Another idea:
Instead of new dunders, have a class attribute that flags the
existing ones as taking positional and keyword arguments.
class ILikeMyIndexesPositional:
__newstyleindexing__ = True
def __getitem__(self, i, j, spam = 42):
...
Advantages:
No new dunders or type slots required.
Disadvantages:
Code that expects to be able to delegate to another object's
item dunder methods could break. There are two ways that existing
code might perform such delegation:
def __getitem__(self, index):
return other_object[index]
def __getitem__(self, index):
return other_object.__getitem__(index)
Neither of these will work if index is a tuple and other_object
takes new-style indexes, because it will get passed as a single
argument instead of being unpacked into positional arguments.
The only reliable way to perform such delegation would be
__newstyleindexing__ = True
def __getitem__(self, *args, **kwds):
return other_object[*args, **kwds]
but that requires the delegating object to be aware of
new-style indexing.
So having thought it through, I'm actually anti-proposing this
solution.
--
Greg
--
Greg
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