Use lower camel case in enum case

Author: Nagasawa Hiroki

Binary Tree/BinaryTree.playground/Contents.swift

@@ -1,14 +1,14 @@
 //: Playground - noun: a place where people can play
 
 public indirect enum BinaryTree<T> {
-  case Node(BinaryTree<T>, T, BinaryTree<T>)
-  case Empty
+  case node(BinaryTree<T>, T, BinaryTree<T>)
+  case empty
 
   public var count: Int {
     switch self {
-    case let .Node(left, _, right):
+    case let .node(left, _, right):
       return left.count + 1 + right.count
-    case .Empty:
+    case .empty:
       return 0
     }
   }
@@ -17,9 +17,9 @@ public indirect enum BinaryTree<T> {
 extension BinaryTree: CustomStringConvertible {
   public var description: String {
     switch self {
-    case let .Node(left, value, right):
+    case let .node(left, value, right):
       return "value: \(value), left = [" + left.description + "], right = [" + right.description + "]"
-    case .Empty:
+    case .empty:
       return ""
     }
   }
@@ -28,24 +28,24 @@ extension BinaryTree: CustomStringConvertible {
 
 
 // leaf nodes
-let node5 = BinaryTree.Node(.Empty, "5", .Empty)
-let nodeA = BinaryTree.Node(.Empty, "a", .Empty)
-let node10 = BinaryTree.Node(.Empty, "10", .Empty)
-let node4 = BinaryTree.Node(.Empty, "4", .Empty)
-let node3 = BinaryTree.Node(.Empty, "3", .Empty)
-let nodeB = BinaryTree.Node(.Empty, "b", .Empty)
+let node5 = BinaryTree.node(.empty, "5", .empty)
+let nodeA = BinaryTree.node(.empty, "a", .empty)
+let node10 = BinaryTree.node(.empty, "10", .empty)
+let node4 = BinaryTree.node(.empty, "4", .empty)
+let node3 = BinaryTree.node(.empty, "3", .empty)
+let nodeB = BinaryTree.node(.empty, "b", .empty)
 
 // intermediate nodes on the left
-let aMinus10 = BinaryTree.Node(nodeA, "-", node10)
-let timesLeft = BinaryTree.Node(node5, "*", aMinus10)
+let aMinus10 = BinaryTree.node(nodeA, "-", node10)
+let timesLeft = BinaryTree.node(node5, "*", aMinus10)
 
 // intermediate nodes on the right
-let minus4 = BinaryTree.Node(.Empty, "-", node4)
-let divide3andB = BinaryTree.Node(node3, "/", nodeB)
-let timesRight = BinaryTree.Node(minus4, "*", divide3andB)
+let minus4 = BinaryTree.node(.empty, "-", node4)
+let divide3andB = BinaryTree.node(node3, "/", nodeB)
+let timesRight = BinaryTree.node(minus4, "*", divide3andB)
 
 // root node
-let tree = BinaryTree.Node(timesLeft, "+", timesRight)
+let tree = BinaryTree.node(timesLeft, "+", timesRight)
 
 print(tree)
 tree.count  // 12
@@ -54,23 +54,23 @@ tree.count  // 12
 
 extension BinaryTree {
   public func traverseInOrder(process: (T) -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       left.traverseInOrder(process: process)
       process(value)
       right.traverseInOrder(process: process)
     }
   }
 
   public func traversePreOrder(process: (T) -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       process(value)
       left.traversePreOrder(process: process)
       right.traversePreOrder(process: process)
     }
   }
 
   public func traversePostOrder(process: (T) -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       left.traversePostOrder(process: process)
       right.traversePostOrder(process: process)
       process(value)

Binary Tree/BinaryTree.swift

@@ -4,14 +4,14 @@
   Nodes don't have a reference to their parent.
 */
 public indirect enum BinaryTree<T> {
-  case Node(BinaryTree<T>, T, BinaryTree<T>)
-  case Empty
+  case node(BinaryTree<T>, T, BinaryTree<T>)
+  case empty
 
   public var count: Int {
     switch self {
-    case let .Node(left, _, right):
+    case let .node(left, _, right):
       return left.count + 1 + right.count
-    case .Empty:
+    case .empty:
       return 0
     }
   }
@@ -20,33 +20,33 @@ public indirect enum BinaryTree<T> {
 extension BinaryTree: CustomStringConvertible {
   public var description: String {
     switch self {
-    case let .Node(left, value, right):
+    case let .node(left, value, right):
       return "value: \(value), left = [" + left.description + "], right = [" + right.description + "]"
-    case .Empty:
+    case .empty:
       return ""
     }
   }
 }
 
 extension BinaryTree {
   public func traverseInOrder(@noescape process: T -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       left.traverseInOrder(process)
       process(value)
       right.traverseInOrder(process)
     }
   }
 
   public func traversePreOrder(@noescape process: T -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       process(value)
       left.traversePreOrder(process)
       right.traversePreOrder(process)
     }
   }
 
   public func traversePostOrder(@noescape process: T -> Void) {
-    if case let .Node(left, value, right) = self {
+    if case let .node(left, value, right) = self {
       left.traversePostOrder(process)
       right.traversePostOrder(process)
       process(value)
@@ -56,10 +56,10 @@ extension BinaryTree {
 
 extension BinaryTree {
   func invert() -> BinaryTree {
-    if case let .Node(left, value, right) = self {
-      return .Node(right.invert(), value, left.invert())
+    if case let .node(left, value, right) = self {
+      return .node(right.invert(), value, left.invert())
     } else {
-      return .Empty
+      return .empty
     }
   }
 }