o'caml recursion not working right

[richcash]

I just started O'Caml tonight, so I apologize if it's a bit of an obvious question.

code:

# let rec factorial a =         if a == 1 then a else a * factorial (a-1);; val factorial : int -> int = <fun> # factorial 4;; - : int = 24 # factorial 13;; - : int = -215430144

I'm not sure why my function there is returning a negative value. I know that once the result becomes too big, the function will result 0, but I can't see why it would ever return a negative value like that.

I also tried it for another recursive function and the same thing happened once I got high enough.

code:

# let rec f x power =         if power == 1 then x else x * f x (power-1);; val f : int -> int -> int = <fun> # f 4 3;; - : int = 64 # f 4 15;; - : int = -1073741824

Could someone just tell me if I'm doing something wrong here.
Thanks in advance.

[wtd]

O'Caml's integer datatype has some interesting issues with overflow.

You'll want to use some form of bignum module.

[richcash]

Oh, well that's weird. An error would be better than resulting an incorrect value I think. Too bad it's not more like Ruby (automatically converts back and forth! )

Thanks for clearing that up!

[haskell]

When a program does EXACTLY what its told, debugging and such is quite easy, as you showed and wtd demonstrated. So adding such features would make OCaml less practical in a professional environment, making it unattractive and strictly academic, which it isn't and shouldn't be.

These sorts of things are features, not errors. They are a God-send for programmers and keep us warm inside.

[wtd]

or... O'Caml and Ruby are just different sorts of languages, each of which has advantages and disadvantages.