This week's episode of John Gruber's podcast, The Talk Show, features a 30-minute interview with Apple's senior vice-president of software, Craig Federighi. The topic is Swift going open source.

People here are idealistic yet really pragmatic, and I think you see that as an Apple characteristic in many, many elements of what we do. And so, teams know what the nature of what we're trying to get done in their area in any given year, the nature of their code base, whether Swift is the right answer for them, or where it's the right answer. Even teams where, for one reason or another, they can't jump right on Objective-C — or rather Objective-C conversion to Swift now. They then use Swift heavily for writing all their unit tests, which is great because then at least as they're introducing new APIs, they're experiencing their own APIs in Swift and then ... sort of eating their own dog food in that regard. We do have some constraints internally which we're addressing, but because we ... I mean, it's something in our closet a little bit, but we still support running 32-bit apps on the Mac. And the 32-bit runtime doesn't actually support Swift right now. And so, what that means is that if we implement a framework that's available to 32-bit code, we actually can't write it in Swift. If that code, if that framework is used across iOS and OS X -- as many of our frameworks are -- that introduces a little stumbling block as well. So teams recognize what's practical and what's not practical and find ways to use Swift wherever they can. There's no shortage of enthusiasm.

The rest of the episode features John Siracusa talking about both the interview and Swift. Give it a listen.