[SOLVED] Can Python's argparse permute argument order like gnu getopt?

Can Python's argparse permute argument order like gnu getopt?

GNU getopt, and command line tools that use it, allow options and arguments to be interleaved, known as permuting options (see http://www.gnu.org/software/libc/manual/html_node/Using-Getopt.html#Using-Getopt). Perl's Getopt::Long module also supports this (with qw(:config gnu_getopt)). argparse seems to not support (or even mention) permuting options.

There are many SO questions related to arg/opt order, but none seem answer this question: Can argparse be made to permute argument order like getopt?

The use case is a prototypical command line signature like GNU sort:

sort [opts] [files]

in which 1) options and files are permuted, and 2) the file list may contain zero or more arguments.

For example:

import argparse
p = argparse.ArgumentParser();
p.add_argument('files',nargs='*',default=['-']);
p.add_argument('-z',action='store_true')

p.parse_args(['-z','bar','foo']) # ok
p.parse_args(['bar','foo','-z']) # ok
p.parse_args(['bar','-z','foo']) # not okay
usage: ipython [-h] [-z] [files [files ...]]

I've tried:

p.parse_known_args -- doesn't complain, but doesn't actually permute either and it doesn't balk about arguments that look like invalid options (e.g., --bogus or -b above).
p.add_argument('files',nargs=argparse.REMAINDER) -- option -z is included in files unless before positional args
p.add_argument('files',nargs='*',action='append');

I want to implement something close to the GNU sort prototype above. I am not interested in a flag that can be specified for each file (e.g., -f file1 -f file2).

Solution