[swift-evolution] Better syntax for deferred?

Maury Markowitz maury.markowitz at gmail.com
Sat Jan 2 11:47:37 CST 2016

> On Jan 2, 2016, at 11:48 AM, Sebastian Mecklenburg via swift-evolution <swift-evolution at swift.org> wrote:
> I don’t think it’s confusing, I read ‘defer’ a ‘do it later’ and that’s just what it does. And the deferred calls are not always necessary so they can’t always be placed at the end.

Can you be more specific about "deferred calls are not always necessary"? Do you mean that you could, for instance, place an if in front of the defer? If so one could do the same with always, of course. I'll use your example, slightly expanded, to illustrate

> func testDefer(x: Int) {
>    defer {print("deferred call1")}
>    if x > 1 { defer {print("deferred call2")} }
    print("non-deferred call")
> }

I would rewrite this as:

    func testAlways(x: Int) {
        print("non-deferred call")
        always {
	    print("deferred call1")
            if x > 1 print("deferred call2")

Which is 100% equivalent to your example, but works precisely as you would expect without needing to "be aware" of any "logical consequence"s. The code runs exactly as it appears.

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