(+dinov, who just needs to page this in rather than learn it all from scratch)
On Wed, Sep 17, 2014 at 2:18 PM, Stefan Richthofer <stefan.richtho...@gmx.de> wrote: > Dear IronPython community, > > I recently worked on Jython issue 1057 (http://bugs.jython.org/issue1057) and > also improved the current solution of http://bugs.jython.org/issue1634167 a > bit. For these issues, it is very hard for Jython to emulate CPython behavior > due to the fundamentally different GC implementation, so I suspected, > IronPython might have similar problems and wondered how they are solved here. > Since I never used IronPython or .net, I would appreciate answers on a rather > abstract level and apologize that I have no ambition to look into the source > myself. I'm just hoping to find someone (optimally a core-dev), who can > simply answer it and is maybe open for a discussion of solutions. > > My questions are: > - does IronPython support acquired finalizers? > i.e. > class A(): > pass > > def A__del__(): > print "A finalized" > > a1 = A() > A.__del__ = A__del__ > a1 = None > > > Would it output "A finalized" or not? A quick test (on Mono) says "no", but trying with a class that declares __del__ doesn't either, so I'd want to hook up a debugger on Windows to check for sure. I'm not sure if the backing types created by IronPython have finalizers, but I think not (and reading through the RefEmit code will take longer than I have right now.) > In Jython this won't work so easy, because Jython avoids to overwrite the > finalize method for all instances for its expensiveness. So only instances > known to need finalization on creation time will be finalized. AfaIk, > finalizers in .net are as expensive as in Java, so how would this work in > IronPython? > > > - how complete is the support of the gc module? > i.e. > In Jython the support is rather poor; most methods are just implemented as > stubs, i.e. one-liners as > throw Py.NotImplementedError("not applicable to Java GC") > IronPython is about the same: https://github.com/IronLanguages/main/blob/ipy-2.7-maint/Languages/IronPython/IronPython.Modules/gc.cs > gc.collect usually returns the number of collected objects, but Jython just > calls java.lang.System.gc() and returns None. I believe, tracking the number > of collected objects would be possible, but very expensive, so this maybe > could be added as a start-up-flag feature for debugging. How far does > IronPython support this currently? IronPython just returns the number of bytes freed by the call: https://github.com/IronLanguages/main/blob/ipy-2.7-maint/Languages/IronPython/IronPython/Runtime/PythonContext.cs#L3465. - Jeff _______________________________________________ Ironpython-users mailing list Ironpython-users@python.org https://mail.python.org/mailman/listinfo/ironpython-users
