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From: Malcolm Matalka <mmatalka@gmail.com>
To: Nicolas Ojeda Bar <n.oje.bar@gmail.com>
Cc: Goswin von Brederlow <goswin-v-b@web.de>,  caml-list@inria.fr
References: <20150806094030.GE16477@frosties>
	<CAPunWhApy98_3Oyb+FkQLr7xdETAu33YpzGk2R6m9=cPBQF2tg@mail.gmail.com>
Date: Thu, 06 Aug 2015 19:50:38 +0000
In-Reply-To: <CAPunWhApy98_3Oyb+FkQLr7xdETAu33YpzGk2R6m9=cPBQF2tg@mail.gmail.com>
	(Nicolas Ojeda Bar's message of "Thu, 6 Aug 2015 11:48:07 +0200")
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Subject: Re: [Caml-list] Destructive use of file descriptors

Nicolas Ojeda Bar <n.oje.bar@gmail.com> writes:

> Hi,
>
> No magic needed in OCaml:
>
>   let with_open path f =
>     let oc = open_out path in
>     match f oc with
>     | x -> close_out_noerr oc; x
>     | exception e -> close_out_noerr oc; raise e
>
> and then use it as
>
>   with_open "foo" (fun oc -> output_string oc str)
>
> Cheers
>
> Nicolas
>

The weakness with this (which I'm not sure if Python offers protection)
is returning something that references the file created.  It can lead to
some confusing error messages.