<div dir="ltr">I have the same thoughts and also have code that configures itself on delegate setting.</div><br><div class="gmail_quote"><div dir="ltr">On Fri, Apr 22, 2016 at 10:04 AM David Waite via swift-evolution <<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">Sure, but I personally want to configure delegates early, when the delegate is set.<div><br></div><div>It may be inappropriate to send a synthetic message through (e.g. give me the table row height for arbitrary index -1 so I can detect if you have overridden behavior)</div><div><br></div><div>A default implementation may help the caller, but some API do consider a non-default implementation to be a flag in itself.</div><div><br></div><div>I don’t think you can meet current objective-c usage and meaning of optional protocols by collapsing the flag into default method behavior. This would cause problems when porting the objective-c caller of the delegate interface to swift.</div></div><div style="word-wrap:break-word"><div><br></div><div>-DW</div></div><div style="word-wrap:break-word"><div><br><div><blockquote type="cite"><div>On Apr 22, 2016, at 10:01 AM, Thorsten Seitz <<a href="mailto:tseitz42@icloud.com" target="_blank">tseitz42@icloud.com</a>> wrote:</div><br><div><div 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">We could require optional methods which would return T to instead return OptionalResult<T> which is essentially an enum with values 'unimplemented' and 'implemented(T)', i.e. essentially the same as Optional but as a separate type to avoid confusion when the real result would be 'T?'.</div><div 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 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">Default implementations would answer 'unimplemented'.</div><div 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 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">This would require the caller to handle the unimplemented default case explicitly.</div><div 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 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">-Thorsten </div></div></blockquote></div><br></div></div>_______________________________________________<br>
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