resume execution after catching with an excepthook?

[Prasad, Ramit]

andrea crotti wrote:
> 2012/10/25 Steven D'Aprano <steve+comp.lang.python at pearwood.info>:
> > On Wed, 24 Oct 2012 13:51:30 +0100, andrea crotti wrote:
> >
[snip]
> > Without a try...except block, execution will cease after an exception is
> > caught, even when using sys.excepthook. I don't believe that there is any
> > way to jump back to the line of code that just failed (and why would you,
> > it will just fail again) or the next line (which will likely fail because
> > the previous line failed).
> >
> > I think the only way you can do this is to write your own execution loop:
> >
> > while True:
> >     try:
> >         run(next_command())
> >     except KeyboardInterrupt:
> >         if confirm_quit():
> >             break
> >
> >
> > Of course you need to make run() atomic, or use transactions that can be
> > reverted or backed out of. How plausible this is depends on what you are
> > trying to do -- Python's Ctrl-C is not really designed to be ignored.
> >
> > Perhaps a better approach would be to treat Ctrl-C as an unconditional
> > exit, and periodically poll the keyboard for another key press to use as
> > a conditional exit. Here's a snippet of platform-specific code to get a
> > key press:
> >
> > http://code.activestate.com/recipes/577977
> >
> > Note however that it blocks if there is no key press waiting.
> >
> > I suspect that you may need a proper event loop, as provided by GUI
> > frameworks, or curses.
> >
> 
> Ok thanks, but here the point is not to resume something that is going
> to fail again, just to avoid accidental kill of processes that take a
> long time.  Probably needed only by me in debugging mode, but anyway I
> can do the simple try/except then, thanks..

On the other hand, if you store state externally (pickle?) maybe 
you can just restart at the last "check point". That way even if
the program dies you can recover on the next run.

Ramit Prasad


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