<html><head><style>body{font-family:Helvetica,Arial;font-size:13px}</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><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_1490411525347686912" class="bloop_sign"></div> <br><p class="airmail_on">On March 24, 2017 at 10:11:07 PM, Xiaodi Wu (<a href="mailto:xiaodi.wu@gmail.com">xiaodi.wu@gmail.com</a>) wrote:</p> <div><blockquote type="cite" class="clean_bq" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px;"><span><div><span style="color: rgb(0, 0, 0); font-family: 'helvetica Neue', helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); float: none; display: inline !important;">I agree absolutely with those aims: very predictable performance, expressive and clean model, simplified learning and common cases. I'm arguing that the giant table of dispatch rules (see:<span class="Apple-converted-space"> </span></span><a href="http://raizlabscom-wpengine.netdna-ssl.com/dev/wp-content/uploads/sites/10/2016/12/Summary-3.png" style="font-family: 'helvetica Neue', helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">http://raizlabscom-wpengine.netdna-ssl.com/dev/wp-content/uploads/sites/10/2016/12/Summary-3.png</a><span style="color: rgb(0, 0, 0); font-family: 'helvetica Neue', helvetica; font-size: 14px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; background-color: rgb(255, 255, 255); float: none; display: inline !important;">) does not reach that goal.</span></div></span></blockquote></div><p>But clattner believes it does. This is clearer in his original, which is why I quoted it:</p><div><blockquote type="cite" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; padding-left: 5px; border-left-width: 1px !important; border-left-color: rgb(0, 64, 128) !important;"><span style="font-family: 'normal helvetica', sans-serif;">predictable performance model (someone writing a bootloader or firmware can stick to using Swift structs and have a simple guarantee of no dynamic overhead or runtime dependence)</span></blockquote></div><p>("predictable performance" to clattner means "value types are direct")</p><div><blockquote type="cite" style="font-family: Helvetica, Arial; font-size: 13px; font-style: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; border-top-width: 1px; border-right-width: 1px; border-bottom-width: 1px; padding-left: 5px; border-left-width: 1px !important; border-left-color: rgb(0, 64, 128) !important;">while also providing an expressive and clean high level programming model - simplifying learning and the common case where programmers don’t care to count cycles.</blockquote></div><p>("simplifying the learning" to clattner means that the programming model appears dynamic and the real performance characteristic is hidden.)</p><p>We know (because clattner told us here) what the design goal of Swift is with respect to static/dynamic dispatch. You may not agree with it, but that is another issue.</p><div></div><div></div><div></div></body></html>