<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div></div><blockquote type="cite"><span style="color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);">The review of SE-0142: "Permit where clauses to constrain associated types" begins now and runs through September 30, 2016. The proposal is available here:</span><br><blockquote style="box-sizing: border-box; margin: 0px 0px 16px; padding: 0px 1em; border-left-width: 0.25em; border-left-style: solid; border-left-color: rgb(221, 221, 221); background-color: rgb(255, 255, 255);" class=""><div style="box-sizing: border-box; margin-top: 0px; margin-bottom: 0px;" class=""><font color="#777777" face="-apple-system, BlinkMacSystemFont, Segoe UI, Roboto, Helvetica, Arial, sans-serif, Apple Color Emoji, Segoe UI Emoji, Segoe UI Symbol" size="3" class=""><a href="https://github.com/apple/swift-evolution/blob/master/proposals/0142-associated-types-constraints.md" class="">https://github.com/apple/swift-evolution/blob/master/proposals/0142-associated-types-constraints.md</a></font></div></blockquote></blockquote><br><blockquote type="cite"><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box;" class="">What is your evaluation of the proposal?</li></ul></blockquote>It is a valuable addition to Swift and certainly something I have desired. However I feel the proposed syntax is long winded, something associated types already suffer from. There also seems to be an inconsistency in specifying constraints sometimes in where clauses and other times as a constraint on the associated type. <div><br><blockquote type="cite"><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Is the problem being addressed significant enough to warrant a change to Swift?</li></ul></blockquote>Yes</div><div><br><blockquote type="cite"><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Does this proposal fit well with the feel and direction of Swift?</li></ul></blockquote>Not quite. See above. </div><div><br><blockquote type="cite"><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">If you have used other languages or libraries with a similar feature, how do you feel that this proposal compares to those?</li></ul></blockquote>It is similar to generics and begs the question why not abandon associated types and just have generics on protocols. </div><div><br><blockquote type="cite"><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(51, 51, 51); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box; margin-top: 0.25em;" class="">How much effort did you put into your review? A glance, a quick reading, or an in-depth study?</li></ul></blockquote>Mainly my comments are based on writing my own collection library in Swift and comparing that exercise to similar in Java and C++. It is at the moment significantly harder than in Java but easier than C++. Any improvement in associated types would be welcome. <br></div></body></html>