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Comment by jaxytee | Hacker News Reader

Swift has a built in option type

“if let actualNumber = possibleNumber.toInt() {

    println("\(possibleNumber)  value: \ (actualNumber)")

} else {

    println("\(possibleNumber) could not be converted to an integer")

}”

Nice to see the Apple's language developers embracing functional programming by providing a clean implementation of the Maybe Monad as well as support for closures.

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I love this feature, but it's not quite the Maybe Monad, which lets you assemble a sequence of (possibly failing) statements together, and fail the whole sequence if any of the parts fails (without if-statements or switching of any kind).

'Optional Chaining' sounds like it lets you join thing together to some extent:

https://developer.apple.com/library/prerelease/ios/documenta...

Oh, cool! Straight out of CoffeeScript. Yeah, that's pretty much the monad instance of Maybe.

I don't think this is very functional. First of all, the let binding inside the condition has type bool by itself (instead of the normal let-in construction). Also, it's scope permeates into the body of the if condition. The whole thing is very much like C-style NULL/Not-NULL check:

   if (x = proc()) {printf("%i", x);}

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