<div dir="ltr"><div><div>I agree with this, extensions on types defined in the same file are generally silly, and default implementations belong in the protocol body. I don’t agree with certain style guides prescription of same-file extensions; they should only be used to hide protocol conformances that are “unimportant” to the functionality of the type. In practice this means only conformances like <span style="font-family:monospace,monospace">CustomStringConvertible</span> and <span style="font-family:monospace,monospace">CustomDebugStringConvertible</span> live in extensions.<br><br></div>If you want to group related methods, use linebreaks and whitespace for that. Don’t split up the type braces since that messes up the whole one-set-of-braces == one type definition visual rule.<br><br></div>The only time it ever makes sense to extend a non concrete type that you own is when adding conditional default implementations. Having to extend a bare protocol is the product of a language limitation.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Aug 2, 2017 at 6:26 AM, Tino Heth via swift-evolution <span dir="ltr"><<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><div><span class=""><br><blockquote type="cite"><div><span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">That would work as well, but it has the downside of forcing a potentially huge number of methods to be implemented in a single place, reducing the readability as opposed to packing them into semantically related groups in the form of extensions.</span><br style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"></div></blockquote></span><div>I really don't get why people are so obsessed with same-file extensions:<div>They are recommended in style guides, influencers blog about them, and they motivated a ridiculous complex change in the access rights system. Yet I haven't seen any evidence that they offer real benefit.</div><div>Extensions are great for adding useful helpers to existing types, and still allow you to selectively expose details of your own classes — but most people seem to ignore those options and focus on something can be done better with plain old comments.</div><div>[sorry for the rant — but I think a critical look at extensions is long overdue: I rarely see someone questioning their role, so basically, we are making important decisions based on pure superstition]</div><div><br></div><div>A protocol itself is already a vehicle to group related methods, and if you have a huge entity, it doesn't get better just because you split it and hide its complexity.</div></div><span class=""><br><blockquote type="cite"><div><span style="font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px;float:none;display:inline!important">Also, please include the original message for reference purposes.</span></div></blockquote></span></div>[hopes Discourse will happen soon ;-) ]</div><br>______________________________<wbr>_________________<br>
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