Microsoft has made available an early preview version of the Windows Bridge for iOS, the set of developer tools previously known as "Project Islandwood."
The tools are just one of several "bridges" that Microsoft announced at its annual Build developer conference in April, designed to lure developers from other platforms to Windows 10.
In this case, the idea is that iOS developers will be able to write Windows Universal Apps in Objective-C, making it easy to port their existing code to Redmond's platform.
The bridge consists of an Objective-C compiler that will be integrated with a future version of Visual Studio, an Objective-C runtime for Windows that provides functions like message passing and automatic reference counting, and a set of header files and libraries that make available a subset of the iOS APIs.
"Our goal with the iOS bridge has never been simply to run iOS apps on Windows," Microsoft's Salmaan Ahmed wrote in a blog post. "Rather, our goal is to help you write great Windows apps that use as much of your existing code and knowledge as possible."
Windows apps written in Objective-C will have full access to the Windows APIs and will run alongside other Universal Apps without additional sandboxing.
Much of the source code to the bridge is being made available on GitHub, here, under the MIT open source license. The exception is the compiler, which is a custom modified version of the LLVM clang compiler that includes code from Visual Studio's cl.exe compiler and will only be available in binary form.
"This is very much a work-in-progress and some of the components we showed at Build in April are not ready yet or still in an early state," Ahmed explained. "Today's release supports building apps that target both Windows 10 and Windows 8.1 built for x86 and x64 processor architectures, and through the fall we'll add additional capabilities as more of the bridge is being completed."
Among those future features will be compiler support for the ARM processor architecture, meaning apps written in Objective-C will be able to run on Windows 10 Mobile, the version of the OS for smartphones, in addition to the desktop PC version.
As for the other half of Redmond's smartphone app porting strategy – "Project Astoria," which is now being called the Windows Bridge for Android – it's still only available in an invite-only preview program.
"Our goal is to have everyone currently on the early access waitlist in the program by the end of August; and we are aiming to release the Windows Bridge for Android as a public beta in the fall," said Microsoft's Kevin Gallo.
There's also the Windows Bridge for web apps, previously known as "Project Westminster," which is available now and allows developers to write web apps that run like native applications on Windows 10.
"Project Centennial," the bridge that helps developers convert classic .Net and Win32-based Windows desktop apps into Universal Apps, will begin testing in 2016. ®