<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="">I agree that keeping braces out of these expressions reads much better also it serves to differentiate statements vs expressions. <div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Dec 13, 2015, at 10:18 AM, Dennis Lysenko <<a href="mailto:dennis.s.lysenko@gmail.com" class="">dennis.s.lysenko@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><p dir="ltr" class="">Just wanted to add, in regards to the argument of "why use 'then' rather than keeping 'if condition { A } else { B }'?": besides my personal opinion that inline braces look out-of-place, braces behave specially in xcode and are notorious for screwing up indentation. For example, since swift was released, multiple non-trailing closure arguments to a single function call (e.g. MagicalRecord.saveWithBlock) are indented inconsistently, with the second closure one indentation level higher than the first. More generally/summarily, braces carry special indentation rules that do not necessarily suit expressions. </p>
<br class=""><div class="gmail_quote"><div dir="ltr" class="">On Sun, Dec 13, 2015, 12:17 PM Paul Ossenbruggen via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word" class=""><div class=""><blockquote type="cite" class=""><div class="">On Dec 13, 2015, at 6:11 AM, Marc Knaup <<a href="mailto:marc@knaup.koeln" target="_blank" class="">marc@knaup.koeln</a>> wrote:</div><br class=""><div class=""><div dir="ltr" class=""><div class="">I also have no preference yet so I'll just throw in some thoughts.</div><div class=""><br class=""></div><div class="">** Existing Code **</div>The removal of the ternary operator would likely affect a lot of existing code.<div class="">A quick search for " ? " (with spaces) over a large app of our team yields 304 results.</div><div class=""><br class=""></div><div class="">Two simpler examples:</div><div class=""><br class=""></div><div class=""><div class=""><font face="monospace, monospace" class="">[</font></div><div class=""><font face="monospace, monospace" class=""><span style="white-space:pre-wrap" class=""> </span>"With Conditions": hasReport ? "yes" : "no",</font></div><div class=""><span style="font-family:monospace,monospace;white-space:pre-wrap" class=""> </span><font face="monospace, monospace" class="">"With Image": hasImage ? "yes" : "no",</font></div><div class=""><span style="font-family:monospace,monospace;white-space:pre-wrap" class=""> </span><font face="monospace, monospace" class="">"With Message": hasMessage ? "yes" : "no",</font></div><div class=""><span style="font-family:monospace,monospace;white-space:pre-wrap" class=""> </span><font face="monospace, monospace" class="">"Shared on Facebook Profile": sharedOnFacebookProfile ? "yes" : "no",</font></div><div class=""><span style="font-family:monospace,monospace;white-space:pre-wrap" class=""> </span><font face="monospace, monospace" class="">"Shared in Facebook Group": sharedOnFacebookGroup ? "yes" : "no",</font></div><div class=""><span style="font-family:monospace,monospace;white-space:pre-wrap" class=""> </span><font face="monospace, monospace" class="">"Shared on Facebook Page": sharedOnFacebookPage ? "yes" : "no"</font></div><div class=""><font face="monospace, monospace" class="">]</font></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class=""><font face="monospace, monospace" class="">view1.alpha = editing ? 1 : 0</font></div><div class=""><font face="monospace, monospace" class="">view2.alpha = editing ? 1 : 0</font></div><div class=""><font face="monospace, monospace" class="">view3.alpha = editing ? 0 : 1</font></div><div class=""><font face="monospace, monospace" class="">view4.alpha = editing ? 1 : 0</font></div></div><div class=""><font face="monospace, monospace" class=""><br class=""></font></div><div class="">I am not sure using <font face="monospace, monospace" class="">if…then…else</font> would make this better to read & understand or worse.</div><div class=""><br class=""></div></div></div></blockquote><div class=""><br class=""></div></div></div><div style="word-wrap:break-word" class=""><div class=""><div class="">there seems to be a lot of people who dislike ternary operators. Other languages also are similar in dumping ternary. </div></div></div><div style="word-wrap:break-word" class=""><div class=""><div class=""><br class=""></div><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class="">** Keyword <font face="monospace, monospace" class="">then</font> **</div><div class="">Making then a keyword would also cost us another word so that change needs to be carefully considered.</div><div class="">In our large app I found just a single instance where <font face="monospace, monospace" class="">then</font> was used for a variable's name:</div><div class=""><span class=""><br class=""></span></div><div class=""><font face="monospace, monospace" class=""><span class="">func</span><span class=""> reloadConfigurationAndThen(then: </span><span class="">() -> Void</span><span class="">) { … }</span></font><br class=""></div><div class=""><p class="">Promises use the word <font face="monospace, monospace" class="">then</font> rather extensively: <a href="https://promisesaplus.com/" target="_blank" class="">https://promisesaplus.com</a></p></div></div><div class="gmail_extra"><br class=""></div></div></blockquote><div class=""><br class=""></div></div></div><div style="word-wrap:break-word" class=""><div class="">Good point. Will think about it.