On Thu, Nov 23, 2017 at 16:45 Kelvin Ma via swift-evolution < swift-evolution@swift.org> wrote:
> > > On Thu, Nov 23, 2017 at 12:32 PM, Tino Heth <2...@gmx.de> wrote: > >> >> a good idea on paper, a disastrous one in practice. What happens if every >> geometry library declares their own Point type? >> >> That would be ugly („disastrous“ imho is a little bit to strong — C++ >> had/has similar issues, and other languages as well) >> But if there would be a simple Point struct in a library that is popular >> (could be achieved by shipping it alongside the stdlib), this problem would >> be solved (there has been a pitch lately, but I guess it faded away >> silently). >> > > it’s ugly in C++ and disastrous in Swift because C++ has fixed layout > guarantees and everyone agrees that z comes after y comes after x, so you > can unsafe-bitcast the foreign C++ points into your own points “for free”. > you can’t do the same thing in Swift > Why do you need to have this ability to unsafe bitcast? Is interconversion between point types such a common operation that it's a performance bottleneck?
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