Apple to open source Swift later this year with support for iOS, OS X, and Linux

Apple software chief Craig Federighi made the announcement during Monday's keynote at the company's annual Worldwide Developers Conference. It remains unclear how Apple will govern Swift development in the new open source model —  whether it will tend more toward the Darwin source or WebKit models — though more details are likely to emerge as the release nears.

At the same time, Federighi announced Swift 2, with numerous new features. Developers will be able to use Markdown in comments, pattern matching in "if," and synthesized "headers" in Xcode alongside other improvements like a faster runtime and shorter compile times.

Swift has grown extremely popular since its release one year ago, with thousands of App Store apps taking advantage of the new language. In April, it took the crown as the most-loved language among developers — some 78 percent of programmers currently working with Swift said they were eager to continue developing with it.

Swift 2 will be included in the iOS 9 beta, which will be available to registered developers later today.