Implementing caching for recursive functions.swift

func cached<In: Hashable, Out>(_ computation: @escaping ((In) -> Out, In) -> Out) -> (In) -> Out {
    var cache = [In: Out]()
    
    func wrap(_ input: In) -> Out {
        if let cachedValue = cache[input] {
            return cachedValue
        } else {
            let result = computation(wrap, input)
            cache[input] = result
            return result
        }
    }
    
    return wrap
}