<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="">If your function returns an Int? then there’s a reason for that and nil will mean something. And if your function can throw or return an Int? there will also be a very good reason for that and nil will also meaning something. If you then choose to use try? Swift has to return a double Optional because otherwise it would hide information from you. The outer Optional tells you whether there was an error and the inner Optional represents the return value of the function.</div><div class=""><br class=""></div><div class="">But to answer your question: If I’m not mistaken, there is no way to make try? unwrap the optional result of a function in case of success.</div><div class=""><br class=""></div><div class="">Is the function you’re calling one that you wrote? If so, I would try to find a way to make it return a non-optional Int. Maybe the case where it would return nil could be modeled as throwing an error?</div><div class=""><br class=""></div><div class="">Cheers,</div><div class=""><br class=""></div><div class="">Marco</div><div class=""><br class=""></div><br class=""><div><blockquote type="cite" class=""><div class="">On 2016-01-25, at 14:01, Jonathan Bailey via swift-users <<a href="mailto:swift-users@swift.org" class="">swift-users@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="">In the language guide on the apple website, <a href="https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/ErrorHandling.html#//apple_ref/doc/uid/TP40014097-CH42-ID542" class="">https://developer.apple.com/library/ios/documentation/Swift/Conceptual/Swift_Programming_Language/ErrorHandling.html#//apple_ref/doc/uid/TP40014097-CH42-ID542</a><div class=""><br class=""></div><div class="">It says the following assignments to x and y are equivalent:</div><div class=""><ol class="code-lines" style="border: 0px; font-size: 14px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; counter-reset: li 0; line-height: 1.6em; list-style: none; font-family: Helvetica, Arial, sans-serif;"><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">func</span> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">someThrowingFunction</span>() <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">throws</span> -> <span class="n" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(92, 38, 153);">Int</span> { ... }</code></li></ol></div><ol class="code-lines" style="border: 0px; font-size: 14px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; counter-reset: li 0; line-height: 1.6em; list-style: none; font-family: Helvetica, Arial, sans-serif;"><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">let</span> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">x</span> = <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">try</span>? <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">someThrowingFunction</span>()</code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="c" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(0, 131, 18);">// x has type `Int?`</span></code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><span style="font-family: Menlo, monospace; font-size: 0.85em;" class=""> </span></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">let</span> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">y</span>: <span class="n" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(92, 38, 153);">Int</span>?</code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">do</span> {</code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">y</span> = <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">try</span> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">someThrowingFunction</span>()</code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -17px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;">} <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">catch</span> {</code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -17px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">y</span> = <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">nil</span></code></li><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -17px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;">}</code></li></ol><div style="text-indent: -17px;" class=""><span style="text-indent: 0px;" class=""><br class=""></span></div><div style="text-indent: -17px;" class=""><span style="text-indent: 0px;" class="">However this isn’t the case if someThrowingFunction also returns an optional, say:</span></div><div style="text-indent: -17px;" class=""><span style="text-indent: 0px;" class=""><br class=""></span></div><div class=""><ol class="code-lines" style="border: 0px; font-size: 14px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; counter-reset: li 0; line-height: 1.6em; list-style: none; font-family: Helvetica, Arial, sans-serif;"><li style="border-width: 0px 0px 0px 18px; border-left-style: solid; border-left-color: transparent; margin: 0px; outline: 0px; padding: 0px 10px 0px 0px; vertical-align: baseline; text-indent: -13px; white-space: pre-wrap; list-style-type: none;" class=""><code class="code-voice" style="border: 0px; font-size: 0.85em; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; font-family: Menlo, monospace; word-wrap: break-word;"><span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">func</span> <span class="vc" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(63, 110, 116);">someThrowingFunction</span>() <span class="kt" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(170, 51, 145);">throws</span> -> <span class="n" style="border: 0px; margin: 0px; outline: 0px; padding: 0px; vertical-align: baseline; color: rgb(92, 38, 153);">Int?</span> { ... }</code></li></ol><div style="text-indent: -13px;" class=""><font face="Menlo, monospace" class=""><span style="white-space: pre-wrap;" class=""><br class=""></span></font></div></div><div style="text-indent: -13px;" class=""><span style="text-indent: 0px;" class="">The type of x would be `Int??`, but the type of y is still `Int?`, is there some way to make the `try?` return an `Int?` instead of a double optional, which is not very helpful.</span></div><div style="text-indent: -13px;" class=""><span style="text-indent: 0px;" class=""><br class=""></span></div><div style="text-indent: -13px;" class=""><span style="text-indent: 0px;" class="">Thanks,</span></div><div style="text-indent: -13px;" class=""><span style="text-indent: 0px;" class="">Jonathan</span></div><div class=""><br class=""></div></div>_______________________________________________<br class="">swift-users mailing list<br class=""><a href="mailto:swift-users@swift.org" class="">swift-users@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-users<br class=""></div></blockquote></div><br class=""></body></html>