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94dac129d4
To limit user confusion when using conditional expressions of type Bool?, we've decided to remove the BooleanType (aka "LogicValue") conformance from optional types. (If users would like to use an expression of type Bool? as a conditional, they'll need to check against nil.) Note: This change effectively regresses the "case is" pattern over types, since it currently demands a BooleanType conformance. I've filed rdar://problem/17791533 to track reinstating it if necessary. Swift SVN r20637
51 lines
1.4 KiB
Swift
51 lines
1.4 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See http://swift.org/LICENSE.txt for license information
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// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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public struct ZipGenerator2<
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E0 : GeneratorType, E1 : GeneratorType
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> : GeneratorType {
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public typealias Element = (E0.Element,E1.Element)
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public init(_ e0: E0, _ e1: E1) {
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baseStreams = (e0,e1)
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}
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public mutating func next() -> Element? {
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var e0 = baseStreams.0.next()
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if e0 == nil { return .None }
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var e1 = baseStreams.1.next()
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if e1 == nil { return .None }
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return .Some((e0!, e1!))
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}
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var baseStreams : (E0,E1)
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}
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public struct Zip2<S0: SequenceType, S1: SequenceType> : SequenceType
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{
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public typealias Stream1 = S0.Generator
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public typealias Stream2 = S1.Generator
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public typealias Generator = ZipGenerator2<Stream1, Stream2>
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public init(_ s0: S0, _ s1: S1) {
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sequences = (s0,s1)
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}
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public func generate() -> Generator {
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return Generator(
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sequences.0.generate(),
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sequences.1.generate())
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}
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var sequences: (S0,S1)
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}
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