ts95

import Data.List

fib :: Int -> Int
fib 0 = 1
fib 1 = 1
fib n = fib (n - 1) + fib (n - 2)

main :: IO ()
main = putStrLn $ intercalate ", " $ map show $ map fib [0..10]

ts95

import Foundation
import FirebaseDatabase

enum ModelError: Error {
    case invalidProperties
}

protocol Model {
    init?(snapshot: FIRDataSnapshot)
    

ts95

import Foundation
import FirebaseDatabase

struct Book {
    var id: String?
    var isbn: String
    var title: String
    var authors: String
    var year: String
    var country: String

ts95

let db = FIRDatabase.database()
let booksRef = db.reference(withPath: Endpoint.books.path)

var newBook = Book(
    id: nil,
    isbn: "95-0443-843-0",
    title: "Do Androids Dream of Electric Sheep?",
    authors: "Philip K. Dick",
    year: "1968",
    country: "United States",

ts95

let db = FIRDatabase.database()
let bookRef = db.reference(withPath: Endpoint.book("-KnEUaDbm6-snUq_Ojzo").path)
bookRef.observeSingleEvent(of: .value, with: { snapshot in
    guard let book = Book(snapshot: snapshot) else { return }
    print(book.title)
})

ts95

import UIKit

protocol ReusableView: class {
    static var defaultReuseIdentifier: String { get }
}

extension ReusableView where Self: UIView {

    static var defaultReuseIdentifier: String {
        return String(describing: self)

ts95

let book = FirestoreBook(
    isbn: "95-0443-843-0",
    title: "Do Androids Dream of Electric Sheep?",
    authors: ["Philip K. Dick"],
    year: 1968,
    country: "United States",
    createdAt: Date(),
    format: .ebook,
    award: nil)

ts95

let book = FirestoreBook(
    documentID: nil,
    isbn: "95-0443-843-0",
    title: "Do Androids Dream of Electric Sheep?")

let firestore = Firestore.firestore()
let ref = firestore.collection("books").document()
ref.setModel(book)

ts95

let firestore = Firestore.firestore()
let ref = firestore.document("books/95-0443-843-0")
ref.getModel(FirestoreBook.self) { book, error in
    guard let book = book else { return }
    print("The book \(book.title) was published in \(book.year).")
}

ts95

struct FirestoreBook {
    let documentID: String!
    var isbn: String
    var title: String
}

extension FirestoreBook: FirestoreModel {

    init?(modelData: FirestoreModelData) {
        try? self.init(