CodeMirror: OCaml mode

(* Summing a list of integers *)

let rec sum xs =

  match xs with

    | []       -> 0

    | x :: xs' -> x + sum xs'

(* Quicksort *)

let rec qsort = function

   | [] -> []

   | pivot :: rest ->

       let is_less x = x < pivot in

       let left, right = List.partition is_less rest in

       qsort left @ [pivot] @ qsort right

(* Fibonacci Sequence *)

let rec fib_aux n a b =

  match n with

  | 0 -> a

  | _ -> fib_aux (n - 1) (a + b) a

let fib n = fib_aux n 0 1

(* Birthday paradox *)

let year_size = 365.

let rec birthday_paradox prob people =

    let prob' = (year_size -. float people) /. year_size *. prob  in

    if prob' < 0.5 then

        Printf.printf "answer = %d\n" (people+1)

    else

        birthday_paradox prob' (people+1) ;;

birthday_paradox 1.0 1

(* Church numerals *)

let zero f x = x

let succ n f x = f (n f x)

let one = succ zero

let two = succ (succ zero)

let add n1 n2 f x = n1 f (n2 f x)

let to_string n = n (fun k -> "S" ^ k) "0"

let _ = to_string (add (succ two) two)

(* Elementary functions *)

let square x = x * x;;

let rec fact x =

  if x <= 1 then 1 else x * fact (x - 1);;

(* Automatic memory management *)

let l = 1 :: 2 :: 3 :: [];;

[1; 2; 3];;

5 :: l;;

(* Polymorphism: sorting lists *)

let rec sort = function

  | [] -> []

  | x :: l -> insert x (sort l)

and insert elem = function

  | [] -> [elem]

  | x :: l -> 

      if elem < x then elem :: x :: l else x :: insert elem l;;

(* Imperative features *)

let add_polynom p1 p2 =

  let n1 = Array.length p1

  and n2 = Array.length p2 in

  let result = Array.create (max n1 n2) 0 in

  for i = 0 to n1 - 1 do result.(i) <- p1.(i) done;

  for i = 0 to n2 - 1 do result.(i) <- result.(i) + p2.(i) done;

  result;;

add_polynom [| 1; 2 |] [| 1; 2; 3 |];;

(* We may redefine fact using a reference cell and a for loop *)

let fact n =

  let result = ref 1 in

  for i = 2 to n do

    result := i * !result

   done;

   !result;;

fact 5;;

(* Triangle (graphics) *)

let () =

  ignore( Glut.init Sys.argv );

  Glut.initDisplayMode ~double_buffer:true ();

  ignore (Glut.createWindow ~title:"OpenGL Demo");

  let angle t = 10. *. t *. t in

  let render () =

    GlClear.clear [ `color ];

    GlMat.load_identity ();

    GlMat.rotate ~angle: (angle (Sys.time ())) ~z:1. ();

    GlDraw.begins `triangles;

    List.iter GlDraw.vertex2 [-1., -1.; 0., 1.; 1., -1.];

    GlDraw.ends ();

    Glut.swapBuffers () in

  GlMat.mode `modelview;

  Glut.displayFunc ~cb:render;

  Glut.idleFunc ~cb:(Some Glut.postRedisplay);

  Glut.mainLoop ()

(* A Hundred Lines of Caml - http://caml.inria.fr/about/taste.en.html *)

(* OCaml page on Wikipedia - http://en.wikipedia.org/wiki/OCaml *)