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<title>CodeMirror: ML-like mode</title>
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    <li><a href="../index.html">Language modes</a>
    <li><a class=active href="#">ML-like</a>
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<article>
<h2>OCaml mode</h2>

<textarea id="ocamlCode">
(* Summing a list of integers *)
let rec sum xs =
  match xs with
    | []       -&gt; 0
    | x :: xs' -&gt; x + sum xs'

(* Quicksort *)
let rec qsort = function
   | [] -&gt; []
   | pivot :: rest -&gt;
       let is_less x = x &lt; 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 -&gt; a
  | _ -&gt; 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' &lt; 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 -&gt; "S" ^ k) "0"
let _ = to_string (add (succ two) two)

(* Elementary functions *)
let square x = x * x;;
let rec fact x =
  if x &lt;= 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
  | [] -&gt; []
  | x :: l -&gt; insert x (sort l)

and insert elem = function
  | [] -&gt; [elem]
  | x :: l -&gt;
      if elem &lt; 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) &lt;- p1.(i) done;
  for i = 0 to n2 - 1 do result.(i) &lt;- 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 *)
</textarea>

<h2>F# mode</h2>
<textarea id="fsharpCode">
module CodeMirror.FSharp

let rec fib = function
    | 0 -> 0
    | 1 -> 1
    | n -> fib (n - 1) + fib (n - 2)

type Point =
    {
        x : int
        y : int
    }

type Color =
    | Red
    | Green
    | Blue

[0 .. 10]
|> List.map ((+) 2)
|> List.fold (fun x y -> x + y) 0
|> printf "%i"
</textarea>

var fsharpEditor = CodeMirror.fromTextArea(document.getElementById('fsharpCode'), {
    mode: 'text/x-fsharp',
    lineNumbers: true,
    matchBrackets: true
  });
</script>

<p><strong>MIME types defined:</strong> <code>text/x-ocaml</code> (OCaml) and <code>text/x-fsharp</code> (F#).</p>
</article>