Recursive Reduce Swift

recursivereduce.swift

//Implement Reduce 
func reduceRecursively <A, R>(xs: [A], initialValue: R, combine:(R, A) -> R) -> R {
    if let head = xs.first {
        let tail = Array(dropFirst(xs))
        return reduceRecursively(tail, combine(initialValue, head), combine)
    } else {
        return initialValue
    }
}
 
// Call Reduce 
reduceRecursively([1, 2, 3, 4], 1) {
    $0 + $1
}