Example of using an Swift enum as a factory.

Font.swift

enum Font {
    enum Style: String {
        case bold = "Bold"
        case regular = "Regular"
    }

    case fontAwesome(size: CGFloat)
    case roboto(size: CGFloat, style: Style)
    case robotoCondensed(size: CGFloat, style: Style)

    var uiFont: UIFont {
        switch self {
        case .fontAwesome(let size):
            return UIFont(name: "FontAwesome", size: size)!

        case .roboto(let size, let style):
             return UIFont(name: "Roboto-\(style.rawValue)", size: size)!

        case .robotoCondensed(let size, let style):
            return UIFont(name: "RobotoCondensed-\(style.rawValue)", size: size)!
        }
    }
}

Usage

Font.roboto(size: 17, style: .regular).uiFont