>>>>> Darren Dale <dsdal...@gmail.com> (DD) wrote:
>DD> On Apr 11, 2:15 pm, Darren Dale <dsdal...@gmail.com> wrote:
>>> I am working on a project that provides a high level interface to hdf5
>>> files by implementing a thin wrapper around h5py. I would like to
>>> generalize the project so the same API can be used with other formats,
>>> like netcdf or ascii files. The format specific code exists in File,
>>> Group and Dataset classes, which I could reimplement for each format.
>>> But there are other classes deriving from Group and Dataset which do
>>> not contain any format-specific code, and I would like to find a way
>>> to implement the functionality once and apply uniformly across
>>> supported formats. This is really abstract, but I was thinking of
>>> something along the lines of:
>>>
>>> format1.Group # implementation of group in format1
>>> format2.Group # ...
>>> Base.DerivedGroup # base implementation of DerivedGroup, not directly
>>> useful
>>> format1.DerivedGroup = Base.DerivedGroup(format1.Group) # useful
>>> format2.DerivedGroup = Base.DerivedGroup(format2.Group) # useful
>>>
>>> Could anyone please offer a comment, is this an appropriate use of
>>> metaclassing, or is there maybe an easier/better alternative?
>DD> I don't fully understand metaclasses, but I think I have convinced
>DD> myself that they are not what I was looking for. I think this will do
>DD> what I want it to:
>DD> class Group1(object):
>DD> def origin(self):
>DD> return "Group1"
>DD> class Group2(object):
>DD> def origin(self):
>DD> return "Group2"
>DD> def _SubGroup(superclass):
>DD> class SubGroup(superclass):
>DD> pass
>DD> return SubGroup
>DD> SubGroup = _SubGroup(Group2)
What is the difference of this with:
class SubGroup(Group2):
pass
?
>DD> sub_group = SubGroup()
>DD> print sub_group.origin()
>From your description I find it very difficult to understand what you
want. But I have some feeling that multiple inheritance may be something
you could use.
--
Piet van Oostrum <p...@cs.uu.nl>
URL: http://pietvanoostrum.com [PGP 8DAE142BE17999C4]
Private email: p...@vanoostrum.org
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