Loops implemented terribly, in Swift

loops.swift

func while_(@autoclosure(escaping) cond: () -> Bool, body: () -> ()) {
    func goto(label: String) {
        switch label {
        case "cond": goto(cond() ? "body" : "end")
        case "body":
            body()
            goto("cond")
        case "end":
            fallthrough
        default: break
        }
    }
    goto("cond")
}

func for_(value: Int, _ cond: Int -> Bool, _ post: (inout Int) -> (), _ body: Int -> ()) {
    var value = value
    while_(cond(value)) {
        body(value)
        post(&value)
    }
}
var j = 100
while_ (j > 50) {
    print(j)
    j -= 1
}

for_(0, { $0 < 50 }, { $0 += 1 }) {
    print($0)
}