Behaviour of the docopt module (argument parser)

Question

I currently use the docopt lib for the first time so I surely do something wrong

My script is :

"""prog

Usage:
    prog.py (-h | --help)
    prog.py (--version)
    prog.py -s TAG [-t NB_NUC]

Options:
    -h, --help   help
    --version    version
    -s TAG       Some TAG I want.
    -t NB_NUC    A number of nuc.
"""

If I write: python prog.py -s SMT

I get:

{'--help': False,
    '--version': False,
    '-h': False,
    '-s': True,
    '-t': True,
    'NB_NUC': None,
    'TAG': 'SMT'}

And it seems to be correct, but if I write :

python prog.py -s -t 10 -> TAG contain 10 (instead of None)
python prog.py -t 10 -s SMT -> TAG contain always 10 (instead of SMT) and NB_NUC contain SMT (instead of 10)
python prog.py -s SMT -t -> TAG contain SMT and NB_NUC contain None (and its what I expected on this way)

So, I tried lot a combination, but I don't understand how this is supposed to word...

What I want is TAG always contains the values which correspond with the -s argument, with None or an error if nothing is given after -s, and I don't understand why it's not the case..

Thanks for your help !

score 0 · Answer 1 · answered Mar 09 '16 at 15:23

0

Your are almost there, just need the "<...>" around the arguments:

"""prog

Usage:
    prog.py (-h | --help)
    prog.py (--version)
    prog.py -s TAG [-t NB_NUC]

Options:
    -h, --help   help
    --version    version
    -s TAG       Some TAG I want.
    -t NB_NUC    A number of nuc.
"""

answered Mar 09 '16 at 15:23

J. P. Petersen

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Hi, thanks for your help.I found the problem: it because the lines in my help are tabulation indented, and not space indented, and by replacing tabulation with spaces it's work fine now.. I have post an issue about that on the docopt github. – Liad Mar 11 '16 at 12:50

score 0 · Accepted Answer · answered Mar 11 '20 at 12:24

The problem came from the fact that previous version of docopt didn't work with tabulated indentation. Actual version does, and the PEP8 recommend usage of spaces anyway.

And for the formating the easiest way is to only write

Usage:
    prog.py (-h | --help)
    prog.py (-v | --version)
    prog.py [options] <mandatory_file>

And to put the differents options and their descriptions in the Options part.

Behaviour of the docopt module (argument parser)

2 Answers2