swiftlang/swift-corelibs-foundation

Free

The Foundation Project, providing core utilities, internationalization, and OS independence

FreeFree tier

Type

Open Source

Visit Website GitHub (38 stars)

About swiftlang/swift-corelibs-foundation

The Foundation framework defines a base layer of functionality required for almost all applications. It provides primitive classes and introduces several paradigms that define functionality not provided by either the Objective-C runtime and language or Swift standard library and language. This project, swift-corelibs-foundation, provides a compatibility implementation of the Foundation API for platforms where there is no Objective-C runtime. On macOS, iOS, and other Apple platforms, apps should use the Foundation that comes with the operating system. The project is composed of swift-foundation (core implementation of key types like URL, Data, JSONDecoder, Locale, Calendar), Swift Corelibs Foundation (compatibility API for pre-Swift API, providing NSObject, class-based data structures, NSFormatter, NSKeyedArchiver), and Foundation ICU (private library wrapping ICU).

Key Features

Provides a base layer of functionality for Swift applications

Includes core utility classes and data structures

Supports internationalization and localization

Offers OS independence for portability

Compatibility implementation for non-Apple platforms

Includes swift-foundation with types like URL, Data, JSONDecoder, Locale, Calendar

Swift Corelibs Foundation provides NSObject, class-based data structures, NSFormatter, NSKeyedArchiver

Foundation ICU wrapper for consistent internationalization behavior

Pros & Cons

Pros

Open source and free
Part of the official Swift ecosystem
Provides OS independence and portability
Comprehensive internationalization support
Includes both modern swift-foundation and compatibility layers

Cons

Best-effort compatibility with Objective-C Foundation (not a drop-in replacement)
Not intended for use on Apple platforms (use native Foundation)
May have performance or behavior differences from Apple's Foundation
Requires ICU library for some internationalization features

Best For

Developing cross-platform Swift applications that need Foundation API on Linux or WindowsPorting Objective-C code that relies on Foundation to non-Apple platformsBuilding server-side Swift applications with Foundation utilitiesUsing Swift on platforms without Objective-C runtime

FAQ

What is swift-corelibs-foundation?

It is an open-source compatibility implementation of the Foundation framework for Swift on platforms without an Objective-C runtime, such as Linux and Windows.

How does it relate to swift-foundation?

swift-foundation is a shared library providing core implementation of key types like URL and Data. swift-corelibs-foundation provides a broader compatibility API and re-exports swift-foundation modules.

Can I use this on macOS or iOS?

No, Apple platforms should use the Foundation that comes with the operating system. This project is for non-Darwin platforms.