I think one thing that should be addressed is how to change the cached value, for example after the setter is called. Having multiple decorators would seem to make this slightly more complicated. If we were using only one, it would be easy to just add a cache property to the decorated function, which the setter could easily deal with. @property(cache=True) def foo(self): return(self.bar * 99) @foo.setter def foo(self, bar): self.bar = bar / 99 del foo.cache # or foo.cache = bar I guess this doesn't actually work anyway because of the way setters are specified, since it would refer to the setter instead of the property. Hmm. Perhaps, since the return value of setters is currently meaingless, it could be written into the cache, or used to specify if the cache should be cleared? Or just clear the cache automatically any time the setter is called. I realize that these ideas would probably introduce excessive overhead and have some other problems, but I think this is something that needs to be figured out before too long, so having some more ideas out there probably won't hurt. - JB On 2009-04-30, spir <denis.spir@free.fr> wrote:
Le Thu, 30 Apr 2009 13:57:07 +1000, Steven D'Aprano <steve@pearwood.info> s'exprima ainsi:
-1 on an extra parameter to property.
+1 on a cache decorator.
It is clear and simple enough to write something like:
@property @cache # or "once" if you prefer the Eiffel name def value(self): pass
I vote +1 for this version. Cache and property are distinct features.
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