blocks|key|109372|text|看起来这是一些反射支持的开始：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|109373|class+Fruit+{
++++var+name="Apple"
}

reflect(Fruit()).count+++++++++//+1
reflect(Fruit())[0].0++++++++++//+"name"
reflect(Fruit())[0].1.summary++//+"Apple"|code-block|syntax|javascript|109374|出自mchambers+gist，这里：https://gist.github.com/mchambers/fb9da554898dae3e54f2|offset|length|109375|entityMap|0|LINK|mutability|MUTABLE|url|https://gist.github.com/mchambers/fb9da554898dae3e54f2^0|0|0|K|1I|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

Looks like there's the start of some reflection support:

<pre><code>class Fruit {
 var name="Apple"
}

reflect(Fruit()).count // 1
reflect(Fruit())[0].0 // "name"
reflect(Fruit())[0].1.summary // "Apple"
</code></pre>

From mchambers gist, here:
<a href="https://gist.github.com/mchambers/fb9da554898dae3e54f2">https://gist.github.com/mchambers/fb9da554898dae3e54f2</a>

blocks|key|109418|text|目前看来，Swift反射API对Apple来说不是一个高优先级的东西。但是，除了@stevex+answer之外，标准库中还有另一个函数可以提供帮助。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|109419|从beta+6开始，_stdlib_getTypeName获取变量的损坏类型名称。将此内容粘贴到空操场中：|style|CODE|109420|import+Foundation

class+PureSwiftClass+{
}

var+myvar0+=+NSString()+//+Objective-C+class
var+myvar1+=+PureSwiftClass()
var+myvar2+=+42
var+myvar3+=+"Hans"

println(+"TypeName0+=+\(_stdlib_getTypeName(myvar0))")
println(+"TypeName1+=+\(_stdlib_getTypeName(myvar1))")
println(+"TypeName2+=+\(_stdlib_getTypeName(myvar2))")
println(+"TypeName3+=+\(_stdlib_getTypeName(myvar3))")|code-block|syntax|javascript|109421|输出为：|109422|TypeName0+=+NSString
TypeName1+=+_TtC13__lldb_expr_014PureSwiftClass
TypeName2+=+_TtSi
TypeName3+=+_TtSS|109423|Ewan+Swick's+blog+entry帮助破译这些字符串：|109424|例如，_TtSi代表Swift的内部Int类型。|109425|Mike+Ash+has+a+great+blog+entry+covering+the+same+topic。|109426|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/24069875/292145|1|http://www.eswick.com/2014/06/inside-swift/|2|https://www.mikeash.com/pyblog/friday-qa-2014-08-15-swift-name-mangling.html^0|1C|6|0|0|A|J|0|0|0|0|0|N|1|0|3|5|I|3|0|0|1J|2|0^^$0|@$1|2|3|4|5|6|7|18|8|@]|9|@$A|19|B|1A|1|1B]]|C|$]]|$1|D|3|E|5|6|7|1C|8|@$A|1D|B|1E|F|G]]|9|@]|C|$]]|$1|H|3|I|5|J|7|1F|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1G|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1H|8|@]|9|@]|C|$K|L]]|$1|Q|3|R|5|6|7|1I|8|@]|9|@$A|1J|B|1K|1|1L]]|C|$]]|$1|S|3|T|5|6|7|1M|8|@$A|1N|B|1O|F|G]|$A|1P|B|1Q|F|G]]|9|@]|C|$]]|$1|U|3|V|5|6|7|1R|8|@]|9|@$A|1S|B|1T|1|1U]]|C|$]]|$1|W|3|-4|5|6|7|1V|8|@]|9|@]|C|$]]]|X|$Y|$5|Z|10|11|C|$12|13]]|14|$5|Z|10|11|C|$12|15]]|16|$5|Z|10|11|C|$12|17]]]]

It seems that a Swift reflection API is not a high priority for Apple at the moment. But besides @stevex <a href="https://stackoverflow.com/a/24069875/292145">answer</a> there is another function in the standard library that helps.

As of beta 6 <code>_stdlib_getTypeName</code> gets the mangled type name of a variable. Paste this into an empty playground:

<pre><code>import Foundation

class PureSwiftClass {
}

var myvar0 = NSString() // Objective-C class
var myvar1 = PureSwiftClass()
var myvar2 = 42
var myvar3 = "Hans"

println( "TypeName0 = \(_stdlib_getTypeName(myvar0))")
println( "TypeName1 = \(_stdlib_getTypeName(myvar1))")
println( "TypeName2 = \(_stdlib_getTypeName(myvar2))")
println( "TypeName3 = \(_stdlib_getTypeName(myvar3))")
</code></pre>

The output is:

<pre><code>TypeName0 = NSString
TypeName1 = _TtC13__lldb_expr_014PureSwiftClass
TypeName2 = _TtSi
TypeName3 = _TtSS
</code></pre>

<a href="http://www.eswick.com/2014/06/inside-swift/" rel="nofollow noreferrer">Ewan Swick's blog entry</a> helps to decipher these strings: 

e.g. <code>_TtSi</code> stands for Swift's internal <code>Int</code> type.

<a href="https://www.mikeash.com/pyblog/friday-qa-2014-08-15-swift-name-mangling.html" rel="nofollow noreferrer">Mike Ash has a great blog entry covering the same topic</a>.

blocks|key|4615634|text|Swift+5中没有reflect关键字，现在您可以使用|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|4615635|struct+Person+{
++++var+name="name"
++++var+age+=+15
}

var+me+=+Person()
var+mirror+=+Mirror(reflecting:+me)

for+case+let+(label?,+value)+in+mirror.children+{
++++print+(label,+value)
}|code-block|syntax|javascript|4615636|entityMap^0|A|7|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@$9|N|A|O|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|P|8|@]|D|@]|E|$I|J]]|$1|K|3|-4|5|6|7|Q|8|@]|D|@]|E|$]]]|L|$]]

No <code>reflect</code> keyword in Swift 5, now you can use 

<pre><code>struct Person {
 var name="name"
 var age = 15
}

var me = Person()
var mirror = Mirror(reflecting: me)

for case let (label?, value) in mirror.children {
 print (label, value)
}

</code></pre>

Does Swift support reflection? e.g. is there something like <code>valueForKeyPath:</code> and <code>setValue:forKeyPath:</code> for Swift objects? 

Actually does it even have a dynamic type system, something like <code>obj.class</code> in Objective-C?

Does Swift support reflection?

Objective-C

Swift

Swift支持反射吗？例如，Swift对象有没有像valueForKeyPath:和setValue:forKeyPath:这样的东西？实际上它有没有像Objective-C中的obj.class这样的动态类型系统呢？

问Swift支持反射吗？
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