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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift open source project
//
// Copyright (c) 2025 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
//
//===----------------------------------------------------------------------===//
/// Represents a type whose instances can be "empty".
public protocol EmptyState {
var isEmpty: Bool { get }
}
extension EmptyState {
/// Returns `nil` if this instance is considered empty, otherwise returns `self`.
///
/// This is used to aid in constructing expressions of form `x.isEmpty ? x : y` where `x` is a complex expression, by allowing it to be instead written as `x.nilIfEmpty ?? y`.
public var nilIfEmpty: Self? {
return isEmpty ? nil : self
}
}
// Add more types here as needed
extension Array: EmptyState { }
extension Path: EmptyState { }
extension String: EmptyState { }
extension Substring: EmptyState { }
extension Set: EmptyState { }
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