everyOf.swift

extension SequenceType where Generator.Element: SequenceType {
  var everyOf: [[Generator.Element.Generator.Element]] {
    var seqGen = self.generate()
    return seqGen.next().map {
      let fSeq = Array($0)
      return AnySequence{seqGen}.everyOf.flatMap {
        lSeq in fSeq.map{ [$0] + lSeq }
      }
    } ?? [[]]
  }
}


extension SequenceType where Generator.Element: CollectionType {
  var everyOf: [[Generator.Element.Generator.Element]] {
    var seqGen = self.generate()
    return seqGen.next().map {
      fSeq in AnySequence{seqGen}.everyOf.flatMap {
        lSeq in fSeq.map{ [$0] + lSeq }
      }
    } ?? [[]]
  }
}