<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="">Excuse me if this has been mentioned already. I just subscribed to this list and don’t know anything about how to use it.<div class=""><br class=""></div><div class="">It seems to me that there is a third choice for parameter names, which has yet to be explored. The way protocols are implemented now can educate us about it:</div><div class=""><br class=""></div><div class=""><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">protocol</span> Protocol {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// This argument label does nothing, </div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// but is required for compilation.</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(int: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>)</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class="">}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; min-height: 16px;" class=""><br class=""></div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class="">// This compiles.</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span> Struct: <span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">Protocol</span> {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(not_int_atAll: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>) {}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class="">}</div><div class=""><br class=""></div><div class="">Because internal parameter names in protocol names do nothing, they should not be required:</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">protocol</span> Protocol {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(<span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>)</div><div class=""><span style="font-family: Menlo; font-size: 14px;" class="">}</span></div><div class=""><br class=""></div><div class="">This inspires the following syntax:</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span> Struct: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Protocol</span> {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(<span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>) {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// The parameter is called $0 here</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> }</div><div class=""><span style="font-family: Menlo; font-size: 14px;" class="">}</span></div><div class=""><br class=""></div><div class="">This kind of thing is sorely needed for operators, which use the standards “lhs” and “rhs” despite no hands being involved.</div><div class=""><br class=""></div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span> Struct: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Protocol</span> {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// Should also be valid;</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// but we should explicitly have to </div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// opt out of external naming.</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(<span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">_</span> int: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>) {}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class="">}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span> Struct: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Protocol</span> {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// Should not be valid;</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// int is now the external parameter name</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(int: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>) {}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class="">}</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">struct</span> Struct: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Protocol</span> {</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo; color: rgb(0, 132, 0);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class=""> </span>// Should not be valid.</div><div style="margin: 0px; font-size: 14px; line-height: normal; font-family: Menlo;" class=""> <span style="font-variant-ligatures: no-common-ligatures; color: #bb2ca2" class="">func</span> function(preposition int: <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">Int</span>) {}</div><div class=""><span style="font-family: Menlo; font-size: 14px;" class="">}</span> </div><div class=""><br class=""></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On Jan 21, 2016, at 5:04 PM, Joe Groff 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=""><div style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><blockquote type="cite" class=""><div class=""><br class="Apple-interchange-newline">On Jan 21, 2016, at 1:58 PM, John McCall 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=""><div class=""><blockquote type="cite" class="">On Jan 21, 2016, at 12:33 PM, Charles Constant via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:<br class=""><blockquote type="cite" class="">say("hello")<br class=""><br class="">is a big improvement, which IMO perfectly illustrates why we want the<br class="">default as it is.<br class=""></blockquote><br class="">Maybe so, but there just has to be some way to do this that doesn't bake the design into the entirety of the Swift language. Is there some way Apple could implement this that only affects Swift imports/exports with Obj-C?<br class=""></blockquote><br class="">You’re repeating your assumption here that the current design was reached by necessity for ObjC importing. That is not the case. As has been said multiple times in this very thread, we looked at a lot of existing APIs — and of course those APIs included ObjC APIs, but not exclusively by any stretch — and decided that, far more often than not, the first argument of a function/method is a “direct object” whose relationship to the operation is obvious and does not benefit from labelling. We strongly considered adopting the rule that all arguments should be labelled by default, and we decided that, on balance, it led to a lot of really useless labels. It’s a very simple and understandable language rule, but it leads to worse results when you actually apply to it to real code. There are, of course, exceptions, but there would have been in any case.<br class=""><br class="">But like Dave said, we’re about to have a major conversation about this, and you are welcome to participate.<br class=""></div></div></blockquote></div><br class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><div class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">One thing to consider is, if you follow either Cocoa's contemporary naming conventions or the proposed Swift 3 naming conventions, then the labels you end up with for secondary arguments frequently aren't good binding names, so the conventions steer you toward providing an explicit binding name:</div><div class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class=""></div><blockquote class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 0px 0px 40px; border: none; padding: 0px;"><div class="">// Classic Cocoa style</div><div class="">func doStuff(stuff: Stuff, involvingThing thing: Thing) { ... }</div></blockquote><blockquote class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; margin: 0px 0px 0px 40px; border: none; padding: 0px;"><div class="">// Swift 3 style</div><div class="">func do(stuff: Stuff, involving thing: Thing) { ... }</div><div class=""><br class=""></div></blockquote><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">We could make the language rules more consistent, while still encouraging people to follow the naming guidelines, by *requiring* every argument after the first to specify both an argument label (or explicit '_') and binding name. That makes the naive 'min(x: Int, y: Int)' case an error we can provide an easy fixit for.</span><div class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;"><br class=""></div><div class="" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;">-Joe</div><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">_______________________________________________</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><span style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; float: none; display: inline !important;" class="">swift-evolution mailing list</span><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="mailto:swift-evolution@swift.org" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">swift-evolution@swift.org</a><br style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class=""><a href="https://lists.swift.org/mailman/listinfo/swift-evolution" style="font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px;" class="">https://lists.swift.org/mailman/listinfo/swift-evolution</a></div></blockquote></div><br class=""></div></div></body></html>