// Higher order functions, being curried. Considered pure functional, because they don't have any side effects
// (mutate any given data). They just derive data from data.
let plus = { (first: Int) in { (second: Int) in first + second } }
let multiplesOf = { (first: Int) in { (second: Int) in second % first != 0 } }

// Just a simple first class function, not per se functional. Usable to reduce a collection of integers into the total.
let total: (Int, Int) -> Int = { $0 + $1 }

let calculation = (1...30)
    .map(plus(2))
    .filter(multiplesOf(5))
    .reduce(0, total)

print("\(calculation) vape nationnn")