Version française
Home     About     Download     Resources     Contact us    
Browse thread
camlp4 scope issue
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: -- (:)
From: Mike Lin <mikelin@m...>
Subject: Re: [Caml-list] camlp4 scope issue
I would like to take this opportunity to plug ocaml+twt. Relieve your
suffering...
http://people.csail.mit.edu/mikelin/ocaml+twt/

On 10/25/06, Dmitri Boulytchev <db@tepkom.ru> wrote:
>
>     The revised syntax description you are referring to is quite
> informal so I'd rather trust the compiler :)
>     You may restict the scope of a binding in a way its usual done in
> other languages: by
>
>     do {let y = 1 in a}; b; c;
>
>     in revised or by
>
>     (let y = 1 in a); b; c;
>
>     in  standard syntax.
>
>     BR,
>     DB.
>
> > Perhaps I am misunderstanding the meaning of ";" in the revised
> > syntax, however, the 6.2 chapter
> > (http://caml.inria.fr/pub/docs/manual-camlp4/manual007.html) says that:
> >
> > do { e1; e2; e3; e4 }
> >
> > is an iterative sequence of expressions, whereas "let ... in" is
> > reserved for local constructs.
> >
> > If so, wouldn't the scope of y in
> >
> > let y = 1 in do { a; b; c };
> >
> > be different from:
> >
> > let y = 1 in a; b; c;
> >
> > Or else how to we indicate in the *revised syntax* the boundary of the
> > "let ... in" scope?
> >
> > Serge
> >
> > Dmitri Boulytchev wrote:
> >
> >>     That's ok - semicolon does not restict the scope since it plays
> role
> >> of a binary operation, not a statement delimiter. So in your example
> >>
> >>     (); Printf.printf "y should be out of scope, but it's not: y =
> >> %d\n" y
> >>        is a while scope for let-binding.
> >>
> >>     Best regards,
> >>     Dmitri Boulytchev,
> >>     St.Petersburg State University.
> >>
> >>
> >>> Hi,
> >>>
> >>> In the test program below in my understanding the 'y' variable
> >>> should be
> >>> out of scope in the printf statement, but apparently it's not.  The
> >>> compiler version is 3.09.3.
> >>>
> >>> $ cat tst.ml
> >>> value f z = z + 1;
> >>>
> >>> let x = 1 in do {
> >>>   let y = f x in ();
> >>>   Printf.printf "y should be out of scope, but it's not: y = %d\n" y
> >>> };
> >>>
> >>> $ ocamlc -o tst -pp camlp4r tst.ml
> >>> $ ./tst
> >>> y should be out of scope, but it's not: y = 2
> >>>
> >>>
> >>> Any idea why?
> >>>
> >>
> >>
> >
> >
>
> _______________________________________________
> Caml-list mailing list. Subscription management:
> http://yquem.inria.fr/cgi-bin/mailman/listinfo/caml-list
> Archives: http://caml.inria.fr
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
> Bug reports: http://caml.inria.fr/bin/caml-bugs
>