I’m having the worst time trying to get newer Swift snapshots to compile and link code — let alone getting Swift built by hand:

Unfortunately, the Swift change log, which goes in reverse chronological order is slightly messed up. I can’t find a single canonical Beta 3 cutoff where everything before that point is implemented, and after is pending.

SE-0099, which separates conditional clauses with commas while eliminating where from associated boolean conditions is implemented.

if let x = x where x % 2 == 1 { ... } // does not compile
if let x = x, x % 2 == 1 { ... } // compiles

SE-0060 is up and running too, ensuring that default arguments are specified in declaration order.

func foo(a: Int = 2, b: Int = 2, c: Int = 2) {}
foo(a: 1, c: 2) // compiles
foo(c: 1, a: 2) // error: argument 'a' must precede argument 'c'

However, SE-0112, which appears after (“earlier”) than SE-0099 is not.

// SE-0112
let cocoaError = NSError(domain: "org.sadun", code: 42, userInfo: [:])
do {
    throw cocoaError
} catch {
    print(error.code) // bzzt, won't compile
}

Yet SE-0081 (move where clauses to the end of declarations) is working fine.

public func ==== <S1: Sequence, S2: Sequence>(seq1: S1, seq2: S2) -> Bool 
    where
    S1.Iterator.Element == S2.Iterator.Element,
    S1.Iterator.Element: Equatable
{
    return !longZip(seq1, seq2).contains(!=)
}

Right now, I’m hoping hard that Beta 4 will get us super-close to a full “Swift 3”