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From: Jon Harrop <jdh30@cam.ac.uk>
To: caml-list@inria.fr
Subject: Re: [Caml-list] Strange syntax behavior
Date: Tue, 1 Jun 2004 18:30:32 +0100	[thread overview]
Message-ID: <200406011830.32881.jdh30@cam.ac.uk> (raw)
In-Reply-To: <20040601171354.GA16495@excelhustler.com>


> In the case of if...then...else, the else clause appears to consume only
> the first statement following.

Yes, it is looking for an expression:

if true then
  p "yes"
else
  p "no";
p "done";;

You may have meant:

if true then
  p "yes"
else
  begin
    p "no";
    p "done"
  end;;

> With try..with, the with clause appears 
> to consume everything it possibly can, despite even attempts to stop
> that with a begin..end clause.

Yes, it is looking for pattern matches.

try
  p "test"
with
  Not_found ->
    begin
      p "exc";
    end;
    p "done";;

You probably meant:

begin
  try
    p "test"
  with
    Not_found ->
      p "exc";
end;
p "done";;

> Is this a bug or a feature?  If a feature, why is this so?  the
> try..with behavior seems highly misleading.

I got a feeling for how these sorts of things work by looking at the 
indentation style (in emacs). It's fairly obvious that pattern matches 
(including "try ... with ..." as well as just "match ... with ...") need 
either brackets or "begin ... end" to nest them as, without this, the 
compiler couldn't tell which pattern was matching which match.

Cheers,
Jon.

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  reply	other threads:[~2004-06-01 17:31 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-06-01 17:13 John Goerzen
2004-06-01 17:30 ` Jon Harrop [this message]
2004-06-01 17:40 ` Kenneth Knowles
2004-06-01 17:44 ` Christophe TROESTLER
2004-06-01 17:55 ` skaller
2004-06-02  8:31 ` Hendrik Tews
2004-06-02  8:35 ` Richard Jones

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