Tokamak/Sources/TokamakCore/App/Scenes/_SceneModifier.swift

47 lines
1.4 KiB
Swift

// Copyright 2020 Tokamak contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// Created by Carson Katri on 7/20/20.
//
public protocol _SceneModifier {
associatedtype Body: Scene
typealias SceneContent = _SceneModifier_Content<Self>
func body(content: SceneContent) -> Self.Body
}
public struct _SceneModifier_Content<Modifier>: Scene where Modifier: _SceneModifier {
public let modifier: Modifier
public let scene: _AnyScene
@_spi(TokamakCore)
public var body: Never {
neverScene("_SceneModifier_Content")
}
}
public extension Scene {
func modifier<Modifier>(_ modifier: Modifier) -> ModifiedContent<Self, Modifier> {
.init(content: self, modifier: modifier)
}
}
public extension _SceneModifier where Body == Never {
func body(content: SceneContent) -> Body {
fatalError("""
\(self) is a primitive `_SceneModifier`, you're not supposed to run `body(content:)`
""")
}
}