Why is the argparse module so inflexible?

Andrew Berg robotsondrugs at gmail.com
Thu Jun 27 08:54:12 EDT 2013


I've begun writing a program with an interactive prompt, and it needs to parse input from the user. I thought the argparse module would be
great for this, but unfortunately it insists on calling sys.exit() at any sign of trouble instead of letting its ArgumentError exception
propagate so that I can handle it. Overriding ArgumentParser.error doesn't really help since methods like parse_known_args just send a
message to be relayed to the user as an argument after swallowing ArgumentError (which does have useful information in its attributes). If I
wanted to figure out what actually caused the exception to be raised, I'd have to parse the message, which is ugly at best. I understand
that most people do want argparse to just display a message and terminate if the arguments supplied aren't useful, but there's a lot of
potential in the module that is crippled outside the main use case. I have to wonder why a module that is meant to be imported would ever
call sys.exit(), even if that is what the caller would normally do if presented with an exception.
-- 
CPython 3.3.2 | Windows NT 6.2.9200 / FreeBSD 9.1



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