<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">I have been writing code in a style that uses explicit effect handling lately. In this style of code, a request describing an async task is returned from a function and later interpreted by a library. When the task completes the library passes the result to completion handler that is part of the task description (which produces subsequent effects to interpret). </div><div class=""><br class=""></div><div class="">It isn’t possible to express the completion handlers attached to task descriptions as an async call. The function needs to return the task description immediately. For this reason, I believe it will be necessary to continue using a Result type in code written in this style even after async / await is introduced.</div><br class=""><div><blockquote type="cite" class=""><div class="">On Nov 2, 2017, at 1:53 PM, Dan Stenmark 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=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">With the upcoming async-await constructs supporting do-try-catch natively, what would the use-case for an explicit Result type be?</div><div class=""><br class=""></div><div class="">Dan</div><br class=""><div class=""><blockquote type="cite" class=""><div class="">On Nov 2, 2017, at 11:08 AM, Jon Shier 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=""><meta http-equiv="Content-Type" content="text/html; charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;" class="">Swift-Evolution:<div class=""><span class="Apple-tab-span" style="white-space:pre"> </span>I’ve written a first draft of a proposal to add Result<T> to the standard library by directly porting the Result<T> type used in Alamofire to the standard library. I’d be happy to implement it (type and tests for free!) if someone could point me to the right place to do so. I’m not including it directly in this email, since it includes the full implementation and is therefore quite long. (Discourse, please!) </div><div class=""><br class=""></div><div class=""><a href="https://github.com/jshier/swift-evolution/blob/master/proposals/0187-add-result-to-the-standard-library.md" class="">https://github.com/jshier/swift-evolution/blob/master/proposals/0187-add-result-to-the-standard-library.md</a></div><div class=""><br class=""></div><div class=""><br class=""></div><div class="">Thanks, </div><div class=""><br class=""></div><div class="">Jon Shier</div><div class=""><br class=""></div><div class=""><br class=""></div></div>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br 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><br class=""></div>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></div></blockquote></div><br class=""></body></html>