46 lines
1.4 KiB
Swift
46 lines
1.4 KiB
Swift
//
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// ProxPropertyWrapper.swift
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// VDS
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//
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// Created by Matt Bruce on 7/29/22.
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//
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import Foundation
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//https://www.swiftbysundell.com/articles/accessing-a-swift-property-wrappers-enclosing-instance/
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@propertyWrapper
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public struct AnyProxy<EnclosingSelf, Value> {
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private let keyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>
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public init(_ keyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>) {
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self.keyPath = keyPath
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}
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@available(*, unavailable, message: "The wrapped value must be accessed from the enclosing instance property.")
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public var wrappedValue: Value {
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get { fatalError() }
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set { fatalError() }
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}
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public static subscript(
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_enclosingInstance observed: EnclosingSelf,
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wrapped wrappedKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Value>,
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storage storageKeyPath: ReferenceWritableKeyPath<EnclosingSelf, Self>
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) -> Value {
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get {
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let storageValue = observed[keyPath: storageKeyPath]
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let value = observed[keyPath: storageValue.keyPath]
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return value
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}
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set {
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let storageValue = observed[keyPath: storageKeyPath]
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observed[keyPath: storageValue.keyPath] = newValue
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}
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}
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}
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extension NSObject: ProxyContainer {}
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public protocol ProxyContainer {
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typealias Proxy<T> = AnyProxy<Self, T>
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}
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