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From: Gabriel Cardoso <gcardoso.w@gmail.com>
To: Samuel Hornus <samuel.hornus@inria.fr>
Cc: caml-list <caml-list@inria.fr>
Subject: Re: [Caml-list] Problem with Arg.Tuple
Date: Tue, 13 Mar 2012 13:23:52 +0100	[thread overview]
Message-ID: <CADSDpip9xsADudYkWe_wRVQW98bp3e3L7=+qxQbj1YB=z3vd9g@mail.gmail.com> (raw)
In-Reply-To: <070E17B9-F989-4184-A702-7D323710F52B@inria.fr>

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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

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      parent reply	other threads:[~2012-03-13 12:24 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-13 10:49 Gabriel Cardoso
2012-03-13 11:21 ` Samuel Hornus
     [not found] ` <070E17B9-F989-4184-A702-7D323710F52B@inria.fr>
2012-03-13 12:23   ` Gabriel Cardoso [this message]

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