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.send { color:#77bb77; }
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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>One problem I found with the mentioned suggestion of mine is this:</p>
<pre><code class="swift">public protocol A {}
public class B {}
// 'public' modifier cannot be used with
// extensions that declare protocol conformances
public extension B: A {}
</code></pre>
<ul>
<li>Why is that like this?</li>
<li>Can this be fixed?</li>
<li>Implicit public <code>extension</code> feels odd and is inconsistent if you ask me.</li>
</ul>
<p>Any statement to the pitched suggestion?</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_1466320413381489920" 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 17. Juni 2016 um 11:28:18, Adrian Zubarev (<a href="mailto:adrian.zubarev@devandartist.com">adrian.zubarev@devandartist.com</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;"><div></div><div>
<title></title>
<div class="bloop_markdown">
<p>I’ve spotted some inconsistency on access control modifier I’d
like to discuss in this thread (the behavior is not groundbreaking
but inconsistent from readers and developers view perspective).</p>
<ul>
<li>
<p>Why are extensions not marked as <code>public</code> in public
apis when the module is imported?</p>
<blockquote>
<p>Any type members added in an extension have the same default
access level as type members declared in the original type being
extended. If you extend a public or internal type, any new type
members you add will have a default access level of internal. If
you extend a private type, any new type members you add will have a
default access level of private.</p>
<p>Alternatively, you can mark an extension with an explicit access
level modifier (for example, private extension) to set a new
default access level for all members defined within the extension.
This new default can still be overridden within the extension for
individual type members.</p>
<p>Source: Apple Inc. The Swift Programming Language (Swift
2.2).</p>
</blockquote>
<ul>
<li>This does not tell us how the access control modifier works on
extensions. Here are three examples:</li>
</ul>
<pre><code class="swift">public struct A {}
/* implicitly internal */ extension A {}
// This extension won't be exported
</code></pre>
<ul>
<li>as soon as at least one member modifier of an extension is
<code>public</code> (if the extended type allows that and is also
<code>public</code>), the extension itself becomes implicitly
<code>public</code>:</li>
</ul>
<pre><code class="swift">public struct B {}
/* implicitly public */ extension B {
public func foo() {}
/* implicitly internal */ func boo() {}
}
// This extension will be exported as
extension B {
public func foo()
}
</code></pre>
<p>This is inconsistent to other types, because you can not leave
out the modifier for instance on classes, then add a public member
and assume that your class is implicitly <code>public</code>! The
compiler knows that and provides a correct warning that the
mentioned class is <code>internal</code>.</p>
<pre><code class="swift">public struct C {}
public extension C {
public func foo() {}
/* implicitly internal */ func boo() {}
}
// This extension will be exported as
/* public is missing here */ extension C {
public func foo()
}
</code></pre>
<p>Extensions seem to behave differently and its behaviors is
inconsistent and not documented.</p>
</li>
<li>
<p>protocols has explicit <code>public</code> modifier on its
members when the module is imported. However, <code>'public'
modifier cannot be used in protocols</code> is how the compiler
treat modifiers in protocols on declaration.</p>
<pre><code class="swift">public protocol D {
func doSomething()
}
</code></pre>
<p>Protocol <code>D</code> will be exported as:</p>
<pre><code class="swift">public protocol D {
public func doSomething()
}
</code></pre></li>
</ul>
<p>Here is my suggestion:</p>
<ul>
<li>
<p>Fix the behavior for extensions and document it correctly:</p>
<pre><code class="swift">public struct B {}
/* implicitly public */ extension B {
public func foo() {}
/* implicitly internal */ func boo() {}
}
</code></pre>
<ul>
<li>Such an <code>extension</code> should not be implicitly public
and behave like other types and stay implicitly
<code>internal</code>.</li>
<li>The compiler should provide a warning for the
<code>foo()</code> function: <code>Declaring a public function for
an internal type</code></li>
<li>Extensions should have explicit <code>public</code> modifier
like other types if the <code>extension</code> was marked as
<code>public</code> and was imported into an other
project/module.</li>
<li><strong>This inconsistent behavior is source breaking and I’d
suggest this change to happen in Swift 3!</strong></li>
</ul>
</li>
<li>
<p>Remove <code>public</code> modifier from imported protocols OR
document this behavior correctly!</p>
</li>
</ul>
</div>
<div class="bloop_original_html">
<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_1466150541337204992" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
-- <br>
Adrian Zubarev<br>
Sent with Airmail</div>
</div>
</div>
<div class="bloop_markdown"></div>
</div></div></span></blockquote></div><div class="bloop_markdown"><p></p></div></body></html>