Пузырьковая шейкер сортировка

let shakerSort () =
    let a = [|9;8;7;6;5;4;3;2;1;0|]
    let mutable l = 1
    let mutable r = a.Length - 1
    let mutable k = r
    let mutable x = a.[0]
    let mutable cond = true
    while cond do
        for j = r downto l do
            if a.[j-1] > a.[j] 
            then x <- a.[j-1]; a.[j-1] <- a.[j]; a.[j] <- x; k <- j
            else ()
        l <- k + 1
        for j = l to r do
            if a.[j-1] > a.[j]
            then x <- a.[j-1]; a.[j-1] <- a.[j]; a.[j] <- x; k <- j
             else ()
        r <- k - 1 
        cond <- (l < r) 
    printfn "%A" a
 

do shakerSort ()