call ocaml from R

["Peng Zhang" <pczhang@gmail.com>]

Hi folks,

I need some help from you. What I want to do is that my main program
is in R and I want to implement part of it with ocaml.

The following is an example.

/* mysin.R */
dyn.load("mysin.so")
mysin <- function(x)
  .C("mysin", as.double(x), r = double(1))$r

/* mycode.ml */
let sin_ml x = sin x
let _ = Callback.register "sin_ml" sin_ml

I want to use sin defined in mycode.ml in mysin.R

Then I write the following stub code

/* mysin.c */
#include <caml/mlvalues.h>
#include <caml/memory.h>
#include <caml/alloc.h>
#include <caml/custom.h>
#include <caml/callback.h>

void mysin(double * x, double * r){
  value * closure_f;
  caml_startup(NULL);
  closure_f = caml_named_value("sin_ml");
  *r = Double_val(caml_callback(*closure_f, caml_copy_double(*x)));
}

It isn't working right now. What I am not sure about is what to put in
caml_startup.

Can somebody help with me this? Thank you very much!

Best,
Peng