On Sunday 26 June 2016 02:51 PM, Joseph L. Casale wrote:
> I have some code where sys.argv is sliced up and manually fed to discrete
> argparse
> instances each with a single subparser. The reason the discrete parsers all
> having a
> single subparser was to make handling the input simpler, the first arg in the
> slice
> could be left in.
>
> This has become unmaintainable as the manual slicing is always subject to a
> new case
> by where a parser has a positional, switch or optional parameter for example.
> Also, since
> argv is grouped by subparser specifiers, if a parameter has input that
> matches a keyword
> it all goes pear shaped.
>
> The underlying root of this mess is a long unaddressed limitation in argparse
> to support
> multiple subparser specifications on the same invocation:
>
> prog.py -x -y 42 -foo bar subParserA -a 1 -b 2 subParserB -a 1 -b 2
> subParserB -a 1 -b 2
>
> The base arguments (-x -y 42 -foo bar).
> An invocation of "subParserA" and its arguments (-a 1 -b 2).
> Two invocations of "subParserB" and their arguments.
>
> etc...
>
> I have seen some creative ways to overcome this on stacktrace, however I
> thought I'd
> see what people here have done. The code is pinned at 2.7 and while several
> people
> have created alternate implementations which address many of argparses
> failures, its
> desired to stick to base lib but that can easily be changed given a
> compelling reason
> if an alternate implementation exists that works well.
Not sure if this fits the bill, or makes sense here, but I came cross
"docopt" which touts itself as a "Command-line interface description
language". I used it in a project and it seems to be pretty easy to use
as well as elegant. It stores the arguments & values as a dictionary,
keyed by the argument.
from docopt import docopt
arguments = docopt(__doc__, version='0.2')
# Set verbose flag
verbose = False
if arguments['--verbose']:
verbose = True
elif arguments['-q']:
verbose = False
# If --noencrypt, --nosign or --notransfer is specified, put that in config
if arguments['--no-encrypt']:
config['noencrypt'] = True
else:
config['noencrypt'] = False
if arguments['--no-sign']:
config['nosign'] = True
else:
config['nosign'] = False
if arguments['--no-transfer']:
config['notransfer'] = True
else:
config['notransfer'] = False
and so on ...
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