ocaml.jl's Introduction

OCaml.jl

This package enables you to generate Julia bindings for OCaml libraries with no boilerplate.

How to build the example

To build and run the example, type the following at the root of this repo:

make testjl

How this works

In examples/libocaml/api.mli, we find the following function declaration:

val evaluate: expr -> int

From this signature, the following C wrapper is generated automatically:

value* evaluate(value *x0) {
  static const value *_f = NULL;
  if (_f == NULL) _f = caml_named_value("evaluate");
  value *_r = malloc(sizeof(value));
  *_r = caml_callback_exn(*_f, *x0);
  if (Is_exception_result(*_r)) {
    caml_last_exception = Extract_exception(*_r);
    caml_register_generational_global_root(&caml_last_exception);
    free(_r);
    return NULL;
  }
  else {
    caml_register_generational_global_root(_r);
    return _r;
  }
}

Also, the following Julia stub is generated:

@caml evaluate(::Caml{:expr}) :: Caml{:int}

where the @caml macro expands to:

function evaluate(e)
  e = convert(Caml{:expr}, e)
  GC.@preserve e begin
    ptr = ccall((:evaluate, OCAML_LIB), Ptr{Cvoid}, (Ptr{Cvoid},), e.ptr)
    return tojulia(Caml{:int}(ptr))
  end
end

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