Add tasks for all the new languages

Task/Flatten-a-list/Swift/flatten-a-list-1.swift

@@ -0,0 +1,31 @@
+func list(s: Any...) -> [Any] {
+  return s
+}
+
+func flatten<T>(s: [Any]) -> [T] {
+  var r = [T]()
+  for e in s {
+    switch e {
+    case let a as [Any]:
+      r += flatten(a)
+    case let x as T:
+      r.append(x)
+    default:
+      assert(false, "value of wrong type")
+    }
+  }
+  return r
+}
+
+let s = list(list(1),
+  2,
+  list(list(3, 4), 5),
+  list(list(list())),
+  list(list(list(6))),
+  7,
+  8,
+  list()
+)
+println(s)
+let result : [Int] = flatten(s)
+println(result)

Task/Flatten-a-list/Swift/flatten-a-list-2.swift

@@ -0,0 +1,29 @@
+func list(s: Any...) -> [Any] {
+  return s
+}
+
+func flatten<T>(s: [Any]) -> [T] {
+  return s.flatMap {
+    switch $0 {
+    case let a as [Any]:
+      return flatten(a)
+    case let x as T:
+      return [x]
+    default:
+      assert(false, "value of wrong type")
+    }
+  }
+}
+
+let s = list(list(1),
+  2,
+  list(list(3, 4), 5),
+  list(list(list())),
+  list(list(list(6))),
+  7,
+  8,
+  list()
+)
+println(s)
+let result : [Int] = flatten(s)
+println(result)

Task/Flatten-a-list/Swift/flatten-a-list-3.swift

@@ -0,0 +1,47 @@
+func list(s: Any...) -> [Any]
+{
+    return s
+}
+
+func flatten<T>(array: [Any]) -> [T]
+{
+    var result: [T] = []
+    var workstack: [(array: [Any], lastIndex: Int)] = [(array, 0)]
+
+    workstackLoop: while !workstack.isEmpty
+    {
+        for element in workstack.last!.array.suffixFrom(workstack.last!.lastIndex)
+        {
+            workstack[workstack.endIndex - 1].lastIndex++
+
+            if let element = element as? [Any]
+            {
+                workstack.append((element, 0))
+
+                continue workstackLoop
+            }
+
+            result.append(element as! T)
+        }
+
+        workstack.removeLast()
+    }
+
+    return result
+}
+
+let input = list(list(1),
+    2,
+    list(list(3, 4), 5),
+    list(list(list())),
+    list(list(list(6))),
+    7,
+    8,
+    list()
+)
+
+print(input)
+
+let result: [Int] = flatten(input)
+
+print(result)