I would rewrite your examples using try/finally:
try:
try:
os.unlink('missing.txt')
finally:
some
other
code
except OSError as exc:
do_something()
It's differently than yours, because it catchs OSError on "some; other; code".
Sometimes, I write it differently by copying the cleanup code:
try:
os.unlink('missing.txt')
cleanup()
except OSError as exc:
cleanup()
do_something()
(Yeah, it's ugly to duplicate code.)
Victor
2013/10/15 R. David Murray <rdmur...@bitdance.com>:
> You wouldn't use trap/as for that. Instead you use it to replace this:
>
> exc = None
> try:
> os.unlink('missing.txt')
> except OSError as exc:
> pass
> some
> other
> code
> if exc is not None:
> do_something()
>
> with:
>
> with trap(OSError) as cm:
> os.unlink('missing.txt')
> some
> other
> code
> if cm.exc is not None:
> do_something()
>
> which saves you *three* lines, not just two :)
>
> Of course in real life, in order for 'some other code' really be the
> best way to organize this snippet, you're going to be doing something
> more complicated than catching OSError from an unlink call.
>
> If this is accepted, I do *not* expect to see this in real code very
> often at all. The main motivation for it is to make the semantics
> of the context manager clearer, and as a bonus make it work like
> assertRaises, which is our existing stdlib context manager that traps
> exceptions.
>
> I'd be happy with 'trap' or 'catch' without 'as' support, but the
> names make more sense if the exception is actually available after
> it is trapped/caught.
>
> --David
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