SwiftSet.swift

//
// Set
//

struct MySet<KeyType : Hashable> : Sequence
{
  var dictionaryOfItems = Dictionary<KeyType,Bool>()
  
  init() {}
  init(array:Array<KeyType>) {
    for item in array {
      self.dictionaryOfItems.updateValue(true, forKey: item)
    }
  }
  
  mutating
  func addObject(item:KeyType) -> Void {
    self.dictionaryOfItems.updateValue(true, forKey: item)
  }
  
  func containsObject(item:KeyType) -> Bool {
    return self.dictionaryOfItems[item].getLogicValue()
  }
  
  func generate() -> SetGeneratorType<KeyType> {
    let dictGenerator = self.dictionaryOfItems.generate()
    return SetGeneratorType<KeyType>(dictGenerator)
  }
}

struct SetGeneratorType<KeyType:Hashable> : Generator
{
  var backingDictionaryGenerator:DictionaryGenerator<KeyType,Bool>
  init(_ dictGenerator:DictionaryGenerator<KeyType,Bool>)
  {
    self.backingDictionaryGenerator = dictGenerator
  }
  
  mutating
  func next() -> (KeyType)?
  {
    let nextDictElement = backingDictionaryGenerator.next()
    switch (nextDictElement) {
    case let Optional<(KeyType,Bool)>.None:
      return Optional<KeyType>.None
    case let Optional<(KeyType,Bool)>.Some(item,_):
      return Optional<KeyType>.Some(item)
    }
  }
}