Conditional except: blocks

[Robert Brewer]

I don't have a quesiton or problem, I just figured some of you would
enjoy the somewhat bizarre logic of the snippet I just wrote for a CGI
request dispatcher:

try:
return nextHandler(arg s)
except (None, Exception)[self.trapErrors], exc:
if page == u'-Error':
raise exc
else:
return self.handle_err or(exc, scriptWithPath)

If self.trapErrors is True, all exceptions (which subclass Exception)
get trapped, otherwise, no exceptions are trapped. Spiffy. :)


FuManChu

[Aahz]

Re: Conditional except: blocks

In article <mailman.27.107 3065446.12720.p ython-list@python.org >,
Robert Brewer <fumanchu@amor. org> wrote:[color=blue]
>
>I don't have a quesiton or problem, I just figured some of you would
>enjoy the somewhat bizarre logic of the snippet I just wrote for a CGI
>request dispatcher:
>
>try:
> return nextHandler(arg s)
>except (None, Exception)[self.trapErrors], exc:
> if page =3D=3D u'-Error':
> raise exc
> else:
> return self.handle_err or(exc, scriptWithPath)
>
>If self.trapErrors is True, all exceptions (which subclass Exception)
>get trapped, otherwise, no exceptions are trapped. Spiffy. :)[/color]

That's pretty sick. If you really need to do that, here's a more
Pythonic approach:

# This goes at beginning of program
# or maybe at class/instance initialization
if trapErrors:
exceptTuple = (Exception,)
else:
exceptTuple = (None,)

# some time later
try:
return nextHandler(arg s)
except exceptTuple, exc:
# Handle exception
--
Aahz (aahz@pythoncra ft.com) <*> http://www.pythoncraft.com/

Weinberg's Second Law: If builders built buildings the way programmers wrote
programs, then the first woodpecker that came along would destroy civilization.

[sdd]

Re: Conditional except: blocks

Robert Brewer wrote:[color=blue]
> try:
> return nextHandler(arg s)
> except (None, Exception)[self.trapErrors], exc:
> if page == u'-Error':
> raise exc[/color]
raise # re-raises the same error with the full traceback.[color=blue]
> else:
> return self.handle_err or(exc, scriptWithPath)[/color]