On Tue, Jan 4, 2022 at 3:32 PM elvis kahoro <[email protected]> wrote:
>>
>> Reading between the lines, I *think* that you want the match statement
>> to catch the exception that you get when the attribute lookup fails, am
>> I right?
>
> Yes!
>
> I was hoping there could be some syntax to extend pattern matching to handle
> exceptions such that we could handle patterns with multiple types of
> exceptions like so:
>
> match this_raises_an_exception, this_raises_another_exception:
> case AttributeError, TypeError:
> print("catches attribute and type errors")
> case AttributeError, AttributeError:
> print("catches attribute and attribute")
> case Exception, Exception:
> print("catches the remaining exceptions")
> case x, y:
> print(f"{x} and {y}")
> case _, _:
> print("everything else")
>
> Any thoughts on this kind of syntax?
> Maybe the author could explicitly distinguish that an exception might be
> raised by using with Exception like so:
>
> match this_raises_an_exception, this_raises_another_exception with Exception:
>
Question: Why? What's wrong with the existing syntax?
Just because match/case syntax exists, that doesn't mean it has to be
used for everything that selects different options.
Exceptions are almost exclusively matched by type, nothing else, and
we already have a very good syntax for doing that. The only situation
where you'd want any other sort of exception matching is when it's a
single type that carries multiple causes of error:
try:
...
except OSError[errno.EEXIST]:
...
But as you can see here, this could easily be accomplished using the
existing syntax, if we needed a way to do it (the use-cases are
uncommon, given that we have eg FileNotFoundError).
When, in production code, have you *ever* needed to match on two
different exceptions at once?
ChrisA
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