Proposed solution for kata at http://www.meetup.com/FunctionalKats/events/224121028/

august-kata.fsx

let matches (pattern : string) (x : string) : bool =
    let rec matchesL pattern x =
        match pattern, x with
        | [], [] | ['?'], [] | ['*'], []-> true
        | '?'::pTail, xHead::xTail -> matchesL pTail xTail || matchesL pTail x
        | '*'::pTail, xHead::xTail -> matchesL pTail xTail || matchesL pTail x || matchesL pattern xTail
        | pHead::pTail, xHead::xTail when pHead = xHead -> matchesL pTail xTail
        | _ -> false

    matchesL (Seq.toList pattern) (Seq.toList x)

let findMatches (pattern : string) (xs : seq<string>) : seq<string> =
    Seq.where (matches pattern) xs

This is the equivalent Scala version.

  def matches(p:String)(s:String):Boolean = {
    def matchesL(pattern: List[Char])(x: List[Char]): Boolean = (pattern, x) match {
      case (Nil, Nil) | (List('?'), Nil) | (List('*'), Nil) => true
      case ('?' :: pTail, xHead :: xTail) => matchesL(pTail)(xTail) || matchesL(pTail)(x)
      case ('*' :: pTail, xHead :: xTail) => matchesL(pTail)(xTail) || matchesL(pTail)(x) || matchesL(pattern)(xTail)
      case (pHead :: pTail, xHead :: xTail) if pHead == xHead => matchesL(pTail)(xTail)
      case _ => false
    }
    matchesL(p.toList)(s.toList)
  }

  def findMatches(pattern:String, candidates:List[String]):List[String] =
    candidates.filter(matches(pattern))