Le 14/08/2020 à 16:24, Mark Shannon a écrit :
>
> https://github.com/markshannon/pep622-critique
Hi all,
reading through this made me think of 3 ideas which I think are new [1].
2 of them are about the Value Pattern question, the last one is a small
nit about the Django example.
* the critique points the limitations to the use of pattern matching in
__init__ methods, because Capture Patterns can't assign to dotted names.
Thus the currently proposed dot-based rule is a limitation not just for
Value Patterns, as already heavily discussed, but also for Capture
Patterns. Moreover, this limitation cannot be lifted after the fact if
the __init__ method use-case proves important in the future.
* the critique points that Value Patterns with booleans would need
identity-, not equality-based comparison. This leads to the idea that,
if a special syntax if eventually used for Value Patterns, using the
comparison operator in it might be useful. Thus we could have:
>>> match int_or_boolean: # ok, dubious design!
... case is True: # same as "if int_or_boolean is True:"
... print("boolean true")
... case is False:
... print("boolean false")
... case == ONE: # same as "if int_or_boolean == ONE:"
... print("integer 1")
* the Django example could be written more idiomatically by relying more
on destructuring instead of having a guard:
>>> match value:
... case [first, *_, label := (Promise() | str())]:
... value = value[:-1]
... case _:
... label = key.replace('_', ' ').title()
Cheers,
Baptiste
[1] as in: I skimmed through most of the threads and believe they have
not already been said (famous last words…)
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