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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Newsgroups: comp.lang.ada
Subject: Re: Files and controlled types
Date: Mon, 10 Mar 2008 18:45:38 -0400
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Date: 2008-03-10T18:45:38-04:00
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Eric Hughes <eric.eh9@gmail.com> writes:

> On Mar 8, 3:22 pm, Maciej Sobczak <see.my.homep...@gmail.com> wrote:
>> File types are not Controlled.
> [...]
>> I would think that types associated with external resources should be
>> Controlled to facilitate resource management in the presence of
>> exceptions [...]
>
> The current file types are at an analogous abstraction level to the
> standard C library.  Ada could also use a file type analogous to that
> in the standard C++ library.  Both are relevant.

True.

Note that Ada's file handling predates finalization.  And Adam Beneschan
showed why it would be hard to "fix" things in an upward compatible way.

It's not hard to write your own file type, so that initialization opens
the file, and finalization closes it.  You can pass the file name as a
discriminant to the File_Type, or (now that Ada supports limited
constructor functions) you can use one or more functions to "construct"
an open file from a name or from whatever else you like.

- Bob