I'm a little disappointed with the scope of this writeup. I just finished my first full Swift app this weekend, and by far, the most bothersome part was interacting with the C APIs (CoreMedia, ImageIO, etc.) I would have loved to see more examples of interacting with framework objects like CGImageSources, CMSampleBuffers, etc.

For example, CGImageSourceCreateWithURL() returns an Unmanaged<CGImageSource>!. You can't pass that object to CGImageSourceCreateImageAtIndex(), because it expects a CGImageSource!. Instead, you have to call takeUnretainedValue() on the Unmanaged to extract the raw pointer. Not terribly difficult, just mildly annoying and not well documented. In C/ObjC, you'd just take the return value of the first function and pass it right into the second.

Another example: CMSampleBufferGetImageBuffer() returns a CVImageBuffer!. And CVPixelBufferLockBaseAddress() takes a CVPixelBuffer! as its argument. In C/ObjC, CVPixelBufferRef is typedef'd to CVImageBufferRef, but that doesn't carry over in Swift. I tried to figure out the opaque-pointer voodoo required to convert from one to the other, and eventually gave up, wrote the function in Objective-C, and moved on.

Swift is shaping up to be an excellent language, but at this point, the casting/wrapping/unwrapping hurdles make it difficult for newcomers and experienced developers alike to take advantage of Apple's 15+ year corpus of powerful APIs.