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Re: Why is the argparse module so inflexible?

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Date Thu, 27 Jun 2013 08:49:23 -0500
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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. In this case,
the message gets mangled if error is overridden, and I don't know why.

> You might look into "type=".  It's normally used for things like 
> "type=int" or "type=float", but it could give it any user-defined 
> function as a type and this essentially becomes a hook to insert your 
> own code into the middle of the processing.  Sometimes that can be 
> warped into doing all sorts of useful things.
I don't think that would solve my problem, but it would probably be quite useful.
-- 
CPython 3.3.2 | Windows NT 6.2.9200 / FreeBSD 9.1

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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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