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Re: Why is the argparse module so inflexible?

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Date Thu, 27 Jun 2013 12:02:22 -0400
From Dave Angel <davea@davea.name>
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On 06/27/2013 09:49 AM, Andrew Berg wrote:
> On 2013.06.27 08:08, Roy Smith wrote:
>> Can you give us a concrete example of what you're trying to do?
> The actual code I've written so far isn't easily condensed into a short simple snippet.
> I'm trying to use argparse to handle all the little details of parsing and verifying arguments in the precmd hook for a cmd.Cmd child class.
> argparse's help system is more sophisticated than cmd's help and does all the work of verifying arguments.
> The problem I keep running into is that I can't handle any bad input very well. I would have to override every method that catches
> ArgumentError in order to get a useful exception that I would then handle.
> If I input something that begins with '-' that isn't recognized, parse_args doesn't even raise the exception; it just quits.

No, it raises the SystemExit exception.  if you don't catch it, then the 
program exits.  Perhaps it's not clear to you, but sys.exit() just 
raises the SystemExit exception, as  Joshua pointed out.

> In this case,
> the message gets mangled if error is overridden, and I don't know why.
>

I can't help there.


-- 
DaveA

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Thread

Why is the argparse module so inflexible? Andrew Berg <robotsondrugs@gmail.com> - 2013-06-27 07:54 -0500
  Re: Why is the argparse module so inflexible? Roy Smith <roy@panix.com> - 2013-06-27 09:08 -0400
    Re: Why is the argparse module so inflexible? Andrew Berg <robotsondrugs@gmail.com> - 2013-06-27 08:49 -0500
    Re: Why is the argparse module so inflexible? Dave Angel <davea@davea.name> - 2013-06-27 12:02 -0400
      Re: Why is the argparse module so inflexible? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-27 22:49 +0000
        Re: Why is the argparse module so inflexible? Cameron Simpson <cs@zip.com.au> - 2013-06-28 09:34 +1000
        Re: Why is the argparse module so inflexible? Ethan Furman <ethan@stoneleaf.us> - 2013-06-28 18:36 -0700
          Re: Why is the argparse module so inflexible? rusi <rustompmody@gmail.com> - 2013-06-28 21:12 -0700
            Re: Why is the argparse module so inflexible? Terry Reedy <tjreedy@udel.edu> - 2013-06-29 00:37 -0400
              Re: Why is the argparse module so inflexible? Roy Smith <roy@panix.com> - 2013-06-29 10:12 -0400
                Re: Why is the argparse module so inflexible? Andrew Berg <robotsondrugs@gmail.com> - 2013-06-29 09:17 -0500
          Re: Why is the argparse module so inflexible? Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-06-29 05:28 +0000
            Re: Why is the argparse module so inflexible? Marcin Szamotulski <mszamot@gmail.com> - 2013-06-29 13:38 +0100
            Re: Why is the argparse module so inflexible? MRAB <python@mrabarnett.plus.com> - 2013-06-29 16:58 +0100
            Re: Why is the argparse module so inflexible? Ethan Furman <ethan@stoneleaf.us> - 2013-06-29 12:17 -0700
        Re: Why is the argparse module so inflexible? Modulok <modulok@gmail.com> - 2013-06-28 19:39 -0600
        Re: Why is the argparse module so inflexible? Isaac To <isaac.to@gmail.com> - 2013-06-29 12:37 +0800
    Re: Why is the argparse module so inflexible? Robert Kern <robert.kern@gmail.com> - 2013-06-27 20:47 +0100

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