decisions, decisions...

mfunc.swift

extension Int {
    class func add1(x: Int) -> Int {
        return  x + 1
    }
    
    func add2() -> Int {
        return self + 2
    }
}

func add3(x: Int) -> Int {
    return x + 3
}

// disadvantage of preferring class methods
Int.add1(1)
1.add2()

// advantage of preffering class methods
[1,2,3].map(Int.add1)
[1,2,3].map { x in x.add2() }

// advantage of preferring functions
add3(1)
[1,2,3].map(add3) // wow. much functional.
// disadvantage: other people may hate and fear you