[Python-Dev] PEP 389: argparse - new command line parsing module

Sat Oct 3 18:38:31 CEST 2009

On Sat, Oct 3, 2009 at 7:21 PM, Michael Foord <fuzzyman at voidspace.org.uk> wrote:
> [snip...]
> Why not just catch SystemExit? If you want a custom exception the overriding .exit() should be sufficient.
> I'd be much more interested in Guido's suggestion of auto-generated custom help messages for sub-commands.

Check it out:
def ParseAndRun():
 crazy_external_function_that_might_exit()
 # Argparse blah blah
 parser.parse_args()
if __name__ == "__main__":
 try:
 ParseAndRun()
 except SystemExit:
 # was it crazy_external_function_that_might_exit or an argparse error?
I know this might come through as bike shedding but it's just
customary python that every module have it's own exception types as to
not mix them up with others.
--yuv