I agree. I have a heavily multithreaded program, and I had to write my own thread-safe data structures, and spent ages debugging and tuning them. Then one wee

I agree. I have a heavily multithreaded program, and I had to write my own thread-safe data structures, and spent ages debugging and tuning them. Then one weekend I read about Clojure core.async, and wrote a little 50-line prototype (much simpler and easier), and got something that worked correctly every time (first try!), and was (without tuning) only about 15% slower than my production system. I've read about how they plan to glue some better concurrency support onto Swift, and I dread it. The language is already so complex that they're having trouble with the basics. I've got workarounds in my app because switching on an enum doesn't always work right (SR-1121). Now we want to add concurrency after the fact? Oh boy. If I had to do it again, I'd definitely write the core of my software in some other language (maybe Clojure), and just use Swift for the GUI. Swift looks like a language designed for AppKit/UIKit, so it's fine if that's all you need it to do.