update for 6.1 final, code cleanup (get rid of protocol and optional func)

Author: mattneub

bk2ch23p818xml/ch36p1070xml/MyPeopleParser.swift

@@ -13,8 +13,7 @@ class MyPeopleParser : MyXMLParserDelegate {
                 self.makeChild(MyPersonParser.self, elementName: elementName, parser: parser)
             }
     }
-    
-    func finishedChild(s: String) {
+    override func finishedChild(s: String) {
         self.people.append((self.child as MyPersonParser).person)
     }
 

bk2ch23p818xml/ch36p1070xml/MyPersonParser.swift

@@ -4,18 +4,15 @@ import UIKit
 
 class MyPersonParser : MyXMLParserDelegate {
 
-    var person : Person! = nil
+    var person = Person(firstName: "", lastName: "")
 
     func parser(parser: NSXMLParser, didStartElement elementName: String!,
         namespaceURI: String!, qualifiedName qName: String!,
         attributes attributeDict: [NSObject : AnyObject]!) {
             self.makeChild(MyXMLParserDelegate.self, elementName: elementName, parser: parser)
     }
 
-    func finishedChild(s: String) {
-        if self.person == nil {
-            self.person = Person(firstName: "", lastName: "")
-        }
+    override func finishedChild(s: String) {
         self.person.setValue(s, forKey:self.child.name)
     }
 

bk2ch23p818xml/ch36p1070xml/MyXMLParserDelegate.swift

@@ -2,18 +2,14 @@
 
 import UIKit
 
-// protocol as a way of declaring an abstract method to be inherited and implemented by subclasses
-@objc protocol MyXMLParserDelegateProtocol {
-    optional func finishedChild(s:String)
-}
 
-class MyXMLParserDelegate : NSObject, NSXMLParserDelegate, MyXMLParserDelegateProtocol {
-    var text = ""
+class MyXMLParserDelegate : NSObject {
     var name : String!
+    var text = ""
     weak var parent : MyXMLParserDelegate?
     var child : MyXMLParserDelegate!
 
-    required init(name:String!, parent:MyXMLParserDelegate!) {
+    required init(name:String, parent:MyXMLParserDelegate?) {
         self.name = name
         self.parent = parent
         super.init()
@@ -24,21 +20,24 @@ class MyXMLParserDelegate : NSObject, NSXMLParserDelegate, MyXMLParserDelegatePr
         self.child = del
         parser.delegate = del
     }
+    func finishedChild(s:String) {
+        fatalError("Subclass must implement finishedChild:!")
+    }
 
-    // func finishedChild(s:String) {} // subclass may implement as desired
-    
-    // NSXMLParser delegate messages
-    
+}
+
+extension MyXMLParserDelegate : NSXMLParserDelegate {
     func parser(parser: NSXMLParser, foundCharacters string: String!) {
         self.text = self.text + string
     }
 
     func parser(parser: NSXMLParser, didEndElement elementName: String!, namespaceURI: String!, qualifiedName qName: String!) {
         if self.parent != nil {
-            // rather tricky syntax to allow calling optional method; bug in Swift?
-            (self.parent! as MyXMLParserDelegateProtocol).finishedChild?(self.text)
+            self.parent!.finishedChild(self.text)
             parser.delegate = self.parent
         }
     }
 
 }
+
+

bk2ch23p818xml/ch36p1070xml/Person.swift

@@ -6,7 +6,7 @@ class Person: NSObject, NSCoding {
     @NSCopying var firstName : NSString
     @NSCopying var lastName : NSString
 
-    override var description : String! {
+    override var description : String {
         return self.firstName + " " + self.lastName
     }
 
@@ -23,8 +23,8 @@ class Person: NSObject, NSCoding {
     }
 
     required init(coder: NSCoder) {
-        self.lastName = coder.decodeObjectForKey("last")! as NSString
-        self.firstName = coder.decodeObjectForKey("first")! as NSString
+        self.lastName = coder.decodeObjectForKey("last")! as String
+        self.firstName = coder.decodeObjectForKey("first")! as String
         // do not call super init(coder:) in this case
         super.init()
     }

bk2ch23p818xml/ch36p1070xml/ViewController.swift

@@ -6,14 +6,16 @@ class ViewController: UIViewController {
     // if this works, you'll see a list of people appear in the console
 
     @IBAction func doButton (sender:AnyObject!) {
-        let url = NSBundle.mainBundle().URLForResource("folks", withExtension: "xml")!
-        let parser = NSXMLParser(contentsOfURL: url)
-        let people = MyPeopleParser(name:"", parent:nil)
-        parser.delegate = people
-        parser.parse()
-        
-        // ... done, do something with people.people ...
-        println(people.people)
+        if let url = NSBundle.mainBundle().URLForResource("folks", withExtension: "xml") {
+            if let parser = NSXMLParser(contentsOfURL: url) {
+                let people = MyPeopleParser(name:"", parent:nil)
+                parser.delegate = people
+                parser.parse()
+                
+                // ... done, do something with people.people ...
+                println(people.people)
+            }
+        }
     }