<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto"><div>Would it let me get a property if it does not correspond to a property, or computed property? </div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">For example, would I be able to get the value returned by a fullName() instance method that concatenates the firstName and lastName properties together and returns the result? Or would it only work if fullName were implemented as a computed property as opposed to an instance method? </div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature">Thanks</div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature"><br></div><div id="AppleMailSignature"><br></div><div>On May 27, 2016, at 2:59 PM, Austin Zheng <<a href="mailto:austinzheng@gmail.com">austinzheng@gmail.com</a>> wrote:<br><br></div><blockquote type="cite"><div><div dir="ltr">Yes, it was pretty much meant as a KVC-like feature for Swift. Get a reference to a property from a string which would allow you to get and set its value.<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, May 27, 2016 at 11:53 AM, Ricardo Parada <span dir="ltr"><<a href="mailto:rparada@mac.com" target="_blank">rparada@mac.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word"><span class=""><br><div><blockquote type="cite"><div>On May 26, 2016, at 9:25 PM, Austin Zheng via swift-evolution <<a href="mailto:swift-evolution@swift.org" target="_blank">swift-evolution@swift.org</a>> wrote:</div><br><div><div style="font-family:Helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">```</div><div style="font-family:Helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">myPerson.typedReadWriteProperty<Int>("age")?.set(30)</div><div style="font-family:Helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px"><br></div><div style="font-family:Helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">try myPerson.allNamedProperties["age"]?.set(30)</div><div style="font-family:Helvetica;font-size:14px;font-style:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">```</div><br></div></blockquote></div><br></span><div>Can you elaborate on what this API would be used for? KVC? For instance, I played with Mirror the other day and my code to get a value given the property name looked more like this:</div><div><br></div><div>let age = myPerson.value(forKey:”age”) as! Int</div><div><br></div><div>And this is what I did:</div><div><br></div><div>// KVC stands for key-value-coding… but I only know how to get values. I don’t know how to set values</div><div><br></div><div><div>protocol KVC {</div><div> func value(forKey key: String) -> Any!</div><div>}</div><div><br></div><div>// Default implementation</div><div>extension KVC {</div><div> func value(forKey key: String) -> Any! {</div><div> let aMirror = Mirror(reflecting:self)</div><div> for case let (label?, value) in aMirror.children {</div><div> if label == key {</div><div> return value</div><div> }</div><div> }</div><div> return nil</div><div> }</div><div>}</div><div><br></div><div>public struct Person : KVC {</div><div> let firstName: String</div><div> let lastName: String</div><div> let age: Int</div><div><br></div><div> func fullName() -> String {</div><div> return "\(firstName) \(lastName)"</div><div> }</div><div>}</div><div><br></div><div>let aPerson = Person(firstName:"John", lastName:"Doe", age:48)</div><div><br></div><div>// It works for stored properties</div><div>let lastName = aPerson.value(forKey:"lastName") as! String</div><div>print("Last name is \(lastName)")</div><div><br></div><div>// It does not work for instance methods, i.e. fullName is not a stored property</div><div>let fullName = aPerson.value(forKey:"fullName")</div><div>if fullName != nil {</div><div> print("Full name is \(fullName)")</div><div>} else {</div><div> print("Unable to get fullName via KVC")</div><div>}</div></div><div><br></div><div><br></div><div><br></div></div></blockquote></div><br></div>
</div></blockquote></body></html>