Protocol Conformance for Tuples / Anonymous Structs

[taylorswift]

@NSExceptional

My main concerns are a) since it's so similar to the existing ExpressibleBy___Literal protocols, I think it makes more sense for the API to resemble that that than to add something entirely new like a tuple init(...) keyword

at some point we’re going to want to make the literal protocols completely lexical, as described here, and that will require overloaded literal-inits if we want to get all the mileage out of that feature, so i don’t see why @tupleLiteral can’t piggyback on that when it comes time.

// invokes Double.init(sign: .plus, base: .decimal, digits:[9, 8, 9, 1])
let x:Double = 1989

// invokes Double.init(sign: .plus, base: .hexadecimal, 
//                 fraction: [10], digits:[1, 15], exponent: [2, 1])
let y:Double = 0xF1.Ap12

@NSExceptional

I don't want it to only apply to structs, like you seemed to imply here:

no reason why classes or enums should get left out, im just using structs as an example.