn test_values() -> (
OptionAbc<bool, u8, &'static str>,
OptionAbc<bool, u8, &'static str>,
OptionAbc<bool, u8, &'static str>,
) {
(OptionAbc::A(true), OptionAbc::B(42), OptionAbc::C("s1"))
}
#[test]
fn test_as_ref() {
let (a, b, c) = test_values();
let _: OptionAbc<&bool, &u8, &&'static str> = a.as_ref();
let _: &u8 = b.as_ref().unwrap_b();
let _: &&'static str = c.as_ref().unwrap_c();
assert!(*(a.as_ref().unwrap_a()));
assert_eq!(42_u8, *(b.as_ref().unwrap_b()));
assert_eq!("s1", *(c.as_ref().unwrap_c()));
}
#[test]
fn test_accessors() {
let (a, b, c) = test_values();
assert!(*(a.a().unwrap()));
assert_eq!(None, a.b());
assert_eq!(None, a.c());
assert_eq!(None, b.a());
assert_eq!(42_u8, *(b.b().unwrap()));
assert_eq!(None, b.c());
assert_eq!(None, c.a());
assert_eq!(None, c.b());
assert_eq!("s1", *(c.c().unwrap()));
}
#[test]
fn test_debug() {
let (a, b, c) = test_values();
assert_eq!("OptionABC::A(true)", format!("{:?}", a));
assert_eq!("OptionABC::B(42)", format!("{:?}", b));
assert_eq!("OptionABC::C(\"s1\")", format!("{:?}", c));
}
#[test]
fn test_display() {
let (a, b, c) = test_values();
assert_eq!("true", format!("{}", a));
assert_eq!("42", format!("{}", b));
assert_eq!("s1", format!("{}", c));
}
#[test]
fn test_eq() {
let (a, b, c) = test_values();
assert_eq!(OptionAbc::A(true), a);
assert_ne!(OptionAbc::A(false), a);
assert_eq!(OptionAbc::B(42_u8), b);
assert_ne!(OptionAbc::B(2_u8), b);
assert_eq!(OptionAbc::C("s1"), c);
assert_ne!(OptionAbc::C("other"), c);
assert_ne!(a, b);
assert_ne!(a, c);
assert_ne!(b, c);
}
#[test]
fn test_unwrap() {
let (a, b, c) = test_values();
let a_clone = a.clone();
assert!(a_clone.unwrap_a());
let a_clone = a.clone();
assert_eq!(
"expected OptionABC::B(_) but found OptionABC::A(true)",
std::panic::catch_unwind(|| a_clone.unwrap_b())
.unwrap_err()
.downcast::<String>()
.unwrap()
.as_str()
);
let a_clone = a.clone();
assert_eq!(
"expected OptionABC::C(_) but found OptionABC::A(true)",
std::panic::catch_unwind(|| a_clone.unwrap_c())
.unwrap_err()
.downcast::<String>()
.unwrap()
.as_str()
);
let b_clone = b.clone();
assert_eq!(
"expected OptionABC::A(_) but found OptionABC::B(42)",
std::panic::catch_unwind(|| b_clone.unwrap_a())
.unwrap_err()
.downcast::<String>()
.unwrap()
.as_str()
);
let b_clone = b.clone();
assert_eq!(42_u8, b_clone.unwrap_b());
let b_clone = b.clone();
std::panic::catch_unwind(|| b_clone.unwrap_c()).unwrap_err();
let c_clone = c.clone();
std::panic::catch_unwind(|| c_clone.unwrap_a()).unwrap_err();
let c_clone = c.clone();
std::panic::catch_unwind(|| c_clone.unwrap_b()).unwrap_err();
let c_clone = c.clone();
assert_eq!("s1", c_clone.unwrap_c());
}
#[test]
fn test_take() {
let same_a: OptionAbc<u8, u8, u8> = OptionAbc::A(42_u8);
let same_b: OptionAbc<u8, u8, u8> = OptionAbc::B(42_u8);
let same_c: OptionAbc<u8, u8, u8> = OptionAbc::C(42_u8);
assert_eq!(42_u8, same_a.take());
assert_eq!(42_u8, same_b.take());
assert_eq!(42_u8, same_c.take());
}
}