Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #86167

Re: Design thought for callbacks

References (8 earlier) <mailman.19029.1424639844.18130.python-list@python.org> <87wq39hbq1.fsf@elektro.pacujo.net> <cfkaran2@gmail.com> <0443FBDF-9FD0-492E-8486-03EBD0972C04@gmail.com> <201502222229.t1MMT7Dn029607@fido.openend.se>
Date 2015-02-23 09:41 +1100
Subject Re: Design thought for callbacks
From Chris Angelico <rosuav@gmail.com>
Newsgroups comp.lang.python
Message-ID <mailman.19037.1424644873.18130.python-list@python.org> (permalink)

Show all headers | View raw

On Mon, Feb 23, 2015 at 9:29 AM, Laura Creighton <lac@openend.se> wrote:
> But that is not so surprising.  How many people use WeakSets for
> _anything_?  I've never used them, aside from 'ooh! cool shiny
> new language feature!  Let's kick it around the park!'  That people
> aren't familiar with WeakSets doesn't mean all that much.

I haven't used weak *sets*, but I've used weak *mappings* on occasion.
It's certainly not a common thing, but they have their uses. I have a
MUD which must guarantee that there be no more than one instance of
any given room (identified by a string that looks like a Unix path),
but which will, if it can, flush rooms out of memory when nothing
refers to them. So it has a mapping from the path strings to the
instances, but with weak refs for the instances; if anything else is
referring to that instance (eg a player character in the room), it'll
hang around, and any time anyone else needs that room, they'll get the
same instance back from the mapping; but any time the garbage
collector notices that a room can be disposed of, it will be.

Definitely not common though.

ChrisA

Back to comp.lang.python | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-21 09:07 -0500
  Re: Design thought for callbacks Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-22 04:27 +1100
    Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-22 08:13 -0500
      Re: Design thought for callbacks Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2015-02-24 00:31 +1100
    Re: Design thought for callbacks Ethan Furman <ethan@stoneleaf.us> - 2015-02-22 13:02 -0800
    Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-22 16:17 -0500
      Re: Design thought for callbacks Marko Rauhamaa <marko@pacujo.net> - 2015-02-22 23:34 +0200
        Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-22 17:09 -0500
        Re: Design thought for callbacks Laura Creighton <lac@openend.se> - 2015-02-22 23:29 +0100
        Re: Design thought for callbacks Chris Angelico <rosuav@gmail.com> - 2015-02-23 09:41 +1100
        Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-23 06:47 -0500
        Re: Design thought for callbacks "Frank Millman" <frank@chagford.com> - 2015-02-23 14:29 +0200
        Re: Design thought for callbacks Cem Karan <cfkaran2@gmail.com> - 2015-02-24 06:00 -0500

csiph-web