dropWhile using foldr

dropwhile.fs

let dropWhile : ('a -> bool) -> list<'a> -> list<'a> = fun pred xs -> 
    let (_, ys) = List.foldBack (fun x (xs, ys) -> let xs' = x :: xs in if pred x then xs', ys else xs', xs') xs ([], [])
    ys
    
// example 1 
[1..10] |> dropWhile (fun x -> x <= 5) // [6..10] 

// example 2
[1..10] |> dropWhile (fun x -> false) // [1..10] 

// example 3
[1..10] |> dropWhile (fun x -> true) // [] 

// example 4
[1; 6; 1; 7] |> dropWhile (fun x -> x <= 5) // [6; 1; 7]