"Greg Falcon" <[EMAIL PROTECTED]> wrote:
[snip]
> I'm coming from a philosophy, though, that believes any time a
> syntactic construct creates a local binding and a new suite to use it
> in, the binding shouldn't escape that suite. Yes, I'm really talking
> about 'for', and I know this is probably a controversial view. But
> don't the same arguments apply? (It's probably an error to use the
> variable outside the suite, and if you really need to, you could be
> explicit and store another reference to it in a separate local.)
Yeah, I like reusing the variable names bound in a for loop. And unless
we are going to attempt to simplify the <assignment target> in...
for <assignment target> in ...:
...
to only be a bare name, and not things like 'i, (j, k)', then removing
names is going to be difficult. I would be -1 on any changes to the for
loop syntax (value unpacking is so darn convenient), and without syntax
change, then variable bleeding semantics would be difficult to change
(which I am also -1 on).
> re = get_resource()
> ...
> try:
> something()
> except RareException as re:
> ... # handle it
> ...
> re.use_resource()
>
> Which *appears* to work fine most of the time, but when the
> RareException is raised and handled, suddenly the use_resource() line
> generates a surprising UnboundLocalError. These are the sort of
> things that should be caught ahead of time if possible.
According to the translation rules Colin has previously provided...
re = get_resource()
...
try:
something()
except RareException as re:
...
...
re.use_resource()
is translated into...
re = get_resource()
...
try:
try:
something()
except RareException:
re = <current exception>
...
finally:
re = None
del re
...
re.use_resource()
That is, the 're = None; del re' stuff is executed regardless of whether
the except body is executed. The user would be notified right away.
- Josiah
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