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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>The proposal I was just talking about is this one here: <a href="https://github.com/DevAndArtist/swift-evolution/blob/classes_in_any_existential/proposals/nnnn-classes-in-any-existential.md">https://github.com/DevAndArtist/swift-evolution/blob/classes_in_any_existential/proposals/nnnn-classes-in-any-existential.md</a></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_1464161944244001024" 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 25. Mai 2016 bei 09:38:29, 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>
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<p>I’ll read closely all the feedback we’ve got here so far and
comment when I’m done with my work today.</p>
<p>Here is the <em>future direction</em> part from the other
proposal we haven’t submitted yet, where I believe Joe mentioned a
few words in that direction:</p>
<h2 id="futuredirections">Future directions</h2>
<ul>
<li>
<p><code>any<...></code> should reflect powerful generalized
generic features to be able to constrain types even further (e.g.
<code>where</code> clause).</p>
</li>
<li>
<p>Adding constraints for other extendable types like
<code>struct</code> and <code>enum</code> and generalize these.
This will allow us to form more typealiases like:</p>
<pre><code class="swift">typealias AnyStruct = any<struct>
typealias AnyEnum = any<enum>
</code>
</pre>
<ul>
<li>Example:</li>
</ul>
<pre><code class="swift">protocol A { func boo() }
// Structs that conforms to a specific protocol.
func foo(value: any<struct, SomeProtocol>)
func foo(value: any<AnyStruct, SomeProtocol>)
// Enums that conforms to a specific protocol.
func foo(value: any<enum, SomeProtocol>)
func foo(value: any<AnyEnum, SomeProtocol>)
// Lets say this array is filled with structs, classes and enums,
// which all conforms to `SomeProtocol`.
let array: [SomeProtocol] = // fill
// Filter these types:
var classArray: [any<class, SomeProtocol>] = array.flatMap { $0 as? any<class, SomeProtocol> }
var structArray: [any<struct, SomeProtocol>] = array.flatMap { $0 as? any<struct, SomeProtocol> }
var enumArray: [any<enum, SomeProtocol>] = array.flatMap { $0 as? any<enum, SomeProtocol> }
</code>
</pre></li>
</ul>
<p>Flattened operators or even <code>Type operators</code> for
<code>any<...></code>:</p>
<pre><code class="swift">class B {
var mainView: UIView & SomeProtocol
init(view: UIView & SomeProtocol) {
self. mainView = view
}
}
</code>
</pre>
<blockquote>
<p>The <code>&</code> type operator would produce a “flattened"
<code>any<></code> with its operands. It could be overloaded
to accept either a concrete type or a protocol on the lhs and would
produce <code>Type</code> for an lhs that is a type and
<code>any<...></code> when lhs is a protocol. <code>Type
operators</code> would be evaluated during compile time and would
produce a type that is used where the expression was present in the
code. This is a long-term idea, not something that needs to be
considered right now.</p>
<p>Written by: <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160509/017499.html">
Matthew Johnson</a></p>
</blockquote>
<p>Adding <code>one<...></code> which can reduce overloading
(idea provided by: <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160509/017397.html">
Thorsten Seitz</a>). <code>one<...></code> will pick the
first type match from within the angle brackets to the dynamic type
at compile time and proceed. One would then need to handle the
value by own desire.</p>
<pre><code class="swift">func foo(value: one<String, Int>) {
if let v = value as? String {
// Do some work
} else if let v = value as? Int {
// Do some work
}
}
// Flattened version:
func foo(value: String | Int)
</code>
</pre>
<p>Mix <code>any<...></code> and
<code>one<...></code>:</p>
<pre><code class="swift">// Accept only types constrained by
// (`ClassA` AND `SomeProtocol`) OR (`ClassB` AND `SomeProtocol`)
func foo(value: any<one<ClassA, ClassB>, SomeProtocol>)
// Flattened version:
func foo(value: (ClassA | ClassB) & SomeProtocol)
</code>
</pre>
<p>Typealias <code>AnyValue</code> (for extendable types only):</p>
<pre><code class="swift">// Isn't this like magic
typealias AnyValue = one<any<struct>, any<enum>>
typealias AnyValue = one<AnyStruct, AnyEnum>
typealias AnyValue = any<struct> | any<enum>
typealias AnyValue = AnyStruct | AnyEnum
// Any value which conforms to `SomeProtocol`.
// Reference types are finally out the way.
func foo(value: any<AnyValue, SomeProtocol>)
// Flattened version:
func foo(value: AnyValue & SomeProtocol)
</code>
</pre>
<p>————</p>
<p><code>one<…></code> is a different story, so don’t stick
with it too much in this discussion.</p>
<p>@Austin: If you’re going to update the future direction of this
proposal you may want to use something from the <em>future
direction</em> part I just posted.</p>
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<div id="bloop_sign_1464161460561202944" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
-- <br>
Adrian Zubarev<br>
Sent with Airmail</div>
</div>
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