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//! Definition of `AtLeastOneOfTwo`.



// =======================
// === AtLeastOneOfTwo ===
// =======================

/// A struct similar to `Option` and `Either`. It can contain the first value, or the second value,
/// or both of them at the same time.
#[derive(Debug,Clone,Copy)]
#[allow(missing_docs)]
pub enum AtLeastOneOfTwo<T1,T2> {
    First(T1),
    Second(T2),
    Both(T1,T2)
}

impl<T:PartialEq> AtLeastOneOfTwo<T,T> {
    /// Checks whether the values are equal.
    pub fn same(&self) -> bool {
        match self {
            Self::Both(t1,t2) => t1 == t2,
            _                 => false
        }
    }
}

impl<T1,T2> AtLeastOneOfTwo<T1,T2> {
    /// Extracts the first value if exists.
    pub fn first(&self) -> Option<&T1> {
        match self {
            Self::Both(t1,_) => Some(t1),
            Self::First(t1)  => Some(t1),
            _                => None
        }
    }

    /// Extracts the second value if exists.
    pub fn second(&self) -> Option<&T2> {
        match self {
            Self::Both(_,t2) => Some(t2),
            Self::Second(t2) => Some(t2),
            _                => None
        }
    }

    /// Extracts both of the value if exist.
    pub fn both(&self) -> Option<(&T1,&T2)> {
        match self {
            Self::Both(t1,t2) => Some((t1,t2)),
            _                 => None
        }
    }
}