<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div><span></span></div><div><div><br><br>Sent from my iPad</div><div><br>On Jun 2, 2016, at 12:27 AM, Xiaodi Wu via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">On Thu, Jun 2, 2016 at 12:24 AM, Patrick Smith <span dir="ltr"><<a href="mailto:pgwsmith@gmail.com" target="_blank">pgwsmith@gmail.com</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div>I really like this idea. This IMO is lower level functionality than `type(of:)` (née dynamicType), so I think it makes sense for it to be grouped under its own domain, the MemoryLayout type.</div><div><br></div><div>Plus MemoryLayout can be extended with new convenience methods.</div><div><br></div><div>I’m fine with those old methods being removed, but I never use them so! Is it the same as calling type(of:) then using that with MemoryLayout? I imagine they could be fixit’d easily, and that they compile down to the same underlying code.</div></div></blockquote><div><br></div><div>I'm actually souring to the idea. It goes in the diametrically opposite direction from dynamicType. There, something was changed from being property-like to being function-like. Here, Dave's proposal would take something that's a function and turn it into a property. Hmm.</div></div></div></div></div></blockquote><div><br></div><div>That's not a fair comparison though. With dynamicType we removed a "magic" property visible on all types, which isn't something you can write and turned it into a function (which is obviously something you can write). </div><div><br></div><div>Dave's MemoryLayout creates a new type to bundle together related items which makes their semantic relationship more clear. It also receives the type via a generic argument rather than a function argument and makes the properties static. That is more representative of what is actually happening and could help to prevent confusion. </div><div><br></div><div>If we really need an 'ofValue' option that infers T from a value the properties on MemoryLayout could also be made available as instance properties and it could have an initializer that accepts an instance to T and throws the value away. However, I'm not at all convinced this is necessary.</div><br><blockquote type="cite"><div><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><span class=""><div><blockquote type="cite"><div>On 2 Jun 2016, at 3:05 PM, Xiaodi Wu via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div><br><div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">2. Dave A. and others expressed the opinion that these should probably not be global functions; his preference was for:</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">```</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">MemoryLayout<T>.size // currently sizeof()</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">MemoryLayout<T>.spacing // currently strideof()</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">MemoryLayout<T>.alignment // currently alignof()</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">```</div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div><div class="gmail_extra" style="font-family:Helvetica;font-size:12px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">3. Dave A. proposed that sizeofValue(), strideofValue(), and alignofValue() are better off removed altogether. I don't know if people are going to be happy about this idea.</div></div></blockquote></div><br></span></div></blockquote></div><br></div></div>
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