namespace dictionaries ok?

Alex Martelli aleaxit at yahoo.com
Wed Oct 26 16:42:19 CEST 2005


Ron Adam <rrr at ronadam.com> wrote:
   ...
>      class namespace(dict):
>          def __getattr__(self, name):
>              return self.__getitem__(name)
   ...
> Any thoughts?  Any better way to do this?

If any of the keys (which become attributes through this trick) is named
'update', 'keys', 'get' (and so on), you're toast; it really looks like
a nasty, hard-to-find bug just waiting to happen.  If you're really
adamant on going this perilous way, you might try overriding
__getattribute__ rather than __getattr__ (the latter is called only when
an attribute is not found "in the normal way").

If you think about it, you're asking for incompatible things: by saying
that a namespace X IS-A dict, you imply that X.update (&c) is a bound
method of X; at the same time, you also want X.update to mean just the
same thing as X['update'].  Something's gotta give...!-)


Alex



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