safina-select 0.1.4

#![forbid(unsafe_code)]

use core::fmt::{Debug, Display, Formatter};

pub enum OptionAb<A, B> {
    A(A),
    B(B),
}

impl<T> OptionAb<T, T> {
    pub fn take(self) -> T {
        match self {
            OptionAb::A(value) | OptionAb::B(value) => value,
        }
    }
}

impl<A, B> OptionAb<A, B> {
    pub fn as_ref(&self) -> OptionAb<&A, &B> {
        match self {
            OptionAb::A(value) => OptionAb::A(value),
            OptionAb::B(value) => OptionAb::B(value),
        }
    }
    pub fn a(&self) -> Option<&A> {
        match self {
            OptionAb::A(value) => Some(value),
            OptionAb::B(_) => None,
        }
    }
    pub fn b(&self) -> Option<&B> {
        match self {
            OptionAb::A(_) => None,
            OptionAb::B(value) => Some(value),
        }
    }
}

impl<A: Debug, B: Debug> OptionAb<A, B> {
    /// # Panics
    /// Panics if `self` is not an `OptionAB::A`.
    pub fn unwrap_a(self) -> A {
        match self {
            OptionAb::A(value) => value,
            OptionAb::B(_) => panic!("expected OptionAB::A(_) but found {:?}", self),
        }
    }
    /// # Panics
    /// Panics if `self` is not an `OptionAB::B`.
    pub fn unwrap_b(self) -> B {
        match self {
            OptionAb::A(_) => panic!("expected OptionAB::B(_) but found {:?}", self),
            OptionAb::B(value) => value,
        }
    }
}

impl<A: Clone, B: Clone> Clone for OptionAb<A, B> {
    fn clone(&self) -> Self {
        match self {
            OptionAb::A(value) => OptionAb::A(value.clone()),
            OptionAb::B(value) => OptionAb::B(value.clone()),
        }
    }
}

impl<A: Debug, B: Debug> Debug for OptionAb<A, B> {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
        match self {
            OptionAb::A(value) => write!(f, "OptionAB::A({:?})", value),
            OptionAb::B(value) => write!(f, "OptionAB::B({:?})", value),
        }
    }
}

impl<A: Display, B: Display> Display for OptionAb<A, B> {
    fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), std::fmt::Error> {
        match self {
            OptionAb::A(value) => write!(f, "{}", value),
            OptionAb::B(value) => write!(f, "{}", value),
        }
    }
}

impl<A: PartialEq, B: PartialEq> PartialEq for OptionAb<A, B> {
    fn eq(&self, other: &Self) -> bool {
        match (self, other) {
            (OptionAb::A(value), OptionAb::A(other)) if value == other => true,
            (OptionAb::B(value), OptionAb::B(other)) if value == other => true,
            _ => false,
        }
    }
}
impl<A: PartialEq, B: PartialEq> Eq for OptionAb<A, B> {}

#[cfg(test)]
mod tests {
    use super::*;

    fn test_values() -> (OptionAb<bool, u8>, OptionAb<bool, u8>) {
        (OptionAb::A(true), OptionAb::B(42))
    }

    #[test]
    fn test_as_ref() {
        let (a, b) = test_values();
        let _: OptionAb<&bool, &u8> = a.as_ref();
        let _: &u8 = b.as_ref().unwrap_b();
        assert!(*(a.as_ref().unwrap_a()));
        assert_eq!(42_u8, *(b.as_ref().unwrap_b()));
    }

    #[test]
    fn test_accessors() {
        let (a, b) = test_values();
        assert!(*(a.a().unwrap()));
        assert_eq!(None, a.b());
        assert_eq!(None, b.a());
        assert_eq!(42_u8, *(b.b().unwrap()));
    }

    #[test]
    fn test_debug() {
        let (a, b) = test_values();
        assert_eq!("OptionAB::A(true)", format!("{:?}", a));
        assert_eq!("OptionAB::B(42)", format!("{:?}", b));
    }

    #[test]
    fn test_display() {
        let (a, b) = test_values();
        assert_eq!("true", format!("{}", a));
        assert_eq!("42", format!("{}", b));
    }

    #[test]
    fn test_eq() {
        let (a, b) = test_values();
        assert_eq!(OptionAb::A(true), a);
        assert_ne!(OptionAb::A(false), a);
        assert_eq!(OptionAb::B(42_u8), b);
        assert_ne!(OptionAb::B(2_u8), b);
        assert_ne!(a, b);
    }

    #[allow(clippy::redundant_clone)]
    #[test]
    fn test_unwrap() {
        let (a, b) = test_values();
        let a_clone = a.clone();
        assert!(a_clone.unwrap_a());
        let a_clone = a.clone();
        assert_eq!(
            "expected OptionAB::B(_) but found OptionAB::A(true)",
            std::panic::catch_unwind(|| a_clone.unwrap_b())
                .unwrap_err()
                .downcast::<String>()
                .unwrap()
                .as_str()
        );

        let b_clone = b.clone();
        assert_eq!(
            "expected OptionAB::A(_) but found OptionAB::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());
    }

    #[test]
    fn test_take() {
        let same_a: OptionAb<u8, u8> = OptionAb::A(42_u8);
        let same_b: OptionAb<u8, u8> = OptionAb::B(42_u8);
        assert_eq!(42_u8, same_a.take());
        assert_eq!(42_u8, same_b.take());
    }
}