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Ocaml

Objective CAML, also known as Ocaml or O'Caml for short, is an advanced programming language based on the ML family. Caml stands for Categorically Abstract Machine Language.

To the functional and imperative features of Standard ML, it adds object-oriented concepts and some minor syntax differences.

Ocaml provides both a bytecode compiler and a native code compiler, and the latter has been ported to a large number of platforms. The code generated by the native compiler is typically comparable to C/C++ in speed.

Powerful features of the language include a static type system, pattern matching, an exception mechanism, and automatic memory management. Ocaml distributions include general purpose libraries and are available for a wide range of platforms, including Unix and Windows.

Ocaml is used in a wide range of applications including thoerem proving and program analysis. It is used as an introductory language in many places, including Caltech.

Example code

(* List manipulation *)

 (* The procedures below work on lists of any type *)

 (* Length of a list *)
 let rec length  = function
   |[] -> 0
   |x::xs -> 1 + length xs;;

 (* Insertion sort *)
 (* An order relation must exist *)
 let rec sort = function
   |[] -> []
   |x::xs -> insert x (sort xs)
 and insert e = function
   |[] -> [e]
   |x::xs -> if x > e 
             then e::x::xs 
             else x::(insert e xs);;

 # let l =
 ["The"; "quick"; "brown"; "fox"; "jumps"; "over"; "the"; "lazy"; "dog"];

 # length l;;
 - : int = 7

 # sort l;;
 - : string list = 
 ["The"; "brown"; "dog"; "fox"; "jumps"; "lazy"; "over"; "quick"; "the"]
(* Trees *)

 (* Definition of a binary tree, of any type 'a *)
 type 'a tree = Node | Tree of ('a tree * 'a * 'a tree) ;;

 let a = Tree(Node, 4, Tree(Node, 2, Node)) ;;
 
 (* Height of a tree *)
 let rec height = function
   |Node -> 0
   |Tree(left, _, right) -> 1 + max (height left) (height right)  ;;

 # height a;;
 - : int = 2
(* Search of a root using the dichotomy method *)

 let rec dicho f min max eps =
   let fmin = f min and fmax = f max in
     if fmin *. fmax > 0.
     then failwith "No root"
     else if max -. min < eps then (min, max) (* return an interval *)
     else let mid = (min +. max) /. 2. in
       if (f mid) *. fmin < 0.
       then dicho f min mid eps
       else dicho f mid max eps ;;

 (* Approximation of the square root of 2 *)
 # dicho (fun x -> x *. x -. 2.) 0. 10. 0.000000001;;
 - : float * float = (1.4142135618, 1.41421356238)
See also: F sharp programming language

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