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.send { color:#77bb77; }
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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>Can’t we simply overload <code>??</code> to support <code>@autoclosure () -> Never</code> now and remove that overload when <code>Never</code> is the bottom type? Syntactically it would look and do the same.</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1498593135458926848" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 27. Juni 2017 um 21:52:01, Matthew Johnson via swift-evolution (<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div></div><div>
<title class=""></title>
<br class="">
<div>
<blockquote type="cite" class="">
<div class="">On Jun 27, 2017, at 2:49 PM, David Hart 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="">
<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 27 Jun 2017, at 20:23, Dave DeLong 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="">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Also a +1 from me. This is something I always put in to my
code.
<div class=""><br class=""></div>
<div class="">I agree that having `Never` as a bottom type is
interesting, but even if that were the case, the proposed “!!”
operator is still useful, because it short-circuits having to
fatalError() myself. IE:</div>
<div class=""><br class=""></div>
<div class=""><font face="Menlo" class=""><span style="font-size: 11px;" class="">let last = array.last ??
fatalError(“array must not be empty”)</span></font></div>
</div>
</div>
</blockquote>
<div class=""><br class=""></div>
<div class="">The above solution with Never is the better solution
IMHO:</div>
<div class=""><br class=""></div>
<div class="">
<ul class="MailOutline">
<li class="">No new operator</li>
<li class="">More flexible: what if you want something else than a
fatalError? For example, I might want to define a
logAndFatalError() function which stores the error to a log file
before trapping.</li>
</ul>
</div>
</div>
</div>
</div>
</blockquote>
<div><br class=""></div>
<div>+1</div>
<br class="">
<blockquote type="cite" class="">
<div class="">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
<div class=""><br class="">
<blockquote type="cite" class="">
<div class="">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">
<div class="">vs</div>
<div class=""><br class=""></div>
<div class=""><font face="Menlo" class=""><span style="font-size: 11px;" class="">let last = array.last !! “Array must
not be empty"</span></font></div>
<div class=""><br class=""></div>
<div class="">I also think having it “fatalError” in shipping code
is fine, because it’s equivalent to what would happen if you
incorrect force-unwrap.</div>
<div class=""><br class=""></div>
<div class="">Dave<br class="">
<div class=""><br class="">
<div class="">
<blockquote type="cite" class="">
<div class="">On Jun 27, 2017, at 12:08 PM, Zach Waldowski 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="">
<div class="">
<div style="font-family:Arial;" class="">Big +1.<br class=""></div>
<div class="">
<div style="font-family:Arial;" class=""><br class=""></div>
</div>
<div class="">Using `!` is widely seen as a smell. However, the
need for it still arises; they are preconditions, of a sort. It has
become prevalent in my teams’ codebases to do “guard else
preconditionFailure”.<br class=""></div>
<div style="font-family:Arial;" class="">
<div style="font-family:Arial;" class=""><br class=""></div>
</div>
<div style="font-family:Arial;" class="">I like `!!` over something
like `?!`; it follows the pattern that almost every `?` in the
language has an equivalent `!`.<br class=""></div>
<div class="">
<div style="font-family:Arial;" class=""><br class=""></div>
</div>
<div class="">
<div style="font-family:Arial;" class="">The implementation details
are ultimately not relevant to me. I’m a fan of `Never` being a
bottom type for more reasons than just this. I also see no reason
why operator funcs couldn’t accept file and line as extra arguments
on the rhs.<br class=""></div>
</div>
<div style="font-family:Arial;" class=""><br class=""></div>
<div id="sig20055365" class="">
<div class="signature"><span class="font" style="font-family:arial, sans-serif, sans-serif">Best,</span><br class=""></div>
<div class="signature"><span class="font" style="font-family:arial, sans-serif, sans-serif"> Zachary
Waldowski</span><br class=""></div>
<div class="signature"><span class="font" style="font-family:arial, sans-serif, sans-serif"> </span><a href="mailto:zach@waldowski.me" class=""><span class="font" style="font-family:arial, sans-serif, sans-serif">zach@waldowski.me</span></a><br class="">
</div>
<div style="font-family:Arial;" class=""><br class=""></div>
<div style="font-family:Arial;" class="">On Tue, Jun 27, 2017, at
01:16 PM, Erica Sadun via swift-evolution wrote:<br class=""></div>
</div>
<blockquote type="cite" class="">
<div class="">Using an operator to provide feedback on the context
of a failed unwrap has become a commonly implemented approach in
the Swift developer Community. What are your thoughts about
adopting this widely-used operator into the standard
library?<br class=""></div>
<div class=""><br class=""></div>
<div class=""><span class="font" style="font-family:Menlo">guard
!lastItem.isEmpty else { return }</span><br class=""></div>
<div class=""><span class="font" style="font-family:Menlo">let
lastItem = array.last !! "Array must be non-empty"</span><br class=""></div>
<div class=""><br class=""></div>
<div class="">Details here: <a href="https://gist.github.com/erica/423e4b1c63b95c4c90338cdff4939a9b" class="">https://gist.github.com/erica/423e4b1c63b95c4c90338cdff4939a9b</a><br class="">
</div>
<div class=""><br class=""></div>
<div class="">Thank you for your thoughtful feedback, --
E<br class=""></div>
<div class=""><br class=""></div>
<div class=""><u class="">_______________________________________________</u><br class=""></div>
<div class="">swift-evolution mailing list<br class=""></div>
<div class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class=""></div>
<div class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a><br class="">
</div>
</blockquote>
<div style="font-family:Arial;" class=""><br class=""></div>
</div>
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</div>
</blockquote>
</div>
<br class=""></div>
</div>
</div>
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