Created
June 19, 2018 17:31
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| public struct Pair <Type1, Type2> { | |
| public let first: Type1 | |
| public let second: Type2 | |
| public init (_ first: Type1, _ second: Type2) { | |
| (self.first, self.second) = (first, second) | |
| } | |
| } | |
| extension Pair { | |
| func fill <WrappedType1, WrappedType2> (_ first: WrappedType1, _ second: WrappedType2) -> Pair<WrappedType1, WrappedType2> where Type1 == Optional<WrappedType1>, Type2 == Optional<WrappedType2> { | |
| return Pair<WrappedType1, WrappedType2>(self.first ?? first, self.second ?? second) | |
| } | |
| } | |
| extension Pair where Type1: Sequence, Type2: Sequence { | |
| public enum Zip { | |
| public struct LongestSequence: Sequence { | |
| internal let sequence1: Type1 | |
| internal let sequence2: Type2 | |
| internal init (_ sequence1: Type1, _ sequence2: Type2) { | |
| (self.sequence1, self.sequence2) = (sequence1, sequence2) | |
| } | |
| public struct Iterator: IteratorProtocol { | |
| internal var iterator1: Type1.Iterator | |
| internal var iterator2: Type2.Iterator | |
| internal var reachedEnd = false | |
| internal init (_ iterator1: Type1.Iterator, _ iterator2: Type2.Iterator) { | |
| (self.iterator1, self.iterator2) = (iterator1, iterator2) | |
| } | |
| public mutating func next() -> (Type1.Iterator.Element?, Type2.Iterator.Element?)? { | |
| if self.reachedEnd { | |
| return nil | |
| } | |
| let element1 = self.iterator1.next() | |
| let element2 = self.iterator2.next() | |
| if element1 == nil && element2 == nil { | |
| self.reachedEnd.toggle() | |
| return nil | |
| } | |
| return (element1, element2) | |
| } | |
| } | |
| public func makeIterator () -> Iterator { | |
| return Iterator(self.sequence1.makeIterator(), self.sequence2.makeIterator()) | |
| } | |
| } | |
| public struct ShortestSequence: Sequence { | |
| internal let sequence1: Type1 | |
| internal let sequence2: Type2 | |
| internal init (_ sequence1: Type1, _ sequence2: Type2) { | |
| (self.sequence1, self.sequence2) = (sequence1, sequence2) | |
| } | |
| public struct Iterator: IteratorProtocol { | |
| internal var iterator1: Type1.Iterator | |
| internal var iterator2: Type2.Iterator | |
| internal var reachedEnd = false | |
| internal init (_ iterator1: Type1.Iterator, _ iterator2: Type2.Iterator) { | |
| (self.iterator1, self.iterator2) = (iterator1, iterator2) | |
| } | |
| public mutating func next() -> (Type1.Iterator.Element, Type2.Iterator.Element)? { | |
| if self.reachedEnd { | |
| return nil | |
| } | |
| guard let element1 = self.iterator1.next(), let element2 = self.iterator2.next() else { | |
| self.reachedEnd.toggle() | |
| return nil | |
| } | |
| return (element1, element2) | |
| } | |
| } | |
| public func makeIterator () -> Iterator { | |
| return Iterator(self.sequence1.makeIterator(), self.sequence2.makeIterator()) | |
| } | |
| } | |
| } | |
| public var zip: (shortest: Zip.ShortestSequence, longest: Zip.LongestSequence) { | |
| return (shortest: Zip.ShortestSequence(self.first, self.second), longest: Zip.LongestSequence(self.first, self.second)) | |
| } | |
| } |
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