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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>Access control modifier: <code>public > internal == /* implicitly internal */ > fileprivate >= private</code></p>
<pre><code class="swift">//===== TOPLEVEL / File - Scope
//===== some protocols
public protocol A {
func aa()
}
private protocol B {
func bb()
}
fileprivate protocol C {
func cc()
}
internal protocol D {
func dd()
}
/* implicitly internal */ protocol E {
func ee()
}
//===== some types
public struct FF {}
private struct GG {}
fileprivate struct HH {}
internal struct II {}
/* implicitly internal */ struct JJ {}
//===== some extensions
// We should be able to extend it with all protocols: A, B, C, D, E
// BUT it depends whether all protocols are visible at this scope
// In this example they are visible!
//
// The compiler should force you to write modifier for: A, B and C
// `internal` is always optional
public extension FF: A, B, C, D, E {
public func aa()
// Visible in this scope only
private func bb()
// Visible in this file
fileprivate func cc()
// Visible for the whole module
// We do not need to write out `internal` here
/* implicitly internal */ func dd()
// visible for the whole module
/* implicitly internal */ func ee()
}
// At top-level `private` is like `fileprivate`
private extension FF: A, B, C, D, E {
// Same as in `public extension`
// Except everything is `private` (or `fileprivate`)
}
fileprivate extension FF: A, B, C, D, E {
// Same as in `public extension`
// Except everything is `fileprivate`
}
internal extension FF: A, B, C, D, E {
// Same as in `public extension`
// Except everything is `internal` or explicitly `private` or `fileprivate`
}
/* implicitly internal */ extension FF: A, B, C, D, E {
// Same as in `internal extension`
}
// For GG, HH, II and JJ we cannot extend these types with a `public` modifier!
// GG and HH can't be extended with `internal` modifier
</code></pre>
<p>If I missed anything, please let me know.</p>
<p>Protocols should not import an access modifier on their members, because this is a documented rule that we use the modifier from protocols definition.</p>
<pre><code class="swift">public protocol A {
var someMember: Type {}
}
// SHOULD NOT LOOK LIKE THIS:
public protocol A {
public var someMember: Type {}
}
// CORRECT VERSION:
public protocol A {
var someMember: Type {}
}
</code></pre>
<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_1466411899522876928" 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. Juni 2016 um 10:35:59, 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>Everyone does feel comfortable with <code>implicit public
extensions</code>?</p>
</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_1466411689134916096" 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 19. Juni 2016 um 09:18:35, Adrian Zubarev
(<a href="mailto:adrian.zubarev@devandartist.com">adrian.zubarev@devandartist.com</a>)
schrieb:</p>
<blockquote type="cite" class="clean_bq">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">
<div>
<div class="bloop_markdown">
<p><span>One problem I found with the mentioned suggestion of mine
is this:</span></p>
<pre><span><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></span></pre>
<ul>
<li><span>Why is that like this?</span></li>
<li><span>Can this be fixed?</span></li>
<li><span>Implicit public <code>extension</code> feels odd and is
inconsistent if you ask me.</span></li>
</ul>
<p><span>Any statement to the pitched suggestion?</span></p>
</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;">
<span><br></span></div>
<span><br></span>
<div id="bloop_sign_1466320413381489920" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
<span>-- <br>
Adrian Zubarev<br>
Sent with Airmail</span></div>
</div>
<span><br></span>
<p class="airmail_on"><span>Am 17. Juni 2016 um 11:28:18, Adrian
Zubarev (<a href="mailto:adrian.zubarev@devandartist.com">adrian.zubarev@devandartist.com</a>)
schrieb:</span></p>
<blockquote type="cite" class="clean_bq">
<div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">
<div>
<div class="bloop_markdown">
<p><span><span>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).</span></span></p>
<ul>
<li>
<p><span>Why are extensions not marked as <code>public</code> in
public apis when the module is imported?</span></p>
<blockquote>
<p><span>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.</span></p>
<p><span>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.</span></p>
<p><span>Source: Apple Inc. The Swift Programming Language (Swift
2.2).</span></p>
</blockquote>
<ul>
<li><span>This does not tell us how the access control modifier
works on extensions. Here are three examples:</span></li>
</ul>
<pre><span><code class="swift">public struct A {}
/* implicitly internal */ extension A {}
// This extension won't be exported
</code></span></pre>
<ul>
<li><span>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>:</span></li>
</ul>
<pre><span><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></span></pre>
<p><span>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>.</span></p>
<pre><span><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></span></pre>
<p><span>Extensions seem to behave differently and its behaviors is
inconsistent and not documented.</span></p>
</li>
<li>
<p><span>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.</span></p>
<pre><span><code class="swift">public protocol D {
func doSomething()
}
</code></span></pre>
<p><span>Protocol <code>D</code> will be exported as:</span></p>
<pre><span><code class="swift">public protocol D {
public func doSomething()
}
</code></span></pre></li>
</ul>
<p><span>Here is my suggestion:</span></p>
<ul>
<li>
<p><span>Fix the behavior for extensions and document it
correctly:</span></p>
<pre><span><code class="swift">public struct B {}
/* implicitly public */ extension B {
public func foo() {}
/* implicitly internal */ func boo() {}
}
</code></span></pre>
<ul>
<li><span>Such an <code>extension</code> should not be implicitly
public and behave like other types and stay implicitly
<code>internal</code>.</span></li>
<li><span>The compiler should provide a warning for the
<code>foo()</code> function: <code>Declaring a public function for
an internal type</code></span></li>
<li><span>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.</span></li>
<li><span><strong>This inconsistent behavior is source breaking and
I’d suggest this change to happen in Swift 3!</strong></span></li>
</ul>
</li>
<li>
<p><span>Remove <code>public</code> modifier from imported
protocols OR document this behavior correctly!</span></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;">
<span><br></span></div>
<span><br></span>
<div id="bloop_sign_1466150541337204992" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
<span>-- <br>
Adrian Zubarev<br>
Sent with Airmail</span></div>
</div>
</div>
<div class="bloop_markdown"></div>
</div>
</div>
</blockquote>
</div>
<div class="bloop_markdown"></div>
</div>
</div>
</blockquote>
</div>
<div class="bloop_markdown"></div>
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