[boost] [outcome] v2.1 progress report part 2

Currently at the front of the Rapperswil WG21 meeting, and everybody here keeps asking when will Outcome join Boost, and what will the compatibility be with P0709 Zero-overhead deterministic exceptions: Throwing values? So, just to remind folk, I said a few months ago I am targeting the December 2018 release after a period of maturation. This turned out to be highly wise, as a number of interesting bugs turned up - my thanks to the Microsoft compiler team for finding a particular egregious one recently, and my apologies for my fix to that breaking other things which then also had to get fixed. It happens. I am currently refactoring AFIO, which is proposed as the future C++ standard file i/o library in P1031, to use the SG14 proposed standard error object for P0709 Zero-overhead deterministic exceptions which is detailed in P1028. This refactoring isn't complete yet, but it found a few bugs both in Outcome and in P1028. I hope to have it done soon, and that will be a useful milestone reached. What will the compatibility be between Outcome based code and any potential P0709? People ask this, I assume, because of the similarities and that Outcome comes in experimental P1028 std::error flavour. The answer is that I don't know, I can't even speculate yet. Obviously for every Outcome API written like this: outcome func(pars) noexcept; ... if it could be rewritten as: T func(pars) throws; ... then it's semantically equivalent, but not source equivalent. But can we come up with some preprocessor macro trickery or whatever that implements the same thing, but in library code? Very hard to say right now. And just because one can do it, doesn't mean one should do it. But we'll keep our eye on this, and if Outcome can easily implement a safe subset of P0709 for existing compilers, I might raise a mini-review here on Boost to debate a proposal. We'll see how it goes. Thanks to everybody for their patience, and don't forget you can use Outcome right now - no need to wait for entry into Boost - in both Boost and standalone flavours. Niall