</div></div><div style="word-wrap:break-word" class=""><div class=""><br class=""><blockquote type="cite" class=""><div class=""><div class="gmail_extra"><div class="gmail_quote">On Sun, Dec 13, 2015 at 2:45 PM, Matthew Johnson via swift-evolution <span dir="ltr" class=""><<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>></span> wrote:<br class=""><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="auto" class=""><div class="">I'm not quite sure how I feel about this specific proposal yet but in general I do want to see conditional expressions and removal of the ternary operator.</div><div class=""><br class=""></div><div class="">I would like to see "else if" included in whatever we adopt as the final solution. Is there a reason this is omitted from this proposal? I apologize if that was discussed in the thread. I haven't followed every post. </div><div class=""><br class="">Sent from my iPad</div><div class=""><div class=""><div class=""><br class="">On Dec 12, 2015, at 11:54 PM, Paul Ossenbruggen via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:<br class=""><br class=""></div><blockquote type="cite" class=""><div class=""><div class="">Hello All, </div><div class=""><br class=""></div><div class="">Been sick in bed all day, but decided to try to be productive…</div><div class=""><br class=""></div>I did a rough draft of a proposal for implementing if expressions and switch expressions based upon the discussions we had here. I have tried to keep the scope of the changes as small as possible, only added one keyword and kept things as similar to the existing language constructs as possible. If anyone wants to help me with this, or has feedback, please let me know,<div class=""><br class=""></div><div class=""><a href="https://github.com/possen/swift-evolution/blob/master/0020.md" target="_blank" class="">https://github.com/possen/swift-evolution/blob/master/0020.md</a></div><div class=""><br class=""></div><div class="">Thanks,</div><div class="">- Paul</div><div class=""><br class=""><div class=""><br class=""></div><div class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Dec 12, 2015, at 3:51 PM, Paul Ossenbruggen <<a href="mailto:possen@gmail.com" target="_blank" class="">possen@gmail.com</a>> wrote:</div><br class=""><div class=""><div style="word-wrap:break-word" class="">Implied in using the “then", if…then…else would aways require “else" when using “then” similar to how “guard" requires “else”. This will help to make the difference between statements and expressions clear.<div class=""><br class=""></div><div class="">let x = If cond then X else Y</div><div class=""><br class=""></div><div class="">is the full form, where “else" can not be omitted. </div><div class=""><br class=""></div><div class=""><blockquote type="cite" class=""><div class="">On Dec 12, 2015, at 12:59 PM, Paul Ossenbruggen <<a href="mailto:possen@gmail.com" target="_blank" class="">possen@gmail.com</a>> wrote:</div><br class=""><div class=""><div style="word-wrap:break-word" class=""><div class=""><br class=""></div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Dec 12, 2015, at 12:37 PM, Andrey Tarantsov via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank" class="">swift-evolution@swift.org</a>> wrote:</div><br class=""><div class=""><div style="word-wrap:break-word" class=""><div class="">1. I would really hate to explain to someone when <b class="">if</b> needs a <b class="">then</b> and when it doesn't. That's the sort of inconsistency that shouldn't be added lightly.</div></div></div></blockquote><div class=""><br class=""></div><div class="">agreed definitely want to be careful with that. I think with braces meaning statements that differentiation can be made clear. I would certainly start with statements when describing, just as you usually don’t talk about the ternary operator until later. </div></div><div class=""><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap:break-word" class=""><div class="">3. If we can somehow solve all of this, I think I'll be +1 for replacing (A ? B : C) with some sort of (<b class="">if</b> A <b class="">then</b> B <b class="">else</b> C).</div></div></div></blockquote><div class=""><br class=""></div>Yes that would be great.</div><div class=""><br class=""><blockquote type="cite" class=""><div class=""><div style="word-wrap:break-word" class=""><div class=""><br class=""></div><div class="">4. Generally, I wonder how hard would it be for all statements to be usable as expressions? Why didn't Swift go that way from the start?</div></div></div></blockquote><div class=""><br class=""></div><div class="">The biggest problem statement is you don’t need to exhaustively specify every outcome:</div><div class=""><br class=""></div><div class="">if cond {</div><div class=""><span style="white-space:pre-wrap" class=""> </span>print(“hello”)</div><div class="">}</div><div class=""><br class=""></div><div class="">whereas in an expression you have to specify what happens in the else.</div><div class=""><br class=""></div><div class="">let say = if cond then “hello” else “goodbye"</div></div><div class=""><br class=""></div><div class="">unless you go seriously off the deep end:</div><div class=""><br class=""></div><div class="">let say = if cond then “hello” </div><div class=""><br class=""></div><div class=""> “say" then becomes an optional, *shudder*</div><div class=""><br class=""></div><div class=""><br class=""></div></div></div></blockquote></div><br class=""></div></div></blockquote></div><br class=""></div></div>
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