It seems that encoding the entire view hierarchy into the type information unlocks possibilities in the realm of optimizations, transitions, and more. Having a peek behind the curtain of SwiftUI DSL can reflect on some core design principle of SwiftUI.
The best part is that the type information still can be captured even with conditional branching in the view hierarchy, but I’ll certainly save that for the next article. The tuple inside the TupleView now holds all the type information about the underlying view hierarchy. With this example you can see how the type annotations change all over the place as the child view composition changes, even when using modifiers on one of the Text views. Let horizontalStack: HStack)> = HStack(content: closure) In the following piece of standard SwiftUI code, there are numerous compiler feature is working together to provide the convenient SwiftUI DSL experience we all know. However, if you are simply a happy user of SwiftUI, and do not really care about where it came from, this article may not have any good use to you. If you are interested in how SwiftUI actually compiled, then by any means, go ahead. See Understanding_SwiftUI_DSL/TupleView.swift at GitHub effect of incrementing or decrementing a value with the step size of step.
#Swiftui vstack size code#
The complementary repository contains every code that this article discusses, may just skip to it right away. SwiftUI on macOS: Selection in List 5 days ago Allowing you to build UI for. Having that you can gain a pretty precise understanding of what is happening under the hood, what are the actual view types that are generated under the hood. We start with a standard SwiftUI DSL code, then dissect SwiftUI related language features one-by-one, and distill the code down to a “vanilla” Swift implementation without all the syntactic sugar that makes SwiftUI DSL possible. This is the type that most view builder returns. An actual tuple of views, like (Text(), Text()). However, behind every view composition there lies (a rather simple) unsung hero of SwiftUI, the TupleView. Most articles out there are great to have an overview of the language features that makes introduce you to Function builders, Opaque return types, and Implicit returns (not to mention type inference itself, trailing closures, read-only computed properties). Ben runs NSScreencast, which is a video training site for all things iOS and Apple.
This article aims to give you a perspective through code examples by recreating SwiftUI hierarchy with “vanilla” Swift. minLength for requiring a minimum value length. SwiftUI DSL backgrounds were discussed in great lengths when the feature landed.
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