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Date: -- (:)
From: Vitaly Lugovsky <vsl@o...>
Subject: [Caml-list] let rec

 For a closure-driven "compilers" I have to use for
a recursion something like this:

    let xprs = ref (fun _ -> Lnil) in
    let f (il,al,ht) =
      let il2 = Array.make (n2+1) Lnil in
      acopy il il2;
      Array.iteri (fun i x -> il2.(all.(i)) <- x) al;
      !xprs (il2,anul,ht)
    in xprs :=
      (Hashtbl.replace ht name (CTfun(f)); (* Insert f into the env2
                                              environment *)
       compile_exprs env2 exprs);
    f

 It's not so funny. Why I can't write it using let rec:

    let rec f (il,al,ht) =
      let il2 = Array.make (n2+1) Lnil in
      acopy il il2;
      Array.iteri (fun i x -> il2.(all.(i)) <- x) al;
      xprs (il2,anul,ht)
    and xprs =
      (Hashtbl.replace ht name (CTfun(f));
       compile_exprs env2 exprs) in
    f

 Sure, let rec construction should be much less restrictive.

 And, another one question: does ocaml compiler really eliminates
unused variables from the closure environment?

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