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fnbr

Well, that explains a lot! I'm embarrassed I never got past that.

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Don't feel too bad about it. The official OCaml tutorial is also confused:

http://ocaml.org/learn/tutorials/structure_of_ocaml_programs...

(someone really should go through these tutorials and fix the various misleading parts)

Basically, the rule is to use "let () = ..." for your main block / top-level code and don't use ";;" ever.

For reference, here is the tutorial's example reformatted in a more reasonable way:

    open Random
    open Graphics

    let rec iterate r x_init i =
        if i = 1 then x_init
        else
            let x = iterate r x_init (i - 1) in
            r *. x *. (1.0 -. x)

    let main () =
        self_init ();
        open_graph " 640x480";

        for x = 0 to 639 do
            let r = 4.0 *. (float_of_int x) /. 640.0 in
            for i = 0 to 39 do
                let x_init = Random.float 1.0 in
                let x_final = iterate r x_init 500 in
                let y = int_of_float (x_final *. 480.) in
                Graphics.plot x y
            done
        done;

        ignore (read_line ())

    let () = main ()

The trouble with Ocaml is that you will probably get something like:

  $ ocaml o.ml
   File "o.ml", line 2, characters 0-13:
   Error: Unbound module Graphics

And after you've googled for a while and had done:

  sudo apt-get install liblablgl-ocaml-dev

The thing would install 23(!) packages. And after that you will get:

  $ ocaml o.ml
   Exception: Graphics.Graphic_failure "fatal I/O error".

After which, if you've been in the industry for a decade or two, you will probably decide that you'd better stop wasting your time on that particular language. Besides. It just looks ugly. Almost as ugly as perl.

The Graphics module is a core Ocaml library that is always available. In order to use it, it must be linked on the command line, similar to many other languages. Installing an unrelated OpenGL binding didn't magically make "ocaml o.ml" work. Based on this and the obvious trolling of your final paragraph, I'm hesitant to believe anything you said is true.

Seriously. You are so biased that it is easier for you to believe that other people are downright lying than to accept inconvenient truth. I was running it in the interpreted mode. Isn't that how one is supposed to run tutorials code? And obviously I've added the following:

  #load "graphics.cma";;

into the file first. And forgot about it, when writing the post. So no magic here. "Beautiful" syntax by the way.

And no, I wasn't trolling. I just wanted to see what that recursion would do. The code is not exactly crystal clear there, with names like start_x and such. But it really did not work. And the syntax is really ugly. And you can believe what you like.

Dont judge syntax when you are new to a language. Few syntaxes have the tendency to never grow on you, but it is surprising how most do, even when your first impressions were pretty bad. Remarkable abilities of the human brain !

Does that mean that K syntax could grow on me? http://en.wikipedia.org/wiki/K_(programming_language)

For this old C programmer, Python proved to have the most friendly syntax.

Tried it here and it worked, both on Arch Linux with OCaml 4.01.0 and a clean Ubuntu/12.04 with OCaml 3.12.1:

$ ocaml graphics.cma test.ml

Debian splits OCaml into two packages: ocaml-nox (no X) and ocaml (everything). Make sure you're not using the nox version, and make sure you have an X server available (i.e. you're not running it on a headless server or something).

Still, "fatal I/O error" is a terrible error message.

Ocaml 3.12.1; Ubuntu 13.10. X server is available, Desktop is MATE 1.6.0, OpenGL also seems to work (glxgears works).

Pull requests welcome:

https://github.com/ocaml/ocaml.org/tree/master/site/learn/tu...

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