Replace Whole Object Through Object Method
Bruno Desthuilliers
onurb at xiludom.gro
Mon Jun 26 13:02:37 EDT 2006
digitalorganics at gmail.com wrote:
> How can an object replace itself using its own method?
AFAIK, It can't (but I can be wrong - some guru around ?).
> See the
> following code:
>
> class Mixin:
> def mixin(object, *classes):
> NewClass = type('Mixin', (object.__class__,) + classes, {})
> newobj = NewClass()
> newobj.__dict__.update(object.__dict__)
> return newobj
>
> def isClass(object):
> if 'classobj' in str(type(object)):
> return 1
> elif "'type'" in str(type(object)):
> return 1
> else:
> return 0
> def listClasses():
> classes = []
> for eachobj in globals().keys():
> if isClass(globals()[eachobj]):
> classes.append(globals()[eachobj])
> print eachobj
> return classes
FWIW:
Python 2.4.3 (#1, Jun 3 2006, 17:26:11)
[GCC 3.4.6 (Gentoo 3.4.6-r1, ssp-3.4.5-1.0, pie-8.7.9)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> def dumbfactory():
... class Dumb(object): pass
... class Dummy: pass
... return Dumb, Dummy
...
>>> globals()
{'__builtins__': <module '__builtin__' (built-in)>, '__name__':
'__main__', '__doc__': None, 'dumbfactory': <function dumbfactory at
0x2aaaaab66e60>}
>>> def fun():
... dumb, dummy = dumbfactory()
... return
...
>>> fun()
>>> globals()
{'__builtins__': <module '__builtin__' (built-in)>, '__name__':
'__main__', 'fun': <function fun at 0x2aaaaab66ed8>, '__doc__': None,
'dumbfactory': <function dumbfactory at 0x2aaaaab66e60>}
>>>
Looks like dumb and dummy won't get listed... And also:
>>> class Mymeta(type):
... pass
...
>>> class Foo(object):
... __metaclass__ = Mymeta
...
>>> "'type'" in str(type(globals()['Mymeta']))
True
Looks like this will list metaclasses too... May or may not be a problem...
> def MixInto(Class, Mixin):
You're aware that in this function's scope, the 'Mixin' arg name will
shadow the Mixin class name ? (sorry for asking dumb question).
> if Mixin not in Class.__bases__:
> Class.__bases__ += (Mixin,)
> ------------------------------------------------------------------------
>
> Okay, so the mixin function becomes part of whatever class I choose and
> hence its instances, but the problem is that the way I currently have
> it setup mixin() returns a new object, instead of replacing whatever
> class instance that calls it into that new object. I hope I'm making
> sense here.
>
> Basically what I need is for the method to be able to find out the name
> of the instance, then I can just go to the globals dictionary to do the
> replacement.
>
> Advance thanks to all who can help...
>
Instead of exposing problems with your solution, you may want to expose
the real use case ?
--
bruno desthuilliers
python -c "print '@'.join(['.'.join([w[::-1] for w in p.split('.')]) for
p in 'onurb at xiludom.gro'.split('@')])"
More information about the Python-list
mailing list