very bad

type 't tree =
| Nil
| Node of 't * 't tree * 't tree

let Leaf x = Node(x, Nil, Nil)

let t = Node(0, Leaf(1), Node(2, Leaf(3), Nil))

let ex = Node('+',Leaf('1'),Node('*',Leaf('1'),Leaf('2')))

type trav_order = Prefix|Infix|Postfix

let rec traverse2 f = function
| Nil -> ()
| Node(x,l,r) -> f x

traverse2 f l
traverse2 f r


let rec traverse tro f = function
| Nil -> ()
| Node(x,l,r) ->
match tro with
| Prefix -> f x; traverse tro f l; traverse tro f r
| Infix -> traverse tro f l; f x; traverse tro f r
| Postfix -> traverse tro f l; traverse tro f r; f x

let rec fold f acc = function
| Nil -> acc
| Node(x,l,r)->
    let x1 = fold f acc 1
    let x2 = f x x1
    fold f x2 r

fold (fun a b -> string(a) + b) "" ex

let rec insert x = function
| Nil -> Leaf x
| Node(z,l,r) as N ->
    if x<z then Node(z, insert x l, r)
    elif x>z then Node(z, l, insert x r)
    else N

let Rnd = new System.Random()

let L = [for x in [1..10] -> Rnd.Next(1,100)]

let flip f x y = f y x
let curry f x y = f(x,y)
L |> List.fold (flip insert) Nil |> fold (curry List.Cons) []



let rec insert x = function
| Nil -> Leaf (x,1)
| Node((z,n),l,r) ->
    if x<z then Node((z,n), insert x l, r)
    elif x>z then Node((z,n), l, insert x r)
    else Node((x,n+1),l,r)

open System.IO
File.ReadAllLines(@"C:/Users/pavel/YandexDisk/programming/fsharp/text.txt")
|> Array.
|> Array.collect (fun s -> s.Split([|' ';'-';',';':';'.|]))
|> Array.filter (fun x x -> x.Length>0)
|> Array.fold (flip insert) Nil
|> fold (curry List.Cons) []
// |> List.sordBy (fun (w,f) -> -f)
|> List.sordBy ((~-)<<snd)
|> List.take 5


5 |> (+) 1 |> (*) 2 |> printfn "%d"

let plus1 x f = f(x+1)
let times2 x f = f(x*2)

plus1 5 <| fun

let rec len f = function
| [] -> f(0)
| _::t -> len()


let rec size f = function
| Nil -> f 0
| Node(_l,r) ->
    l |> size (fun x1 ->
        r |> size (fun x2 -> f(1+x1+x2)))

size id T