From mboxrd@z Thu Jan  1 00:00:00 1970
Received: (from weis@localhost) by pauillac.inria.fr (8.6.10/8.6.6) id LAA07987 for caml-redistribution; Mon, 20 Nov 1995 11:20:04 +0100
Received: (from xleroy@localhost) by pauillac.inria.fr (8.6.10/8.6.6) id LAA07901; Mon, 20 Nov 1995 11:16:47 +0100
From: Xavier Leroy <xleroy@pauillac.inria.fr>
Message-Id: <199511201016.LAA07901@pauillac.inria.fr>
Subject: Re: CAML Light system functions etc.
To: jharriso@ra.abo.fi (John Harrison)
Date: Mon, 20 Nov 1995 11:16:47 +0100 (MET)
Cc: caml-list@pauillac.inria.fr, jharriso@ra.abo.fi
In-Reply-To: <199511191552.RAA18448@tanichka.abo.fi> from "John Harrison" at Nov 19, 95 05:52:27 pm
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: weis


> (1) Is there an interface to "tempnam" or something similar? (For creating
> unique temporary filenames). I looked in the "unix" library but couldn't
> find anything -- I think it'd be a convenient addition.

It is a SMOP (Small Matter Of Programming). Here is the function I use:

let temp_file base suffix =
  let rec try_name counter =
    let name = "/tmp/" ^ base ^ string_of_int counter ^ suffix in
    if Sys.file_exists name then try_name (counter + 1) else name
  in try_name (Unix.getpid())

> (2) I'm not really convinced that integrating signal and exception handling
> is a good idea;

Signal handlers registered with Unix.signal are arbitrary functions;
They can raise exceptions, or do anything else a function can do.

However, it is true that there is only one way to abort other
computations from a signal handler, which is to raise an exception.

> it's neither pleasant nor efficient to always have to worry
> about signal exceptions popping up.

Shall I read this as ``I use (try ... with _ -> ...) all the time because
I'm too sloppy to figure out exactly which exceptions I should trap'' ?
That's a dangerous thing to do, since any heap allocation can trigger
the Out_of_memory exception.

> Is it possible to make SIGINT terminate
> the evaluation of the current toplevel phrase, without passing a signal
> exception to the currently executing function?

I'm afraid not. The language has only one non-local control structure:
exceptions.

> (3) Is there some hook to allow a user-defined function to be called after
> the evaluation and printing of each toplevel phrase? This would be nice for
> reporting run statistics etc.

No, there isn't.

Regards,

- Xavier Leroy