Some Sort Algorithms in F#

// insertSort

let rec insert x lst =
   match lst with
   | [] -> [x]
   | y::rest -> if x < y then x::y::rest else y::(insert x rest)

let rec insertSort = function
   | [] -> []
   | x::rest -> insert x (insertSort rest)
  
  
// mergeSort
let rec split = function
   | [] -> ([], [])
   | a::[] -> ([a], [])
   | a::b::rest -> let p, q = split rest in (a::p, b::q)

let rec merge p q =
   match p, q with
   | [], [] -> []
   | a, [] -> a
   | [], a -> a
   | x::xs, y::ys when x<=y -> x::merge xs q
   | x::xs, y::ys -> y::merge p ys
  
let rec mergeSort = function
   | [] -> []
   | a::[] -> [a]
   | lst ->
       let p, q = split lst
       let ps = mergeSort p
       let qs = mergeSort q
       merge ps qs
      
// quickSort
let rec quickSort = function
   | [] -> []
   | [a] -> [a]
   | x::xs ->
       quickSort [for y in xs do if y<=x then yield y]
       @ [x]
       @ quickSort [for y in xs do if y>x then yield y]