Regards (From mobile)
> On Jun 14, 2016, at 8:41 AM, Charlie Monroe <char...@charliemonroe.net> wrote: > >> I used to do low latency java for trading systems... the kind of coding >> where we would go out of our way to avoid ANY intraday gc activity (yes it >> can be done, even for parsing xml files). So we cared about a lot of >> things... But when you look at the numbers above on a 4_000_000 iterations >> loop and say the differential matters? I say you are probably using the >> wrong tools to write your code in the first place, and you should be using >> accelerate. > > Yes, I say it does matter. Of course, 4 million iterations is a fictional > example that rarely occurrs on its own, but gives you an idea that there's > more going on behind the scenes other than pure iteration. > > You're looking at it from a point where one app does one thing and the loop > will have just a few iterations. Try to look at it from a point where the > entire OS, all the processes and kernel are written in Swift (might be > distant future, but Swift is heading that way, isn't it?). > > In such case if each for-loop takes a few extra instruction, then - again - > yes, it matters. I know we're not talking about all for-loops, just those > filtering the sequence - which seems not that common of a case - but my point > is valid, that Swift should provide easily-reachable means to be a "good > citizen". Removing it will lead developers to use .filter(_:) instead, in > order to save lines of code and additional typing. > > While many searches in open source code found a minimum usage of > for-in-where, I think this is not due to it being confusing, but just not > well known, otherwise it would be used a lot more. Most developers that have > prior programming experience will only skim through the Language Guide > itself, which doesn't mention that `where` can be used in for loops (!!!), or > even while loops and there isn't a single example where it would be used. > > Both > https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/ControlFlow.html > and the ePub download on > https://swift.org/documentation/#the-swift-programming-language > > Maybe I'm missing something, but the language guide only mentions `where` for > the switch-case scenario. So the argument (which floated around here) that > this is not being actively used is kind of moot since how could anyone be > using it since it's not properly documented and no one who doesn't closely > watch release notes can possibly know about this. Non-argument... everything that has been removed was documented prior to its removal. > > >> >> As for the ' >> >>> >>> I've previously noted that if/guard-continue come in really close >>> speed-wise, which makes them candidates for a fix-it in case `where` is >>> indeed removed. >>> >>> My response here was solely to Jean-Daniel's note that he mustn't forget to >>> include the lazy accessor, pointing out that even the lazy accessor is >>> slower than using an inline check. >>> >>> >>>> >>>> -- >>>> Brent Royal-Gordon >>>> Architechies >>>> >>> >
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