added ExpressibleByArrayLiteral to the Linked List and wrote test for the new initializer.

Author: imdanielsp

Linked List/LinkedList.playground/Contents.swift

@@ -10,7 +10,7 @@ public class LinkedListNode<T> {
   }
 }
 
-public class LinkedList<T> {
+public final class LinkedList<T> {
   public typealias Node = LinkedListNode<T>
 
   fileprivate var head: Node?
@@ -187,14 +187,22 @@ extension LinkedList {
   }
 }
 
-extension LinkedList {
+extension LinkedList: ExpressibleByArrayLiteral {
   convenience init(array: Array<T>) {
     self.init()
 
     for element in array {
       self.append(element)
     }
   }
+    
+  public convenience init(arrayLiteral elements: T...) {
+      self.init()
+    
+      for element in elements {
+          self.append(element)
+      }
+  }
 }
 
 let list = LinkedList<String>()
@@ -255,3 +263,13 @@ list[0]                        // "Swift"
 
 list.remove(atIndex: 0)        // "Swift"
 list.count                     // 0
+
+let linkedList: LinkedList<Int> = [1, 2, 3, 4] // [1, 2, 3, 4]
+linkedList.count               // 4
+linkedList[0]                  // 1
+
+// Infer the type from the array
+let listArrayLiteral2: LinkedList = ["Swift", "Algorithm", "Club"]
+listArrayLiteral2.count        // 3
+listArrayLiteral2[0]           // "Swift"
+listArrayLiteral2.removeLast() // "Club"

Linked List/LinkedList.swift

@@ -8,7 +8,7 @@ public class LinkedListNode<T> {
     }
 }
 
-public class LinkedList<T> {
+public final class LinkedList<T>: ExpressibleByArrayLiteral {
     public typealias Node = LinkedListNode<T>
 
     fileprivate var head: Node?
@@ -203,4 +203,12 @@ extension LinkedList {
             self.append(element)
         }
     }
+  
+    public convenience init(arrayLiteral elements: T...) {
+      self.init()
+    
+      for element in elements {
+        self.append(element)
+      }
+    }
 }

Linked List/Tests/LinkedListTests.swift

@@ -248,4 +248,26 @@ class LinkedListTest: XCTestCase {
     XCTAssertTrue(last === list.first)
     XCTAssertEqual(nodeCount, list.count)
   }
+  
+  func testArrayLiteralInitTypeInfer() {
+    let arrayLiteralInitInfer: LinkedList = [1.0, 2.0, 3.0]
+    
+    XCTAssertEqual(arrayLiteralInitInfer.count, 3)
+    XCTAssertEqual(arrayLiteralInitInfer.first?.value, 1.0)
+    XCTAssertEqual(arrayLiteralInitInfer.last?.value, 3.0)
+    XCTAssertEqual(arrayLiteralInitInfer[1], 2.0)
+    XCTAssertEqual(arrayLiteralInitInfer.removeLast(), 3.0)
+    XCTAssertEqual(arrayLiteralInitInfer.count, 2)
+  }
+  
+  func testArrayLiteralInitExplicit() {
+    let arrayLiteralInitExplicit: LinkedList<Int> = [1, 2, 3]
+    
+    XCTAssertEqual(arrayLiteralInitExplicit.count, 3)
+    XCTAssertEqual(arrayLiteralInitExplicit.first?.value, 1)
+    XCTAssertEqual(arrayLiteralInitExplicit.last?.value, 3)
+    XCTAssertEqual(arrayLiteralInitExplicit[1], 2)
+    XCTAssertEqual(arrayLiteralInitExplicit.removeLast(), 3)
+    XCTAssertEqual(arrayLiteralInitExplicit.count, 2)
+  }
 }