[swift-evolution] Lambda function syntax

[Alexander Regueiro]

This is very similar to my proposal. We were later suggesting the use of `=>` in place of `in`, but formerly I suggested essentially what you did here, but with `func` or `\` in place of `>=` to signify the start of a closure expression.

> On 23 Dec 2015, at 10:21, Brent Royal-Gordon <brent at architechies.com> wrote:
> 
> I have to admit I haven't read the entire thread, so maybe I missed discussion of this.
> 
> I, too, don't like the `params in code` syntax. After a year and a half with Swift, I now remember it, but it still reads funny, and I see new developers struggle with it frequently. I've also used Ruby quite a bit, but I really don't like the `||` syntax there either.
> 
> What I would do is pull the parameters/type signature out of the braces and put a symbol in front of them. For example:
> 
> 	let names = people.map => person { person.name }
> 
> 	database.saveRecord(record) => record, error {
> 		if let record = record {
> 			completionHandler(true)
> 		}
> 		else {
> 			handleError(error!)
> 		}
> 	}
> 
> `=>` is used here merely because it's been discussed upthread; I actually think it's a little too heavy for this role, but I don't have a great replacement immediately at hand.
> 
> A no-parameters closure would not require a `=>`; a bare block would still do there. I suppose the capture list would still go before the parameters, but after the `=>`. Other closure features remain the same—you can still use the `$N` implicit parameters, and you can still use `->` to specify a return value, `()` to surround the parameters, `:` to specify exact types, etc.
> 
> -- 
> Brent Royal-Gordon
> Architechies
>