swift factory pattern

swift_factory_pattern.swift

import Foundation
protocol ILayout{
    init(_ args:Double...)
}
class Fillet:ILayout{
    required init(_ args:Double...){
        Swift.print("Fillet: " + "\(args.count)")
    }
}
class Margin:ILayout{
    required init(_ args:Double...){
        Swift.print("Margin: " + "\(args.count)")
    }
}

func instance(value:Any, _ layoutClassType:ILayout.Type) -> ILayout{
    let params:Array<Double> = value is Array<Double> ? value as! Array<Double> : [Double(String(value))!];
    let classType:ILayout.Type = layoutClassType
    var instance:ILayout;// = typeOfObject.init(2,2,2,2)
    switch(params.count){
    case 1: instance = classType.init(params[0]); break;
    case 2: instance = classType.init(params[0],params[1]); break;
    case 3: instance = classType.init(params[0],params[1],params[2]); break;
    case 4: instance = classType.init(params[0],params[1],params[2], params[3]); break;
    default:fatalError("ARGUMENT COUNT MISMATCH");
    }
    return instance;
}

let margin:Margin = instance(4,Margin.self) as! Margin
let fillet:Fillet = instance(4,Fillet.self) as! Fillet