<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="">Microsofts study is based on C# (no personal hand’s on experience myself) which was modeled after Java.<div class=""><br class=""></div><div class="">As far as I can tell from the code example in the document - it looks like it made the mistake with “null” that Java did (a hole in the type system). </div><div class=""><br class=""></div><div class="">nil in Swift is actually None for optional types - which were a type-safe way of dealing of situations like this. </div><div class=""><br class=""></div><div class="">Which in that case would make the study meaningless since some of the base assumptions do not apply in Swift.</div><div class=""><br class=""></div><div class="">Which comes back to what a few people are asking for … examples, situations where Swift would have a problem that would need this addition.</div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 2016-02-27, at 23:21:08, Amir Michail via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Feb 27, 2016, at 11:19 AM, Ross O'Brien <<a href="mailto:narrativium@gmail.com" class="">narrativium@gmail.com</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><div dir="ltr" class="">The justification for assertions in general is unnecessary. Swift already has assertion functions: "assert" and "precondition" (even though it's still not clear to me why we have two of them). This thread isn't about software assertions.<div class=""><br class=""></div><div class="">This thread is about your := assertion operator. This thread *is* the exploration of it, as it relates to Swift. You think it would be worth including in Swift? Then argue its case. Tell us why := is useful. Provide a code sample of one of the situations you think it would be used so often for. Show us the value.</div></div></div></blockquote><div class=""><br class=""></div><div class="">Again, this would require an empirical study like the Microsoft one. You can’t argue your way through it.</div><br class=""><blockquote type="cite" class=""><div class=""><div dir="ltr" class=""><div class=""><br class=""></div><div class="">Don't expect us to do all the work here. Your suggestions lack sufficient information to make their worth obvious to us. At the moment you're not convincing us that you've thought about your proposal enough to even decide if it was worth pitching, before you pitched it. Please make that effort.</div></div><div class="gmail_extra"><br class=""><div class="gmail_quote">On Sat, Feb 27, 2016 at 4:10 PM, Amir Michail 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"><span class=""><br class="">
> On Feb 27, 2016, at 11:07 AM, Stephen Celis <<a href="mailto:stephen.celis@gmail.com" class="">stephen.celis@gmail.com</a>> wrote:<br class="">
><br class="">
><br class="">
>> On Feb 27, 2016, at 10:57 AM, Amir Michail <<a href="mailto:a.michail@me.com" class="">a.michail@me.com</a>> wrote:<br class="">
>><br class="">
>>> On Feb 27, 2016, at 10:39 AM, Stephen Celis <<a href="mailto:stephen.celis@gmail.com" class="">stephen.celis@gmail.com</a>> wrote:<br class="">
>>><br class="">
>>>> On Feb 27, 2016, at 10:38 AM, Amir Michail <<a href="mailto:a.michail@me.com" class="">a.michail@me.com</a>> wrote:<br class="">
>>>><br class="">
>>>> I think this := would be used so often that it should be part of the language/standard library.<br class="">
>>><br class="">
>>> Would you please justify this? Would you please answer the questions from my reply?<br class="">
>><br class="">
>> See: <a href="http://research.microsoft.com/apps/pubs/default.aspx?id=70290" rel="noreferrer" target="_blank" class="">http://research.microsoft.com/apps/pubs/default.aspx?id=70290</a><br class="">
><br class="">
> See what part? This document provides no justification for any kind of assignment/assertion operator. Please provide additional context around links you share and how they relate to your actual proposal.<br class="">
<br class="">
</span>The justification for assertions in general is empirical and the Microsoft paper provides it.<br class="">
<br class="">
To explore how useful := assertions are in particular would need a study like the Microsoft one that focuses exclusively on := assertions.<br class="">
<div class="HOEnZb"><div class="h5"><br class="">
><br class="">
> In this case your proposal still needs justification. Would you, again, please answer these questions to provide it?<br class="">
><br class="">
> - Why do you want this feature?<br class="">
><br class="">
> - Would you please provide a better, real-world example (perhaps code extracted from a real-world project you've worked on that would benefit) that demonstrates the benefits of your suggestion?<br class="">
><br class="">
> - Can you go into more detail on the the design of the proposal? How it may be implemented? Caveats? Alternatives considered?<br class="">
><br class="">
> --<br class="">
> Stephen<br class="">
<br class="">
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