let rec map (f,ls) = match ls with
 | Nil -> Nil
 | Cons(x,xs) -> Cons(f x,map (f,xs));;
type 'a mylist = Nil | Cons of 'a * 'a mylist;;
let rec map (f,ls) = match ls with
 | Nil -> Nil
 | Cons(x,xs) -> Cons(f x,map (f,xs));;
let rec map f ls = match ls with
 | Nil -> Nil
 | Cons(x,xs) -> Cons(f x,map f xs);;
map succ Nil;;
succ;;
succ 1;;
map succ Nil;;
map succ Cons(2,Cons(1,Nil));;
map succ (Cons(2,Cons(1,Nil)));;
let map_succ = map succ;
map_succ (Cons(2,Cons(1,Nil)));;
[];;
1::[];;
1::2::[];;
1::2::3::[];;
(1::(2::(3::[])));;
(((1::2)::3)::[]);;
let hd = function
 | [] -> failwith "hd"
 | x::xs -> x;;
hd [];;
hd [1;2;3;4;5];;
let rec (@) xs ys = match xs with
 | [] -> ys
 | x::xs -> x::(xs@ys);;
[1;2]@[3;4];;
let rec (@) xs ys = match ys with
 | [] -> xs
 | y::ys -> (xs@[y])@ys;;
[1;2]@[3;4];;
(<);;
let rec replicate n x = if n < 1 then [] else x::replicate (n-1) x;;
replicate 2 'c';;
replicate 2 [1;2];;
replicate 2 [[1;2];[3]];;
let rec range m n = if m >= n then [] else m::range (m+1) n;;
range 1 3;;
range 3 2;;
range 3 3;;
range 1 100;;
range 1 1000;;
range 1 10000;;
range 1 100000;;
range 1 1000000;;
let rec sum = function
 | [] -> 0
 | x::xs -> x + sum xs;;
sum [1;2;3];;
sum (range 1 100);;
let rec prod = function
 | [] -> 1
 | x::xs -> x * prod xs;;
prod (range 1 100);;
prod (range 1 2);;
prod  [1;2;3];;
prod (range 1 10);;
prod (range 30);;
prod (range 1 30);;
let rec foldr f b = function [] -> b
| x::xs -> f x (foldr f b xs);;
let sum xs = foldr (+) 0 xs;;
sum [1;2;3];;
let sum = foldr (+) 0;;
foldr (^) "" ["1";"2";"3"];;
(^);;
let space x y = x ^ " " ^ y;;
foldr (space) "" ["1";"2";"3"];;
let rec filter p xs = match xs with
 | [] -> []
 | x::xs -> if p x then x::filter p xs else filter p xs;;
filter (fun x -> x < 3) [1;2;3;4];;
filter (fun x -> x < 3) [1;2;3;4;1;2;3];;
let even x = x mod 2 = 0;;
filter even [1;2;3;4;1;2;3];;
let take n xs = if n < 0 then [] else match xs with
 | [] -> []
 | x::xs -> x::take (n-1) xs;;
let rec take n xs = if n < 0 then [] else match xs with
 | [] -> []
 | x::xs -> x::take (n-1) xs;;
take 0 [1;2;3];;
take 2 [1;2;3];;
take 1 [1;2;3];;
take 100 [1;2;3];;