On 4/1/2021 9:38 PM, Guido van Rossum wrote:
On Thu, Apr 1, 2021 at 2:18 PM Mark Shannon <[email protected]
<mailto:[email protected]>> wrote:
Almost all the changes come from requiring __match_args__ to be a tuple
of unique strings.
The current posted PEP does not say 'unique' and I agree with Guido that
it should not.
Ah, *unique* strings. Not sure I care about that. Explicitly checking
for that seems extra work,
The current near-Python code does not have such a check.
and I don't see anything semantically suspect in allowing that.
If I understand the current pseudocode correctly, the effect of 's'
appearing twice in 'C.__match_args__ would be to possibly look up and
assign C.s to two different names in a case pattern.
I would not be surprised if someone someday tries to do this
intentionally. Except for the repeated lookup, it would be similar to a
= b = C.s. This might make sense if C.s is mutable. Or the repeated
lookups could yield different values.
--
Terry Jan Reedy
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