On 18/08/20 6:37 am, Jonathan Fine wrote:
if
>>> something[*argv]
is allowed, then what was a syntax error becomes a run-time error.
I don't think so. If argv is empty, this is more akin to
x = ()
something(x)
which we presumably still want to allow.
Opponents of a[] aren't trying to prevent an empty tuple being
passed as an index, only disallow that particular way of spelling
it.
One possible reason for that is because it's not clear whether
it should really mean passing an empty tuple or passing no
positional argument at all.
However, we still have to grapple with that issue if we want to
allow keyword-only indexes, and it seems to me that whatever
answer we come up with should also apply to a[]. So that's not
really an argument against allowing a[].
Another reason put forward is that someone might accidentally
type d[] = something and get an unexpected empty tuple in their
dict. But I don't see why that's such a heinous possibility that
a syntactic restriction is needed to protect us from it. Normal
debugging techniques should be adequate to find it.
So there don't seem to be any real technical arguments against
allowing a[], only ones based on tradition ("we never allow it
before") and emotion ("this looks weird and unfamiliar").
--
Greg
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