I was a bit confused by the _ until this morning, when I realized it was more powerful than I thought. For example, you can automatically discard any argument of a function like this:

# let a b _ = b + 1;;
val a : int -> ‘a -> int =
# a 8 “carrot”;;
- : int = 9

In this case it was useless, but it could come in handy when you need to pass a function with a certain signature but you don’t want all the arguments.

Or you can use it when assigning values from a tuple:

let (client_sock, _) = accept listen_sock in…

In this case, accept returned a tuple and I only wanted the first value.

So maybe my article about OCaml+SDL is interesting for you:

http://wiki.njh.eu/OCaml_and_SDL

cool blog !!

there you go i said it

let _ = main () ;;

simply discards the unit value returned by evaluating main () ?

I’d say your hello world should be written this way :

let _ =
print_endline “Hello World!”

If you really wan’t a wrapper around that print_endline, you could use :

let main () = print_endline “Hello World!”

let _ = main ()

Adrien

Chris: I’m going to do some further research into OCaml references and get back to you. From what I’ve seen so far they have more in common with C++ pointers than Java. Of course, that’s not to say they’re the *same* as C++ pointers (e.g. from my understanding you can’t increment OCaml references). Obviously I’m the newbie here, this has just been my experience so far. If you can offer me any such examples where OCaml references are similar to those in Java, or where OCaml references deviate entirely from either language it’d be much appreciated.

Thanks very much for your input guys