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.send { color:#77bb77; }
.server { color:#7799bb; }
.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 can’t tell you the reason, but to me it feels like it’s doing the following thing:</p>
<pre><code>+ - - (Type: B) - - +
| |
| func bar() + - + (Type: A) - - + < - - - - - - - - - - - - - - - - - - - - +
| | | |
+ - - - - - - - + func output() + - + (Protocol: Foo) - - + — - self.bar() - + - (self as! B).bar() - +
| | | |
+ - - - - - - - + (default) func bar() | <- - - - - - - - +
| |
+ - - - - - - - - - - - - +
</code></pre>
<pre><code class="swift">class A:Foo {
func bar() {}
func output() {
print(type(of:self))
self.bar()
(self as! B).bar()
}
}
class B:A {
override func bar() {
print("I am B.")
}
}
</code></pre>
<p>Would solve this temporarily.</p>
<p>And there we are again with the same discussion if custom implementation of protocol members, which have default implementation, should have the <code>override</code> keyword or not.</p>
<p>Imagine your code like this (not valid code):</p>
<pre><code class="swift">protocol Foo {
func bar()
}
extension Foo {
func bar() {
print("I am bar.")
}
}
class A : Foo {
func output() {
print(type(of:self))
default.bar() // fallback an call directly the default implementation whenever needed
self.bar() // will print "I am bar." on A().output() but should print "I am B." if Self == B
(self as! B).bar()
}
}
class B : A {
override func bar() {
print("I am B.")
}
}
</code></pre>
<p>I still think default implementations should be called through something like <code>default.</code> + whenever you override a default implementation you’d need <code>override</code>. There is a discussion going on: <code>Mark protocol methods with their protocol</code>. I clearly did not solved your issue, but I might have wake your interest to participate. ;)</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_1474358089682738176" 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 20. September 2016 um 04:13:22, Zhao Xin via swift-users (<a href="mailto:swift-users@swift.org">swift-users@swift.org</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div><div></div><div>
<title></title>
<div dir="ltr">
<div class="gmail_default" style="font-family:georgia,serif">See
below code.</div>
<div class="gmail_default" style="font-family:georgia,serif">
<br></div>
<div class="gmail_default">
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(4,51,255)">
<span style="font-variant-ligatures:no-common-ligatures">protocol</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">Foo
{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">func</span>
<span style="font-variant-ligatures:no-common-ligatures">bar()</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;min-height:13px">
<br></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(4,51,255)">
<span style="font-variant-ligatures:no-common-ligatures">extension</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">Foo</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">func</span>
<span style="font-variant-ligatures:no-common-ligatures">bar()
{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(180,38,26)">
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">print</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">(</span><span style="font-variant-ligatures:no-common-ligatures">"I
am bar."</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">)</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;min-height:13px">
<br></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">class</span>
<span style="font-variant-ligatures:no-common-ligatures">A:</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">Foo</span>
<span style="font-variant-ligatures:no-common-ligatures">{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">func</span>
<span style="font-variant-ligatures:no-common-ligatures">output()
{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">print</span><span style="font-variant-ligatures:no-common-ligatures">(type(of:</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">self</span><span style="font-variant-ligatures:no-common-ligatures">))</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,0)">//
prints "B".</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(0,143,0)">
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">self</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">.</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">bar</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">()</span>
<span style="font-variant-ligatures:no-common-ligatures">// prints
"I am bar."</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
(self</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">as</span><span style="font-variant-ligatures:no-common-ligatures">!</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">B</span><span style="font-variant-ligatures:no-common-ligatures">).</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">bar</span><span style="font-variant-ligatures:no-common-ligatures">()</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,143,0)">//
prints "I am B."</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;min-height:13px">
<br></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">class</span>
<span style="font-variant-ligatures:no-common-ligatures">B:</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">A</span>
<span style="font-variant-ligatures:no-common-ligatures">{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">func</span>
<span style="font-variant-ligatures:no-common-ligatures">bar()
{</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
</span> <span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">print</span><span style="font-variant-ligatures:no-common-ligatures">(</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(180,38,26)">"I
am B."</span><span style="font-variant-ligatures:no-common-ligatures">)</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">
}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures">}</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;min-height:13px">
<br></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal">
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(4,51,255)">let</span>
<span style="font-variant-ligatures:no-common-ligatures">b =</span>
<span style="font-variant-ligatures:no-common-ligatures;color:rgb(52,149,175)">B</span><span style="font-variant-ligatures:no-common-ligatures">()</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(52,149,175)">
<span style="font-variant-ligatures:no-common-ligatures">b</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">.</span><span style="font-variant-ligatures:no-common-ligatures">output</span><span style="font-variant-ligatures:no-common-ligatures;color:rgb(0,0,0)">()</span></p>
<p style="font-family:menlo;margin:0px;font-size:11px;line-height:normal;color:rgb(52,149,175)">
<br></p>
<p style="margin:0px;line-height:normal"><font color="#000000" face="georgia, serif">I thought `self.bar()` would do the same as
`(self as! B).bar()`. It didn't. In my opinion,
`type(of:self) is B.type`, so they should be the same,
shouldn't they?</font></p>
<p style="margin:0px;line-height:normal"><font color="#000000" face="georgia, serif"><br></font></p>
<p style="margin:0px;line-height:normal"><font color="#000000" face="georgia, serif">Zhaoxin</font></p>
</div>
</div>
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