On 4/24/05, Phillip J. Eby <[EMAIL PROTECTED]> wrote:
> At 09:12 PM 4/24/05 -0600, Steven Bethard wrote:
> >I guess it would be helpful to see example where the looping
> >with-block is useful.
>
> Automatically retry an operation a set number of times before hard failure:
>
> with auto_retry(times=3):
> do_something_that_might_fail()
>
> Process each row of a database query, skipping and logging those that cause
> a processing error:
>
> with x,y,z = log_errors(db_query()):
> do_something(x,y,z)
Thanks for the examples! If I understand your point here right, the
examples that can't be easily rewritten by composing a
single-execution with-block with a for-loop are examples where the
number of iterations of the for-loop depends on the error handling of
the with-block. Could you rewrite these with PEP 288 as something
like:
gen = auto_retry(times=3)
for _ in gen:
try:
do_something_that_might_fail()
except Exception, err: # Pretend "except Exception:" == "except:"
gen.throw(err)
gen = log_errors(db_query())
for x,y,z in gen:
try:
do_something(x,y,z)
except Exception, err: # Pretend "except Exception:" == "except:"
gen.throw(err)
Obviously, the code is cleaner using the looping with-block. I'm just
trying to make sure I understand your examples right.
So assuming we had looping with-blocks, what would be the benefit of
using a for-loop instead? Just efficiency? Or is there something
that a for-loop could do that a with-block couldn't?
STeVe
--
You can wordify anything if you just verb it.
--- Bucky Katt, Get Fuzzy
_______________________________________________
Python-Dev mailing list
Python-Dev@python.org
http://mail.python.org/mailman/listinfo/python-dev
Unsubscribe:
http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
