New concurrency features in Swift 5.5 focus on async/await for easier asynchronous coding.
Structured concurrency introduces organized task management and actors for concurrent entity communication.
Swift 5.5's actors streamline resource access and main actors ensure UI operations run smoothly.
Deep dives
Introduction of New Concurrency Features in Swift 5.5
The podcast discusses the introduction of new concurrency features in Swift 5.5, highlighting the major focus of WWDC 2021 on these features. They have been developed for a long time both internally at Apple and in the Swift open source community. The new features aim to make it easier to write asynchronous code using normal control flow constructs, introduce structured concurrency to manage interactions between concurrent tasks, and implement actors to facilitate communication among concurrent entities.
Async Await and its Benefits in Asynchronous Code
The episode delves into the benefits of using async await in asynchronous programming. Async await simplifies the writing of asynchronous code by replacing deeply nested completion handlers with a more linear code structure. By pushing off the management of asynchronous behavior to the Swift language itself, it enhances readability and simplifies error handling. Async await seamlessly integrates with existing Swift features like throwing functions, enabling easier error propagation and making control flow more robust and predictable.
Structured Concurrency and the Role of Tasks and Actors
The podcast explores structured concurrency and its role in managing tasks and actors. Structured concurrency introduces a more organized approach to concurrency, reminiscent of structured programming, enabling easier management of concurrent tasks and related asynchronous operations. Tasks play a significant role in structured concurrency by creating logical threats of execution that work independently during asynchronous operations. Actors provide a structured way to handle concurrent entities, allowing isolation of state and logic to ensure more manageable and correct concurrent code.
Introduction of Actors in Swift 5.5
Actors, a new tool introduced in Swift 5.5, address complex issues related to concurrency. Actors help manage resource access among multiple tasks efficiently. They provide a structured way to interact with shared resources, ensuring serial execution within the actor to prevent data races. For example, an actor managing server interactions ensures orderly communication with the server and avoids data race issues.
Main Actor Annotation for UI-related Tasks
The main actor, a specialized actor in Swift, focuses on UI-related tasks and guarantees operations are run only on the main thread. Functions and properties marked with the main actor attribute ensure access from the main thread, simplifying UI updates and preventing concurrency issues. By annotating UI components with the main actor attribute, developers streamline UI-related logic and avoid manual thread management for improved code clarity and safety.
Doug Gregor from Apple joins John to discuss Swift 5.5’s new concurrency features in great detail. How do features like async/await and actors work under the hood, and how were those concepts adapted in order to feel right at home within Swift’s existing ecosystem? That, and much more, on this WWDC21 special episode of the show.
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