37 lines
1.2 KiB
Swift
37 lines
1.2 KiB
Swift
// Copyright 2022 Tokamak contributors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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// Created by Carson Katri on 6/20/22.
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//
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/// A key that stores a value that can be accessed via a `LayoutSubview`.
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public protocol LayoutValueKey {
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associatedtype Value
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static var defaultValue: Self.Value { get }
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}
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public extension View {
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@inlinable
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func layoutValue<K>(key: K.Type, value: K.Value) -> some View where K: LayoutValueKey {
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// LayoutValueKey uses trait keys under the hood.
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_trait(_LayoutTrait<K>.self, value)
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}
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}
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public struct _LayoutTrait<K>: _ViewTraitKey where K: LayoutValueKey {
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public static var defaultValue: K.Value {
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K.defaultValue
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}
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}
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