Thanks, I get it now !

Cheers

Gabriel

2012/3/13 Samuel Hornus <samuel.hornus@inria.fr>

>
> On Mar13, 2012, at 11:49 , Gabriel Cardoso wrote:
>
> > Dear list,
> >
> > I have empty arguments when using Arg.Tuple with references. This
> minimalist example illustrates my problem :
> >
> > let f a b =
> >   print_endline a;
> >   print_endline b
> >
> > let s = ref ""
> >
> > let speclist = [(
> >   "-a",
> >   Arg.Tuple [
> >     Arg.Set_string s;
> >     Arg.String (f !s) (* !s is empty !!! *)
>
> Here, the value of !s is empty when the (f !s) is evaluated…
> you shoud pass the whole reference as argument :
> Arg.String(f s)
> and
> let f a b = print_endline !a; print_endline b
>
> >     (* Arg.String (fun ss -> f !s ss) (\* Works just fine ... why ? *\)
> *)
>
> why ? because the !s here is evaluated only later, whenthe anonymous
> function is applied.
> --
> Sam