Learn OCAML with Real Code Examples

let count = ref 0
let isDark = ref false

let updateUI () =
  Printf.printf "Counter: %d\n" !count;
  Printf.printf "Theme: %s\n" (if !isDark then "Dark" else "Light")

let increment () = count := !count + 1; updateUI ()
let decrement () = count := !count - 1; updateUI ()
let reset () = count := 0; updateUI ()
let toggleTheme () = isDark := not !isDark; updateUI ()

(* Simulate actions *)
updateUI (); increment (); increment (); toggleTheme (); decrement (); reset ();

Demonstrates a simple counter with theme toggling using OCaml references and functions.

let add a b = a + b
let () = Printf.printf "%d\n" (add 10 20)

Adds two numbers and prints the result.

let rec factorial n = if n <= 1 then 1 else n * factorial (n - 1)
let () = Printf.printf "%d\n" (factorial 5)

Calculates factorial recursively.

let rec fib n = if n < 2 then n else fib (n - 1) + fib (n - 2)
let () = for i = 0 to 9 do Printf.printf "%d\n" (fib i) done

Generates first 10 Fibonacci numbers recursively.

let max a b = if a > b then a else b
let () = Printf.printf "%d\n" (max 10 20)

Finds the maximum of two numbers.

let rec sum_list lst = match lst with [] -> 0 | x::xs -> x + sum_list xs
let () = Printf.printf "%d\n" (sum_list [1;2;3;4;5])

Sums elements of a list recursively.

let print_even lst = List.iter (fun x -> if x mod 2 = 0 then Printf.printf "%d\n" x) lst
let () = print_even [1;2;3;4;5]

Prints even numbers from a list.

let count = ref 3
if !count < 5 then count := !count + 1
let () = Printf.printf "%d\n" !count

Increment counter only if less than 5.

let count = ref 0
count := !count + 1
count := !count + 1
let () = Printf.printf "%d\n" !count
count := 0
let () = Printf.printf "%d\n" !count

Counter that increments and can be reset.

let isDark = ref false
let () = Printf.printf "%s\n" (if !isDark then "Dark" else "Light")
isDark := not !isDark
let () = Printf.printf "%s\n" (if !isDark then "Dark" else "Light")
isDark := not !isDark
let () = Printf.printf "%s\n" (if !isDark then "Dark" else "Light")

Toggles theme multiple times.