Popular modules in min-caml implementation

• Core (Pervasives) (Plenty)

• Pervasives: The default module

• List (16) — list operations

• Format (10) / Printf (4) — pretty printing

• Str (5) — regular expression

• Arg (3) — parsing of command line arguments

Popular functions in min-caml implementation

• Format module: eprintf (10)

• Printf module: sprintf (3) / printf

• List module: map (6) / fold_left2 (2) / fold_left (2) / tl / length / iter2 / iter / hd / exists

• Str module: matched_group (2) / search_forward / regexp / global_replace

• Arg module: Int (2), parse

• Set module: Make (1)

Some examples (List.map)

# List.map string_of_int [1; 2; 3]
- : string list = ["1"; "2"; "3"]

# List.map (function n -> Array.make n 3) [3; 4; 5];;
- : int array list = [[|3; 3; 3|]; [|3; 3; 3; 3|]; [|3; 3; 3; 3; 3|]]

Some examples (List.fold_left)

# List.fold_left (fun a x -> a + x) 0 [2; 3; 5; 7; 11]  (* sum *);;
- : int = 28

# List.fold_left (fun a x -> a * x) 1 [2; 3; 5; 7; 11]  (* product *);;
- : int = 2310

# List.fold_left (fun l x -> List.map (function l -> x :: l) ([] :: l))
    [] [2; 3; 5; 7; 11];;    
- : int list list = [[11]; [11; 7]; [11; 7; 5]; [11; 7; 5; 3]; [11; 7; 5; 3; 2]]
  (* suffices of a list *)

Native-code compiler (ocamlopt)

• documentation

(* welcome.ml *)

let print whatever =
  Printf.printf "Welcome to %s!!!\n" whatever

(* main.ml *)

Welcome.print "OCaml world"

ocamlopt -o main welcome.ml main.ml

Native-code vs Byte-code compiler performance

Benchmark program

(* Takeuchi's Tarai function *)

let rec t x y z =
  if x <= y then y
  else t (t(x - 1) y z) (t (y - 1) z x) (t (z - 1) x y)

let x, y, z = (14, 7, 0);;
Printf.printf "Takeuchi(%d, %d, %d) = ...%t" x y z flush;

Comparison

ocamlc (byte code compiler)

$ ocamlc -o tak tak.ml
$ time ./tak
Takeuchi(15, 8, 0) = ... 15
./tak  72.69s user 0.27s system 99% cpu 1:13.56 total

ocamlopt (native code compiler)

$ ocamlopt -o tak tak.ml
$ time ./tak
Takeuchi(15, 8, 0) = ... 15
./tak  6.46s user 0.04s system 98% cpu 6.564 total

x12 acceleration in ocamlopt!

Lexer generator (ocamllex)

• documentation

Parser generator (ocamlyacc)

• documentation