Memberwise Initializer in Swift explained with Code Examples

SPI Joins Apple, and Swift Moves Toward Self-Hosting -- Fatbobman's Swift Weekly #142

Swift Package Index (SPI) has joined Apple, signaling a major step toward a trustworthy, official Swift package registry with improved discovery, signing, and distribution. Separately, the Swift compiler is moving toward self-hosting by dropping the requirement to build using only a C++ toolchain — core components like the Parser, AST, and Type Checker can now be written in Swift. The newsletter also highlights: a Swift-like environment running on an Apple II with a 1 MHz 6502 CPU, a WebAssembly-based OTA update system for native Swift iOS apps using WasmKit, deep dives into SwiftUI's attribute graph internals, SwiftUI toolbar API improvements from WWDC 26, a private UIKit _UIPortalView component for live mirroring effects, and an iOS Simulator camera extension tool for testing camera-dependent features.

Bringing Swift To The Apple II

Developer Yeo Kheng Meng built a Swift development environment that targets the Apple II platform, covering the original 1977 model through the IIe. Since the Apple II runs a 1 MHz 6502 CPU, the approach compiles Swift to bytecode executed by a virtual machine running on the 6502. The setup requires a 48 KB RAM upgrade but otherwise targets stock hardware. Claude Code and GPT 4.5 Codex assisted in piecing the project together.

“Trait-ifying” our libraries to reduce transitive dependencies

Point-Free is adopting SwiftPM traits across their Swift libraries to let users opt out of transitive dependencies they don't need. Using SwiftNavigation as a test bed, developers can now specify traits like CasePaths and Perception in Package.swift to avoid pulling in libraries like CustomDump, IssueReporting, and Sharing. The Dependencies library also supports traits to omit clock/Combine scheduler registrations and even Foundation/FoundationNetworking for Wasm and Android targets. Xcode provides a new UI for managing these traits. More libraries, including ComposableArchitecture 2.0, are getting the same treatment.

New macros for SwiftNavigation

SwiftNavigation 2.9.0 introduces two new Swift macros. The first, @CaseBindable, lets you derive bindings to individual enum-case payloads, enabling exhaustive switch statements over SwiftUI Binding<Enum> values to extract typed bindings for each case. The second, @UITransactionEntry, reduces boilerplate when defining custom UITransaction keys — mirroring SwiftUI's @Entry macro but for the library's platform-independent UITransaction type. Both macros are back-deployed to iOS 13.

Taking Control of Toolbar Items in SwiftUI

SwiftUI introduces several new Toolbar APIs giving developers finer control over toolbar item visibility and behavior across platforms. Key additions include the visibilityPriority modifier for ToolbarContent (with automatic, low, and high options), the ToolbarOverflowMenu type for explicitly collapsing groups of items, the topBarPinnedTrailing placement to keep items pinned to the top bar trailing edge, and the toolbarMinimizeBehavior modifier to minimize navigation, tab, bottom, or window bars on scroll. These APIs help balance SwiftUI's adaptive behavior with explicit developer control across iOS, iPadOS, and macOS.

Issue 756 – iOS Dev Weekly

Số 756 của iOS Dev Weekly đưa tin Swift Package Index chính thức gia nhập Apple, với người sáng lập Dave Verwer cũng tham gia công ty. Bản tin cũng đề cập đến những cải tiến trong iOS 27 như chế độ Recovery giống Mac và nâng cấp AsyncImage trong SwiftUI (hỗ trợ URLRequest, chia sẻ URLSession tùy chỉnh), cùng với các chủ đề khác như cải tiến concurrency trong Swift 6.4, nghiên cứu sâu về mô hình đồ thị của SwiftUI, tiện ích CrashReportExtension mới của Apple cho báo cáo lỗi ngoài tiến trình, và khám phá _UIPortalView riêng tư của UIKit để phản chiếu live view.

Để cập nhật những thay đổi mới nhất trong Swift, iOS và UIKit—và hiểu cách áp dụng các tính năng như AsyncImage và CrashReportExtension để nâng cao hiệu suất và quản lý lỗi trong ứng dụng của mình.