Phillip J. Eby wrote:
> At 10:00 PM 6/1/2005 +0200, Eric Nieuwland wrote:
>> Phillip J. Eby wrote:
>> > -1, too confusing.
>>
>> A matter of taste, I guess. IMHO 'with' secretly handling exceptions
>> is
>> confusing.
>
> It doesn't secretly handle them; it simply gets access to them, which
> is an entirely different thing.
>
> By confusing, I mean that it is not clear from your construct what
> exceptions are caught by the 'except' clause, due to its structural
> layout. It's also not clear whether the __enter__/__exit__ of EXPR
> wrap BLOCK1 only, or both BLOCK1 and BLOCK2. These aspects are
> "confusing" because whatever decision you make about the semantics,
> someone will have to *remember* them, as opposed to being
> unambiguously represented by the block structure.
>
> By contrast, if you remove the except: clause from your construct, it
> is clear that BLOCK1 is what is wrapped, and there is no possible
> confusion about who sees what exceptions. Exceptions inside the block
> are communicated to __exit__, exceptions outside (including those in
> the 'with' statement itself) are not.
OK. This forwarding (is that the proper expression here?) of an
exception to __exit__ is what I meant by 'secretly handling'.
If everybody agrees I'll write
with EXPR as VAR:
try:
BLOCK1
except EXCEPTION:
BLOCK2
instead. Seems a waiste to me, though.
I was thinking about 'try EXPR [as VAR]:' as a 'try' that handles
uncaught exceptions by forwarding it to EXPR's __exit__ method. No
confusion with me.
--eric
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