[Python-Dev] PEP 389: argparse - new command line parsing module (original) (raw)

Paul Moore p.f.moore at gmail.com
Tue Sep 29 22:31:58 CEST 2009

2009/9/28 Yuvgoog Greenle <ubershmekel at gmail.com>:

1. There is no chance of the script killing itself. In argparse and optparse exit() is called on every parsing error (btw because of this it sucks to debug parseargs in an interpreter).

That one does worry me. I'd rather argparse (or any library function) didn't call sys.exit on my behalf - it should raise an exception. Is it actually true that argparse exits? (I can imagine that it might if --help was specified, for example. An exception may not be right here, but I still don't like the idea of a straight exit - I've used too many C libraries that think they know when I want to exit).

2. There is no chance the parser will print things I don't want it to print.

That may also be bad - for example, Windows GUI-mode programs raise an error if they write to stdout/stderr. I could imagine using argparse for such a program, and wanting to do something with --help other than write to stdout and exit (a message box, for example). And yet, I'd want access to the text argparse would otherwise write to stdout.

Paul.

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