Swift (programming language)

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Swift (programming language)

Swift is a general-purpose, compiled programming language developed by Apple Inc. First introduced in 2014 at Apple's Worldwide Developers Conference (WWDC), Swift was designed as a modern alternative to Objective-C for macOS, iOS, watchOS, and tvOS development. It was later open‑sourced in 2015 under the Apache 2.0 license, extending its use to server-side and cross-platform programming.

Swift emphasizes safety, performance, and expressiveness. Its syntax is influenced by Rust (programming language), Python (programming language), and Ruby (programming language), and it incorporates features such as type inference, optional types, closures, and automatic memory management via Automatic Reference Counting (ARC). The language is designed to be both beginner‑friendly and capable of systems‑level tasks.

History

Development of Swift began in 2010 under the direction of Chris Lattner, then a senior engineer at Apple. The language was built on the LLVM compiler infrastructure, allowing high performance and seamless interoperability with C (programming language) and Objective‑C libraries.

• Swift 1.0 (September 2014) – First stable release, bundled with Xcode 6.
• Swift 2.0 (2015) – Introduced error handling with `do‑try‑catch` and protocol extensions.
• Swift 3.0 (2016) – Major API renaming for improved readability; focused on consistency with Foundation (framework).
• Swift 4.0 (2017) – Added archiving/serialization, key paths, and string improvements.
• Swift 5.0 (2019) – Achieved ABI stability on Apple platforms, enabling binary compatibility across OS versions. The runtime is now included in the operating system.
• Swift 5.9 (2023) – Introduced parameter packs, macro system, and ownership concept preview.

Swift continues to evolve through the Swift Evolution process, an open community effort hosted at Swift.org.

Features

Swift includes several hallmark features that distinguish it from other languages:

• Type safety – Variables are always type‑checked at compile time, preventing many common runtime errors.
• Optionals – A distinct type that can hold either a value or `nil`, forcing explicit handling of missing data.
• Memory safety – Automatic Reference Counting (ARC) manages memory without garbage collection; the compiler enforces exclusive access to memory locations.
• Closures – First‑class functions with capture semantics, similar to blocks in C and lambdas in other languages.
• Protocol‑oriented programming – Protocols can define interfaces, and protocol extensions provide default implementations, encouraging composition over inheritance.
• Extensibility – Developer‑defined operators, generics, and subscripts allow custom syntax.
• Package manager – The Swift Package Manager (SPM) is the official build system and dependency manager, integrated since Swift 3.0.

Swift is used not only for Apple platforms but also for server‑side development (e.g., Vapor (web framework)), command‑line tools, and even embedded systems through the Swift for TensorFlow project (later evolved into Differentiable Swift).