From: David House <dhouse@janestreet.com>
To: "Török Edwin" <edwin+ml-ocaml@etorok.net>
Cc: OCaml Mailing List <caml-list@inria.fr>
Subject: Re: [Caml-list] Lazyness and exceptions
Date: Thu, 22 Nov 2012 10:37:23 +0000 [thread overview]
Message-ID: <CAK=fH+jJF4FoW1zrFBem6cLhkmdA8FpU0ofmFdrAJTkECFU1dw@mail.gmail.com> (raw)
In-Reply-To: <50ADFF81.4000300@etorok.net>
In other words: what alternative semantics would you actually want?
On Thu, Nov 22, 2012 at 10:33 AM, Török Edwin <edwin+ml-ocaml@etorok.net> wrote:
> On 11/22/2012 12:29 PM, Jean-vincent.Loddo@lipn.univ-paris13.fr wrote:
>> Hello,
>>
>> I have observed a strange behaviour of lazy values when an exception is raised. Here a minimal code that reproduces the behaviour:
>>
>> # let action =
>> let thunk () =
>> Printf.printf "aaa\n";
>> failwith "bbb"
>> in
>> lazy (thunk ());;
>>
>> val action : unit lazy_t = <lazy>
>>
>> # Lazy.force action ;;
>> aaa
>> Exception: Failure "bbb".
>>
>> # Lazy.force action ;;
>> Exception: Failure "bbb".
>>
>> The lazy value seems to be (correctly) not re-evaluated but the exception is (strangely) raised again. Why does this happen?
>
> Its the documented behavior:
> http://caml.inria.fr/pub/docs/manual-ocaml/libref/Lazy.html
>
> Unfortunately the original backtrace will be lost.
>
> --Edwin
>
> --
> Caml-list mailing list. Subscription management and archives:
> https://sympa.inria.fr/sympa/arc/caml-list
> Beginner's list: http://groups.yahoo.com/group/ocaml_beginners
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next prev parent reply other threads:[~2012-11-22 10:37 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-11-22 10:29 Jean-vincent.Loddo
2012-11-22 10:33 ` Török Edwin
2012-11-22 10:37 ` David House [this message]
2012-11-22 10:57 ` Jean-vincent.Loddo
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