[Python-Dev] Weak references

[Christopher Petrilli]

Fred L. Drake, Jr. [fdrake@acm.org] wrote:
> 
> Guido van Rossum writes:
>  > Yes, definitely.  Weak dicts are sometimes needed for situations where
>  > a regular dict would keep objects alive forever.  E.g. we were made
>  > aware of a "leak" in JPython that could only be fixed with weak dicts:
>  > the Swing wrapper code has a global dict mapping widgets to callback
> 
>   That's a perfect example.  I've started working on some text
> describing the motivation; hopefully I'll have that fleshed out and
> checked in later this week.

Another example is some of the things in Zope use back-references for
ease of traversability (or worse keep weird counts hanging around).
Alot of these are negated by ZODB's ability to break cycles, but... a
lot of data structures would be hugely better from an architecture
perspective if we had a native weak reference.  

Chris
-- 
| Christopher Petrilli
| petrilli@amber.org