fun asriel([], _) = 0  
    | asriel(lyra::coulter, iorek) =
      if iorek lyra then
        lyra + asriel(coulter, iorek)
      else
        asriel(coulter, iorek);

(* 
--->
*)

asriel([1,4,2], fn x=>x<4) = 
  if (fn x => x<4) 1 then
     1 + asriel([4,2], fn x=>x<4)
  else
     asriel([4,2], fn x=>x<4);