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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>I’ve already mentioned this in this thread. This is one of the missing features from the generics manifesto, however it’s (almost) a syntactic sugar only. It means that if we would enforce <code>default</code> in Swift 4, then having default implementation directly inside protocols would be really a syntactic and additional change only, which is a good sign. ;)</p>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1497640625449387008" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 16. Juni 2017 um 20:39:21, Tino Heth via swift-evolution (<a href="mailto:swift-evolution@swift.org">swift-evolution@swift.org</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div></div><div>
<title></title>
The described problem might be one of the most famous itches of the
language, but imho the bar for new keywords* should be higher than
that — and there are alternatives:
<div class=""><br class=""></div>
<div class="">First, I guess many would like to see this to be
valid Swift:</div>
<div class=""><br class=""></div>
<div class="">
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(186, 45, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">protocol</span> <span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">Foo {</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span> <span style="font-variant-ligatures: no-common-ligatures" class="">bar()
{</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">print(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"Default
implementation called"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
</div>
<div class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div>
<div class="">It's the most convenient way of avoiding typos: avoid
to type ;-)</div>
<div class="">Imho this might already be enough, but for a full
alternative for "default", I'd suggest something like this:</div>
<div class=""><br class=""></div>
<div class="">
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(186, 45, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">extension</span> <span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">Foo</span> <span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">{</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span> <span style="font-variant-ligatures: no-common-ligatures" class="">Foo.bar()
{</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">print(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"String has
its own implementation"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
</div>
<div class=""><br class=""></div>
<div class="">(to make it more familiar for those with a C++
background, "Foo::bar" could be used instead ;-)</div>
<div class=""><br class=""></div>
<div class="">Additional benefit: This wouldn't be limited to
protocols — and it could possibly help in weird situations when two
protocols declare functions with identical signature...</div>
<div class=""><br class=""></div>
<div class="">
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(186, 45, 162);" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">extension</span> <span style="font-variant-ligatures: no-common-ligatures; color: #703daa" class="">String</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">:</span> <span style="font-variant-ligatures: no-common-ligatures; color: #4f8187" class="">Foo</span> <span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">{</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #ba2da2" class="">func</span> <span style="font-variant-ligatures: no-common-ligatures" class="">Foo.bar()
{</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo; color: rgb(209, 47, 27);" class=""><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">print(</span><span style="font-variant-ligatures: no-common-ligatures" class="">"String has
its own implementation"</span><span style="font-variant-ligatures: no-common-ligatures; color: #000000" class="">)</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">func Foo.barr() {</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// compiler error, Foo defines no function
"barr"</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class=""><br class=""></span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">func barr() {</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">// this is fine, no connection to a protocol</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
<div style="margin: 0px; font-size: 11px; line-height: normal; font-family: Menlo;" class=""><span style="font-variant-ligatures: no-common-ligatures" class="">}</span></div>
</div>
<div class=""><br class=""></div>
<div class="">- Tino</div>
<div class=""><br class=""></div>
<div class="">* well, I guess "default" is not really a new
keyword… but you get the point</div>
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