<div dir="ltr"><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Jul 18, 2016 at 12:28 PM, Johannes Neubauer via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Dear Xiaodi,<br>
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> Am 18.07.2016 um 20:55 schrieb Xiaodi Wu <<a href="mailto:xiaodi.wu@gmail.com">xiaodi.wu@gmail.com</a>>:<br>
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> As mentioned earlier, NaN != NaN, demonstrating that an Equatable instance that does not always equal itself is not "radical." Plainly, your proposal is unworkable.<br>
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</span>1. this is a basic internal type, so it can have a special behavior, since it is a well-designed data type created by the language designers (since there is no need to bootstrap swift from the first bits this is OK).<br></blockquote><div><br></div><div>The problem is that this is *exactly* how Swift works. There is nothing special about e.g. Double except for the fact that it wraps a built-in type and the implementation of its operations forward to built-in functions. This is how all the stdlib types work. You can build your own refcounted COW `Array` with exactly no additional compiler support from scratch, if you want.</div><div><br></div><div> </div><div><br></div><div><br></div><div> </div></div><br></div></div>