mirror of
https://github.com/apple/swift.git
synced 2025-12-14 20:36:38 +01:00
cca27d02a0
Keep calm: remember that the standard library has many more public exports than the average target, and that this contains ALL of them at once. I also deliberately tried to tag nearly every top-level decl, even if that was just to explicitly mark things @internal, to make sure I didn't miss something. This does export more than we might want to, mostly for protocol conformance reasons, along with our simple-but-limiting typealias rule. I tried to also mark things private where possible, but it's really going to be up to the standard library owners to get this right. This is also only validated against top-level access control; I haven't fully tested against member-level access control yet, and none of our semantic restrictions are in place. Along the way I also noticed bits of stdlib cruft; to keep this patch understandable, I didn't change any of them. Swift SVN r19145
54 lines
1.5 KiB
Swift
54 lines
1.5 KiB
Swift
//===--- EmptyCollection.swift - A collection with no elements ------------===//
|
|
//
|
|
// This source file is part of the Swift.org open source project
|
|
//
|
|
// Copyright (c) 2014 - 2015 Apple Inc. and the Swift project authors
|
|
// Licensed under Apache License v2.0 with Runtime Library Exception
|
|
//
|
|
// See http://swift.org/LICENSE.txt for license information
|
|
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// Sometimes an operation is best expressed in terms of some other,
|
|
// larger operation where one of the parameters is an empty
|
|
// collection. For example, we can erase elements from an Array by
|
|
// replacing a subrange with the empty collection.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
@public struct EmptyGenerator<T> : Generator, Sequence {
|
|
@public func generate() -> EmptyGenerator {
|
|
return self
|
|
}
|
|
|
|
@public mutating func next() -> T? {
|
|
return nil
|
|
}
|
|
}
|
|
|
|
@public struct EmptyCollection<T> : Collection {
|
|
@public typealias IndexType = Int
|
|
|
|
@public var startIndex: IndexType {
|
|
return 0
|
|
}
|
|
|
|
@public var endIndex: IndexType {
|
|
return 0
|
|
}
|
|
|
|
@public func generate() -> EmptyGenerator<T> {
|
|
return EmptyGenerator()
|
|
}
|
|
|
|
@public subscript(i: IndexType) -> T {
|
|
_preconditionFailure("Index out of range")
|
|
}
|
|
}
|
|
|
|
// Specialization of countElements for EmptyCollection<T>
|
|
@public func ~> <T>(x:EmptyCollection<T>, _:(_CountElements, ())) -> Int {
|
|
return 0
|
|
}
|