(* Merging and sorting *) fun merge order =  let fun loop [] ys = ys        | loop xs [] = xs        | loop (xs as x::xr) (ys as y::yr) =            if order x y then               x :: loop xr ys             else               y :: loop xs yr  in loop end; fun sort order l =  let fun initList [] = []        | initList [e] = [[e]]        | initList (x1::x2::xs) =            (if order x1 x2 then [x1, x2] else [x2, x1]) :: initList xs      fun merge2 (xs1::xs2::xss) = merge order xs1 xs2 :: merge2 xss        | merge2 x = x      fun mergeAll [] = []        | mergeAll [xs] = xs        | mergeAll xss = mergeAll (merge2 xss)  in mergeAll(initList l) end;