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From: Thien-Thi Nguyen <ttn@gnu.org>
To: Panicz Maciej Godek <godek.maciek@gmail.com>
Cc: "guile-user@gnu.org" <guile-user@gnu.org>
Subject: Re: Exceptions that pass continuations
Date: Fri, 19 Jul 2013 15:00:56 +0200	[thread overview]
Message-ID: <8738ra3drr.fsf@zigzag.favinet> (raw)
In-Reply-To: <CAMFYt2Z+_iPSLQnXXa1Nvw9T79DiYsWZxzLf7WPoE-41ZtGyFA@mail.gmail.com> (Panicz Maciej Godek's message of "Fri, 19 Jul 2013 12:39:55 +0200")

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() Panicz Maciej Godek <godek.maciek@gmail.com>
() Fri, 19 Jul 2013 12:39:55 +0200

   and the whole thing can be used as follows

   (let ((resources '()))
     (supply (((release-resource r)
                  (set! r (cons r resources))))
       (let ((r (allocate-resource)))
         (demand 'release-resource r)
         (do-something-constructive-with r)))
     (for-each release-resource resources))

   (of course, this makes little sense if the
   resource is released within the same
   procedure it is allocated, but if the release
   cannot be performed locally, it seems the
   right thing)

   I wonder whether this design pattern has ever
   been used before, or if there are any potential
   flaws with its application.

Maybe i'm missing something about this particular situation, but i
think generally, the open-use-close pattern in the presence of gc is
best handled by SMOBS and guardians.  The resource is "opened" on SMOB
construction, used for some time and then either explicitly "closed"
(and forgotten) or forgotten.  The guardian notes the state (still
open, already closed) of its objects and closes the ones that need it.

In this case, are OpenGL "lights" not amenable to wrapping as a SMOB?

-- 
Thien-Thi Nguyen
   GPG key: 4C807502
   (if you're human and you know it)
      read my lisp: (responsep (questions 'technical)
                               (not (via 'mailing-list)))
                     => nil

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  reply	other threads:[~2013-07-19 13:00 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-19 10:39 Exceptions that pass continuations Panicz Maciej Godek
2013-07-19 13:00 ` Thien-Thi Nguyen [this message]
2013-07-19 13:52   ` Panicz Maciej Godek
2013-07-19 16:14     ` Thien-Thi Nguyen
2013-07-19 14:12   ` Taylan Ulrich B.

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