On Thu, Aug 20, 2020 at 09:03:40AM -0400, Random832 wrote:
On Mon, Aug 17, 2020, at 14:00, Christopher Barker wrote:
From an implementation perspective, the  operator is another way to call __getitem__ and __setitem__. And from that perspective, why not have it act like a function call: no arguments, positional arguments, keyword arguments, the whole shebang.
But from a language design perspective, the  operator is a way to "index" a container -- get part of the container's contents. And from this perspective, no index makes no sense.
I think it makes perfect sense. Remember that numpy *currently* has a concept of "no index" [an empty tuple is used for this], it results in a view of the whole array, or the content as a scalar for a 0-dimensional array.
I wouldn't necessarily be taking numpy as the gold standard of good API design.
Treating a missing index as the object itself makes a certain logical sense. Here's a variable with a subscript:
and here it is again with a missing subscript:
So by analogy, we might say that `x` should be treated as just `x`. But honestly that's more likely to be an error, not a feature.
I think that zero dimensional arrays are a pretty dubious concept, but if you did have one, since it has *no dimensions* it cannot contain any content at all.
[I've occasionally been tempted to try the same thing on ctypes objects, incidentally, I think it might be useful to make obj equivalent to obj.value]
And what about all the objects that don't have a .value attribute? What's so special about that attribute that subscripting with a missing subscript should return that attribute rather than some other?