Some generic, functional swift methods.

generic.swift

func any<S>(source: [S], predicate: (S) -> Bool) -> Bool {
  for element in source {
    if predicate(element) { return true }
  }
  
  return false
}

func any<S>(source: [S], predicate: (Int, S) -> Bool) -> Bool {
  for (index, element) in enumerate(source) {
    if predicate(index, element) { return true }
  }
  
  return false
}

func every<S>(source: [S], predicate: (S) -> Bool) -> Bool {
  for element in source {
    if !predicate(element) { return false }
  }
  
  return true
}

func every<S>(source: [S], predicate: (Int, S) -> Bool) -> Bool {
  for (index, element) in enumerate(source) {
    if !predicate(index, element) { return false }
  }
  
  return true
}

func none<S>(source: [S], predicate: (S) -> Bool) -> Bool {
  return !any(source, predicate)
}

func none<S>(source: [S], predicate: (Int, S) -> Bool) -> Bool {
  return !any(source, predicate)
}

func head<S>(source: [S]) -> S? {
  return source.first
}

func tail<S>(source: [S]) -> [S] {
  if source.count <= 1 { return [] }
  return Array(source[1..<source.count])
}

extension Array {
  func any(predicate: (T) -> Bool) -> Bool {
    for element in self {
      if predicate(element) { return true }
    }
    
    return false
  }
  
  func any(predicate: (Int, T) -> Bool) -> Bool {
    for (index, element) in enumerate(self) {
      if predicate(index, element) { return true }
    }
    
    return false
  }
  
  func every(predicate: (T) -> Bool) -> Bool {
    for element in self {
      if !predicate(element) { return false }
    }
    
    return true
  }
  
  func every(predicate: (Int, T) -> Bool) -> Bool {
    for (index, element) in enumerate(self) {
      if !predicate(index, element) { return false }
    }
    
    return true
  }
  
  func none(predicate: (T) -> Bool) -> Bool {
    return !any(predicate)
  }
  
  func none(predicate: (Int, T) -> Bool) -> Bool {
    return !any(predicate)
  }
  
  var head: T? {
    return self.first
  }
  
  var tail: Array<T> {
    if count <= 1 { return [] }
    return Array(self[1..<count])
  }
}