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From: Ryan Kelly on 20 Feb 2010 21:51
On Sun, 2010-02-21 at 13:17 +1100, Lie Ryan wrote:
> On 02/21/10 12:02, Stef Mientki wrote:
> > On 21-02-2010 01:21, Lie Ryan wrote:
> >>> On Sun, Feb 21, 2010 at 12:52 AM, Stef Mientki
> <stef.mientki(a)gmail.com> wrote:
> >>>
> >>>> hello,
> >>>>
> >>>> I would like my program to continue on the next line after an uncaught
> >>>> exception,
> >>>> is that possible ?
> >>>>
> >>>> thanks
> >>>> Stef Mientki
> >>>>
> >>>>
> >> That reminds me of VB's "On Error Resume Next"
> >>
> > I think that's what I'm after ...
>
> A much better approach is to use callbacks, the callbacks determines
> whether to raise an exception or continue execution:
>
> def handler(e):
> if datetime.datetime.now() >= datetime.datetime(2012, 12, 21):
> raise Exception('The world has ended')
> # else: ignore, it's fine
>
> def add_ten_error_if_zero(args, handler):
> if args == 0:
> handler(args)
> return args + 10
>
> print add_ten_error_if_zero(0, handler)
> print add_ten_error_if_zero(10, handler)
> print add_ten_error_if_zero(0, lambda e: None) # always succeeds


Or if you don't like having to explicitly manage callbacks, you can try
the "withrestart" module:

http://pypi.python.org/pypi/withrestart/

It tries to pinch some of the good ideas from Common Lisp's
error-handling system.

from withrestart import *

def add_ten_error_if_zero(n):
# This gives calling code the option to ignore
# the error, or raise a different one.
with restarts(skip,raise_error):
if n == 0:
raise ValueError
return n + 10

# This will raise ValueError
print add_ten_error_if_zero(0)

# This will print 10
with Handler(ValueError,"skip"):
print add_ten_error_if_zero(0)

# This will exit the python interpreter
with Handler(ValueError,"raise_error",SystemExit):
print add_ten_error_if_zero(0)



Cheers,

Ryan


--
Ryan Kelly
http://www.rfk.id.au | This message is digitally signed. Please visit
ryan(a)rfk.id.au | http://www.rfk.id.au/ramblings/gpg/ for details

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