This paper explains how to implement them and gives example code: http://community.haskell.org/~simonmar/papers/weak.pdf I'm not aware of a package that does it for you, but I implemented one as part of my own work so that may be able to provide another example. Cheers, -Trev On 11/08/2013, at 6:03 AM, Alessandro Vermeulen wrote:

There is supposed to be some weak hash map implementation somewhere.

However, if you can't find it you can easily create it yourself. However, you will need to use the map in IO so I suggest that you use the hashtables[1] package in combination with the weak pointers mentioned by Erik.

- Alessandro

[1]: http://hackage.haskell.org/package/hashtables

On 10 aug. 2013, at 21:08, Erik Hesselink wrote:

...

I'm not sure, but there are weak pointer [0], though I have never used them.

Erik

[0] http://www.haskell.org/ghc/docs/latest/html/libraries/base/System-Mem-Weak.h...

On Sat, Aug 10, 2013 at 7:13 PM, Aleksey Uymanov wrote:

...

Hello, haskellers.

Is there any package implementing magic hash tables weak in value? I mean when the value is garbage collected, then this key+value authomatically removes from the hash table.

-- Aleksey Uymanov

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

---

Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe