Sometimes Python programs have unhandled exceptions. Usually these make your program exit, but wouldn't it be nice if you could fix your environment in a Python shell and try again? I thought so, so I've written a very silly exception hook which gives you the option to retry the current line, or skip past it and continue executing from the next one.
It's implemented using a bytecode-patcher. Anyway, for an example, given this broken program:
def do_something(foo):
z = 1 + 2 +3
print '1 + 2 + 3 = %d' % z
return foo + bar
x = do_something(17)
print x
After the NameError is raised when we try to access bar, we see this
prompt:
$ python fail.py
1 + 2 + 3 = 6
[reckless] intercepting an exception:
Traceback (most recent call last):
File "fail.py", line 8, in <module>
x = do_something(17)
File "fail.py", line 6, in do_something
return foo + bar
NameError: global name 'bar' is not defined
c : continue execution (insane)
d : debugger (bpdb)
e : exit
[n]: do nothing
r : retry (insane)
s : shell (bpython)
what now?
We can enter s and fix the environment by defining bar:
>>> bar = 9
^D to exit the shell, and then enter r at the prompt:
[reckless] resuming execution
26
[reckless] reached end of program
$
It's on PyPI. If you're interested in
the gory details of the bytecode patching, I suggest you download it and have
a look at execute.py (it's not pretty).