88 lines
1.9 KiB
Swift
88 lines
1.9 KiB
Swift
//
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// Binding.swift
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// Adwaita
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//
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// Created by david-swift on 06.08.23.
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//
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/// A property wrapper for a property of a view that binds the property of the parent view.
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///
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/// ```swift
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/// struct Grandparent: View {
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///
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/// @State private var state = false
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///
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/// var view: Body {
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/// Parent(value: $state)
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/// }
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/// }
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///
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/// struct Parent: View {
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///
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/// @Binding var value: Bool
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///
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/// var view: Body {
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/// Child(value: $value)
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/// }
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///
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/// }
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///
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/// struct Child: View {
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///
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/// @Binding var value: Bool
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///
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/// var view: Body {
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/// // ...
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/// }
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///
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/// }
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/// ```
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@propertyWrapper
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public struct Binding<Value> {
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/// The value.
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public var wrappedValue: Value {
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get {
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getValue()
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}
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nonmutating set {
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setValue(newValue)
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}
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}
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/// Get the value as a binding using the `$` prefix.
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public var projectedValue: Binding<Value> {
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.init {
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wrappedValue
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} set: { newValue in
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wrappedValue = newValue
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}
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}
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/// The closure for getting the value.
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private let getValue: () -> Value
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/// The closure for settings the value.
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private let setValue: (Value) -> Void
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/// Initialize a property that is bound from a parent view.
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/// - Parameters:
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/// - get: The closure for getting the value.
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/// - set: The closure for setting the value.
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public init(get: @escaping () -> Value, set: @escaping (Value) -> Void) {
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self.getValue = get
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self.setValue = set
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}
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/// Initialize a property that does not react to changes in the child view.
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/// - Parameters:
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/// - value: The constant value.
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/// - Returns: The binding.
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public static func constant(_ value: Value) -> Binding<Value> {
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.init {
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value
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} set: { _ in
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}
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}
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}
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