derived classes and __getattr__
Peter Otten
__peter__ at web.de
Fri Sep 5 04:47:13 EDT 2008
Alexandru Moșoi wrote:
> i'm facing the following problem:
>
> class Base(object):
> def __getattr__(self, attr): return lambda x: attr + '_' + x
>
> def dec(callable):
> return lambda *args: 'dec_' + callable(*args)
>
> class Derived(Base):
> what_so_ever = dec(Base.what_so_ever) # wrong, base doesn't have
> what_so_ever
> mumu = dec(Base.mumu) # wrong, base
> doesn't have mumu
>
> any idea how to do this?
__getattr__() is defined in the class to create instance attributes on the
fly. If you want class attributes you have to put the __getattr__() method
into the class of the class, or "metaclass":
class Base(object):
class __metaclass__(type):
def __getattr__(self, attr):
return lambda self, x: attr + '_' + x
def dec(callable):
return lambda *args: 'dec_' + callable(*args)
class Derived(Base):
what_so_ever = dec(Base.what_so_ever)
d = Derived()
print d.what_so_ever("42")
I don't see how you can turn this into something useful...
Peter
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