argparse ConfigureAction problem

[Neal Becker]

I've been using arparse with ConfigureAction (which is shown below). But, it
doesn't play well with positional arguments. For example:

../plot_stuff2.py --plot stuff1 stuff2
[...]
plot_stuff2.py: error: argument --plot/--with-plot/--enable-plot/--no-plot/--
without-plot/--disable-plot: invalid boolean value: 'stuff1'

Problem is --plot takes an optional argument, and so the positional arg is
assumed to be the arg to --plot. Not sure how to fix this.


Here is the parser code:

parser = argparse.ArgumentParser()

[...]
parser.add_argument ('--plot', action=ConfigureAction, default=False)
parser.add_argument ('files', nargs='*')

opt = parser.parse_args(cmdline[1:])

Here is ConfigureAction:

-----------------------------------------------------
import argparse
import re


def boolean(string):
string = string.lower()
if string in ['0', 'f', 'false', 'no', 'off']:
return False
elif string in ['1', 't', 'true', 'yes', 'on']:
return True
else:
raise ValueError()


class ConfigureAction(argparse.Action):

def __init__(self,
option_strings,
dest,
default=None,
required=False,
help=None,
metavar=None,
positive_prefixes=['--', '--with-', '--enable-'],
negative_prefixes=['--no-', '--without-', '--disable-']):
strings = []
self.positive_strings = set()
self.negative_strings = set()
for string in option_strings:
assert re.match(r'--[A-z]+', string)
suffix = string[2:]
for positive_prefix in positive_prefixes:
self.positive_strings.add(positive_prefix + suffix)
strings.append(positive_prefix + suffix)
for negative_prefix in negative_prefixes:
self.negative_strings.add(negative_prefix + suffix)
strings.append(negative_prefix + suffix)
super(ConfigureAction, self).__init__(
option_strings=strings,
dest=dest,
nargs='?',
const=None,
default=default,
type=boolean,
choices=None,
required=required,
help=help,
metavar=metavar)

def __call__(self, parser, namespace, value, option_string=None):
if value is None:
value = option_string in self.positive_strings
elif option_string in self.negative_strings:
value = not value
setattr(namespace, self.dest, value)