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Merge pull request #78092 from Azoy/enumerated-collection
[stdlib] Conditionally conform EnumeratedSequence to Collection(s)
2 parents 223ebd2 + a55c9c7 commit 25b10eb

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-91
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10 files changed

+522
-91
lines changed

‎Runtimes/Core/core/CMakeLists.txt

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@@ -72,6 +72,7 @@ add_library(swiftCore
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DropWhile.swift
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Dump.swift
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EmptyCollection.swift
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EnumeratedSequence.swift
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Equatable.swift
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ErrorType.swift
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ExistentialCollection.swift

‎stdlib/private/StdlibCollectionUnittest/MinimalCollections.swift

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@@ -1615,6 +1615,167 @@ public struct MinimalBidirectionalCollection<T> : BidirectionalCollection {
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internal let _collectionState: _CollectionState
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}
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/// A minimal implementation of `Collection` with extra checks.
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public struct MinimalBidirectionalRandomAccessCollection<T> : BidirectionalCollection, RandomAccessCollection {
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/// Creates a collection with given contents, but a unique modification
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/// history. No other instance has the same modification history.
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public init<S : Sequence>(
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elements: S,
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underestimatedCount: UnderestimatedCountBehavior = .value(0)
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) where S.Element == T {
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self._elements = Array(elements)
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self._collectionState = _CollectionState(
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newRootStateForElementCount: self._elements.count)
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switch underestimatedCount {
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case .precise:
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self.underestimatedCount = _elements.count
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case .half:
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self.underestimatedCount = _elements.count / 2
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case .overestimate:
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self.underestimatedCount = _elements.count * 3 + 5
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case .value(let count):
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self.underestimatedCount = count
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}
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}
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public let timesMakeIteratorCalled = ResettableValue(0)
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public func makeIterator() -> MinimalIterator<T> {
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timesMakeIteratorCalled.value += 1
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return MinimalIterator(_elements)
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}
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public typealias Index = MinimalIndex
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internal func _index(forPosition i: Int) -> MinimalIndex {
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return MinimalIndex(
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collectionState: _collectionState,
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position: i,
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startIndex: _elements.startIndex,
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endIndex: _elements.endIndex)
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}
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internal func _uncheckedIndex(forPosition i: Int) -> MinimalIndex {
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return MinimalIndex(
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_collectionState: _collectionState,
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uncheckedPosition: i)
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}
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public let timesStartIndexCalled = ResettableValue(0)
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public var startIndex: MinimalIndex {
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timesStartIndexCalled.value += 1
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return _uncheckedIndex(forPosition: _elements.startIndex)
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}
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public let timesEndIndexCalled = ResettableValue(0)
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public var endIndex: MinimalIndex {
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timesEndIndexCalled.value += 1
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return _uncheckedIndex(forPosition: _elements.endIndex)
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}
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public func _failEarlyRangeCheck(
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_ index: MinimalIndex,
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bounds: Range<MinimalIndex>
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) {
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: index.position),
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index)
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: bounds.lowerBound.position),
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bounds.lowerBound)
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: bounds.upperBound.position),
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bounds.upperBound)
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expectTrapping(
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index.position,
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in: bounds.lowerBound.position..<bounds.upperBound.position)
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}
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public func _failEarlyRangeCheck(
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_ range: Range<MinimalIndex>,
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bounds: Range<MinimalIndex>
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) {
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: range.lowerBound.position),
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range.lowerBound)
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: range.upperBound.position),
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range.upperBound)
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: bounds.lowerBound.position),
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bounds.lowerBound)
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_expectCompatibleIndices(
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_uncheckedIndex(forPosition: bounds.upperBound.position),
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bounds.upperBound)
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expectTrapping(
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range.lowerBound.position..<range.upperBound.position,
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in: bounds.lowerBound.position..<bounds.upperBound.position)
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}
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public func index(after i: MinimalIndex) -> MinimalIndex {
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_failEarlyRangeCheck(i, bounds: startIndex..<endIndex)
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return _uncheckedIndex(forPosition: i.position + 1)
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}
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public func index(before i: MinimalIndex) -> MinimalIndex {
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// FIXME: swift-3-indexing-model: perform a range check and use
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// return _uncheckedIndex(forPosition: i.position - 1)
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return _index(forPosition: i.position - 1)
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}
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public func distance(from start: MinimalIndex, to end: MinimalIndex)
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-> Int {
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// FIXME: swift-3-indexing-model: perform a range check properly.
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if start != endIndex {
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_failEarlyRangeCheck(start, bounds: startIndex..<endIndex)
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}
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if end != endIndex {
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_failEarlyRangeCheck(end, bounds: startIndex..<endIndex)
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}
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return end.position - start.position
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}
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public func index(_ i: Index, offsetBy n: Int) -> Index {
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// FIXME: swift-3-indexing-model: perform a range check properly.
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if i != endIndex {
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_failEarlyRangeCheck(i, bounds: startIndex..<endIndex)
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}
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return _index(forPosition: i.position + n)
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}
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public subscript(i: MinimalIndex) -> T {
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get {
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_failEarlyRangeCheck(i, bounds: startIndex..<endIndex)
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return _elements[i.position]
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}
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}
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public subscript(bounds: Range<MinimalIndex>) -> Slice<MinimalBidirectionalRandomAccessCollection<T>> {
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get {
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_failEarlyRangeCheck(bounds, bounds: startIndex..<endIndex)
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return Slice(base: self, bounds: bounds)
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}
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}
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public var underestimatedCount: Int
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internal var _elements: [T]
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internal let _collectionState: _CollectionState
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}
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/// A minimal implementation of `Collection` with extra checks.
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public struct MinimalRangeReplaceableBidirectionalCollection<T> : BidirectionalCollection, RangeReplaceableCollection {

