() Panicz Maciej Godek () 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