Implementing Sequence & IteratorProtocol, Swift 3

sequence_iterator.swift

import Foundation

class Cell {

    var name: String

    init(_ name: String) {
        self.name = name
    }
}

class Row: Sequence, IteratorProtocol {

    typealias Element = Cell
    var iteratorIndex: Int = 0

    var cells = [Cell]()

    init(cellNames: String...) {
        for name in cellNames {
            cells.append(Cell(name))
        }
    }

    func next() -> Cell? {

        if iteratorIndex >= cells.count {
            return nil
        }

        defer {
            iteratorIndex += 1
        }

        return cells[iteratorIndex]
    }

    func makeIterator() -> Row {
        self.iteratorIndex = 0
        return self
    }
}

let row = Row(cellNames: "one", "two", "three")

for cell in row {
    print(cell.name)
}

for (index, cell) in row.enumerated() {
    print("[\(index), \(cell.name)]")
}