‎stdlib/public/core/Algorithm.swift

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@@ -74,91 +74,3 @@ public func max<T: Comparable>(_ x: T, _ y: T, _ z: T, _ rest: T...) -> T {
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}
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return maxValue
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}
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/// An enumeration of the elements of a sequence or collection.
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///
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/// `EnumeratedSequence` is a sequence of pairs (*n*, *x*), where *n*s are
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/// consecutive `Int` values starting at zero, and *x*s are the elements of a
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/// base sequence.
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///
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/// To create an instance of `EnumeratedSequence`, call `enumerated()` on a
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/// sequence or collection. The following example enumerates the elements of
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/// an array.
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///
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/// var s = ["foo", "bar"].enumerated()
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/// for (n, x) in s {
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/// print("\(n): \(x)")
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/// }
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/// // Prints "0: foo"
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/// // Prints "1: bar"
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@frozen
95-
public struct EnumeratedSequence<Base: Sequence> {
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@usableFromInline
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internal var _base: Base
98-
99-
/// Construct from a `Base` sequence.
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@inlinable
101-
internal init(_base: Base) {
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self._base = _base
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}
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}
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extension EnumeratedSequence: Sendable where Base: Sendable {}
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extension EnumeratedSequence {
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/// The iterator for `EnumeratedSequence`.
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///
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/// An instance of this iterator wraps a base iterator and yields
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/// successive `Int` values, starting at zero, along with the elements of the
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/// underlying base iterator. The following example enumerates the elements of
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/// an array:
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///
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/// var iterator = ["foo", "bar"].enumerated().makeIterator()
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/// iterator.next() // (0, "foo")
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/// iterator.next() // (1, "bar")
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/// iterator.next() // nil
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///
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/// To create an instance, call
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/// `enumerated().makeIterator()` on a sequence or collection.
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@frozen
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public struct Iterator {
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@usableFromInline
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internal var _base: Base.Iterator
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@usableFromInline
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internal var _count: Int
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/// Construct from a `Base` iterator.
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@inlinable
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internal init(_base: Base.Iterator) {
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self._base = _base
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self._count = 0
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}
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}
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}
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extension EnumeratedSequence.Iterator: Sendable where Base.Iterator: Sendable {}
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extension EnumeratedSequence.Iterator: IteratorProtocol, Sequence {
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/// The type of element returned by `next()`.
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public typealias Element = (offset: Int, element: Base.Element)
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/// Advances to the next element and returns it, or `nil` if no next element
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/// exists.
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///
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/// Once `nil` has been returned, all subsequent calls return `nil`.
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@inlinable
150-
public mutating func next() -> Element? {
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guard let b = _base.next() else { return nil }
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let result = (offset: _count, element: b)
153-
_count += 1
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return result
155-
}
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}
157-
158-
extension EnumeratedSequence: Sequence {
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/// Returns an iterator over the elements of this sequence.
160-
@inlinable
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public __consuming func makeIterator() -> Iterator {
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return Iterator(_base: _base.makeIterator())
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}
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}

‎stdlib/public/core/CMakeLists.txt

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Original file line numberDiff line numberDiff line change
@@ -76,6 +76,7 @@ split_embedded_sources(
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EMBEDDED DropWhile.swift
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NORMAL Dump.swift
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EMBEDDED EmptyCollection.swift
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EMBEDDED EnumeratedSequence.swift
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EMBEDDED Equatable.swift
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EMBEDDED ErrorType.swift
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EMBEDDED ExistentialCollection.swift

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