==, != for SequenceType and Dictionary with SequenceType values

gistfile1.txt

func ==<S: SequenceType where S.Generator.Element: Equatable>(lhs: S, rhs: S) -> Bool {
  var lgen = lhs.generate()
  var rgen = rhs.generate()
  while true {
    let lelem = lgen.next()
    let relem = rgen.next()
    if let lelem = lelem, relem = relem {
      if lelem != relem {
        // elements aren't equal
        return false
      }
    } else if lelem == nil && relem == nil {
      // We're done, exit the loop
      break
    } else {
      // one of the generators was exhausted early
      return false
    }
  }
  return true
}

func !=<S: SequenceType where S.Generator.Element: Equatable>(lhs: S, rhs: S) -> Bool {
  return !(lhs == rhs)
}

func ==<Key: Equatable, Value: SequenceType where Value.Generator.Element: Equatable>(lhs: [Key: Value], rhs: [Key: Value]) -> Bool {
  guard lhs.count == rhs.count else { return false }
  for  (lkey, lvalue) in lhs {
    if let rvalue = rhs[lkey] {
      if lvalue != rvalue {
        return false
      }
    } else {
      // right side didn't have the key
      return false
    }
  }
  return true
}

func !=<Key: Equatable, Value: SequenceType where Value.Generator.Element: Equatable>(lhs: [Key: Value], rhs: [Key: Value]) -> Bool {
  return !(lhs == rhs)
}

print("\(["":[2, 2]] != ["": [2, 2]])")
print("\([2] != [2, 2])")
print("\(["": 2] != ["": 2])")