<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hi Geordie,<div class=""><br class=""></div><div class="">The choice of NSData instead of String was very deliberate for NSJSONSerialization. The reason is that JSON is received from disk or the network as a data blob, not a String. Converting it into a String requires figuring out the encoding and doing a conversion. NSJSONSerialization looks at the leading bytes and then parses the data directly instead of converting the entire thing to a String first. This is a major perf boost, since there is usually a huge portion of the data which never needs to be a string (numbers, for example). Only actual result Strings need the conversion.</div><div class=""><br class=""></div><div class="">On a higher-level note, I agree with the approach of implementing the existing API first before considering alternate APIs. There is no doubt that dealing with untyped JSON output in Swift results in a less than ideal experience of casts or other things. I want to think about how to improve it, but first I want to make sure we have our cross-platform story in place. This means that clients of Foundation can simply use the same NSJSONSerialization API that they are used to and get the results that they expect.</div><div class=""><br class=""></div><div class="">- Tony</div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Dec 5, 2015, at 8:58 AM, Geordie Jay <<a href="mailto:geojay@gmail.com" class="">geojay@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><span id="mailbox-conversation" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><div class="">What I’m not so sure about is the most efficient way of working with NSData in this context, considering we are very much assuming the data to have come from a String of some kind (correct me if I’m wrong). So it seems to me like taking NSData insead of just a String is a regression into Objective-C land.</div><div class=""><br class=""></div><div class="">Can anyone explain why we might want to do this rather than working in an idiomatic Swift way (obviously backwards compatibility is a big one – is it the only one?). The only other thing I can think of is that NSData can be streamed. That is going into territory that I haven’t dealt with in Swift yet though. Would love to hear some input from others on this.</div></span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><div class="gmail_quote" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><p class="">On Sat, Dec 5, 2015 at 5:29 PM, Geordie Jay<span class="Apple-converted-space"> </span><span dir="ltr" class=""><<a href="mailto:geojay@gmail.com" target="_blank" class="">geojay@gmail.com</a>></span><span class="Apple-converted-space"> </span>wrote:<br class=""></p><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"><div class=""><span id="mailbox-conversation" class=""><div class=""><div style="margin-top: 0px; margin-bottom: 0px; line-height: normal; font-family: '.AppleSystemUIFont'; color: rgb(73, 79, 80);" class="">I’m not sure about performance hit of calling C from Swift either (it should be statically linked, so I suspect there is none), but the performance is only marginally slower than NSJSONSerialization as is, in the pure Swift version I am making. My test character set is about 2000 characters long, running serialize on it 5000 times, my current Swift-only version takes 1 second for each test run, and the existing (C-backed) NSJSONSerialization takes about 0.75 seconds.</div><div style="margin-top: 0px; margin-bottom: 0px; line-height: normal; font-family: '.AppleSystemUIFont'; min-height: 17px; color: rgb(73, 79, 80);" class=""><br class=""></div><div style="margin-top: 0px; margin-bottom: 0px; line-height: normal; font-family: '.AppleSystemUIFont'; color: rgb(73, 79, 80);" class="">The difference isn’t huge and I suspect with more optimisation of the Swift code and of the standard library (in particular comparing UTF16 strings) this gap would disappear. I for one would be in favour of a pure Swift solution for readability, and also as a challenge to improve the standard library’s performance.</div><div style="margin-top: 0px; margin-bottom: 0px; line-height: normal; font-family: '.AppleSystemUIFont'; min-height: 17px; color: rgb(73, 79, 80);" class=""><br class=""></div><div style="margin-top: 0px; margin-bottom: 0px; line-height: normal; font-family: '.AppleSystemUIFont'; color: rgb(73, 79, 80);" class="">Another thing to note is that Swift is supposed to be future-proofed in terms of UTF String handling (I’m not sure about JSON though, to be honest – is it supposed to support CharSets beyond UTF8?), maybe having the strings decode in UTF16 by default is not such a bad idea, even if it has a minor performance hit for now.</div></div></span><br class=""><br class=""><div class="gmail_quote"><p class="">On Sat, Dec 5, 2015 at 5:17 PM, Tom Leavy<span class="Apple-converted-space"> </span><span dir="ltr" class=""><<a href="mailto:tom@wickr.com" class="">tom@wickr.com</a>></span><span class="Apple-converted-space"> </span>wrote:<br class=""></p><blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex;"><div dir="auto" class=""><div class="">I would rather go right to the end game here and just work on coding up an implementation of JSON encoding / decoding and making it conform to the NSJSONSerialization spec. I can set up a repo for us to work on it. </div><div class=""><br class=""></div><div class="">The main decision here, is do we code a small lib in C and then call it from the Swift side, or do we just write the entire implementation in Swift? From a performance standpoint C is usually my go to, but if we use swift with only structs and we really focus on minimizing use of functions that would be costly / do a lot of profiling and optimization we can get very close to equivalent performance? At least to the level of the current objective c / c version? I'm also not sure of potential performance penalties of calling C functions from swift. Someone with more knowledge will have to weigh in on that one. <br class=""><br class=""><div class=""><span style="background-color: rgba(255, 255, 255, 0);" class="">Thomas Leavy | Wickr Inc.<br class="">VP Mobile Applications & Architecture | <a dir="ltr" href="x-apple-data-detectors://0/1" class="">Newark, NJ</a><br class=""></span></div></div><div class=""><br class="">On Dec 4, 2015, at 6:24 PM, swizzlr <<a href="mailto:me@swizzlr.co" class="">me@swizzlr.co</a>> wrote:<br class=""><br class=""></div><blockquote type="cite" class="">Re: Rules on adding dependencies</blockquote>This e-mail message is intended only for the named recipient(s) above and is covered by the Electronic Communications Privacy Act 18 U.S.C. Section 2510-2521. This e-mail is confidential and may contain information that is privileged or exempt from disclosure under applicable law. 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