[Haskell-cafe] Explicit garbage collection
ekmett at gmail.com
Wed Jan 6 15:21:05 EST 2010
You probably just want to hold onto weak references for your 'isStillNeeded'
Otherwise the isStillNeeded check itself will keep you from garbage
On Wed, Jan 6, 2010 at 9:39 AM, Miguel Mitrofanov <miguelimo38 at yandex.ru>wrote:
> I'll take a look at them.
> I want something like this:
> refMaybe b dflt ref = if b then readRef ref else return dflt
> refIgnore ref = return "blablabla"
> refFst ref =
> (v, w) <- readRef ref
> return v
> test =
> a <- newRef "x"
> b <- newRef 1
> c <- newRef ('z', Just 0)
> performLocalGC -- if necessary
> x <- isStillNeeded a
> y <- isStillNeeded b
> z <- isStillNeeded c
> u <- refMaybe y "t" a -- note that it wouldn't actually read "a",
> -- but it won't be known until runtime.
> w <- refIgnore b
> v <- refFst c
> return (x, y, z)
> so that "run test" returns (True, False, True).
> Dan Doel wrote:
>> On Wednesday 06 January 2010 8:52:10 am Miguel Mitrofanov wrote:
>>> Is there any kind of "ST" monad that allows to know if some STRef is no
>>> longer needed?
>>> The problem is, I want to send some data to an external storage over a
>>> network and get it back later, but I don't want to send unnecessary
>>> I've managed to do something like that with weak pointers,
>>> System.Mem.performGC and unsafePerformIO, but it seems to me that
>>> GC every time is an overkill.
>>> Oh, and I'm ready to trade the purity of runST for that, if necessary.
>> You may be able to use something like Oleg's Lightweight Monadic Regions
>> to get this effect. I suppose it depends somewhat on what qualifies a
>> reference as "no longer needed".
>> I'm not aware of anything out-of-the-box that does what you want, though.
>> -- Dan
>> Haskell-Cafe mailing list
>> Haskell-Cafe at haskell.org
> Haskell-Cafe mailing list
> Haskell-Cafe at haskell.org
-------------- next part --------------
An HTML attachment was scrubbed...
More information about the Haskell-Cafe