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camlp4 scope issue
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Date: -- (:)
From: Dmitri Boulytchev <db@t...>
Subject: Re: [Caml-list] camlp4 scope issue
    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?
>>>
>>
>>
>
>