Re: [Python-Dev] Cached Property Pattern
It may have been discussed before, but there does not seem to have been any resolution on the issue. Am I missing something or did the discussion just kind of stop, with no solution or agreement ever reached? In which case, reviving the question is not a bad idea, is it? On 12/29/06, Oleg Broytmann [EMAIL PROTECTED] wrote: http://mail.python.org/pipermail/python-dev/2005-September/056782.html On Fri, Dec 29, 2006 at 02:40:05AM -0500, Calvin Spealman wrote: To this end, should a cachedproperty builtin be included to do this The issue was discussed a year ago: http://mail.python.org/pipermail/python-dev/2005-September/056782.html http://mail.python.org/pipermail/python-dev/2005-October/057120.html Oleg. -- Oleg Broytmannhttp://phd.pp.ru/[EMAIL PROTECTED] Programmers don't die, they just GOSUB without RETURN. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/ironfroggy%40gmail.com -- Read my blog! I depend on your acceptance of my opinion! I am interesting! http://ironfroggy-code.blogspot.com/ ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Cached Property Pattern
On Fri, Dec 29, 2006 at 09:55:46AM -0500, Calvin Spealman wrote: It may have been discussed before, but there does not seem to have been any resolution on the issue. Am I missing something or did the discussion just kind of stop, with no solution or agreement ever reached? In which case, reviving the question is not a bad idea, is it? I don't remember any resolution. I think submitting a small module to the patch tracker would be the simplest way to revive the discussion. On 12/29/06, Oleg Broytmann [EMAIL PROTECTED] wrote: http://mail.python.org/pipermail/python-dev/2005-September/056782.html http://mail.python.org/pipermail/python-dev/2005-October/057120.html Oleg. -- Oleg Broytmannhttp://phd.pp.ru/[EMAIL PROTECTED] Programmers don't die, they just GOSUB without RETURN. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Cached Property Pattern
On Friday 29 December 2006 10:50, Oleg Broytmann wrote: I don't remember any resolution. I think submitting a small module to the patch tracker would be the simplest way to revive the discussion. We have a handful of interesting descriptors we use for Zope 3 development: http://svn.zope.org/Zope3/trunk/src/zope/cachedescriptors/ I find I use the Lazy property quite a bit in short-lived contexts (a single web request); this sounds very much like what's being described here. The readproperty is probably better when the computation isn't so expensive and the value may need to be re-computed frequently anyway. -Fred -- Fred L. Drake, Jr. fdrake at acm.org ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
[Python-Dev] Cached Property Pattern
A very common pattern in using properties is as follows: class Foo(object): @property def c(self): if not hasattr(self, '_c'): self._c = some_operation(self.a, self.b) return self._c Basically, the common usage is to only calculate a properties value once, and to reuse the result for every lookup after that. This is so common, that it seems most of my uses of property come in this form. To this end, should a cachedproperty builtin be included to do this automatically? Optionally, it might automatically include a default fset (change the cached value) and fdel (remove the cached value, to be regenerated next time). I will contribute code, if such a patch would be accepted. PS - It seems I am taking over the python-dev summaries, but the holidays have interfered with those duties! I apologize, and promise they will come shortly. -- Read my blog! I depend on your acceptance of my opinion! I am interesting! http://ironfroggy-code.blogspot.com/ ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
