Control formatting of the argparse help argument list?

Question

import argparse
parser = argparse.ArgumentParser(prog=\'tool\')
args = [(\'-u\', \'--upf\', \'ref. upf\', dict(required=\'True\')),
        (\'-s\', \'--skew\', \'ref. s         


        

Answer 1

Inspired by @jfs's answer, I have come up with this solution:

def make_wide(formatter, w=120, h=36):
    """Return a wider HelpFormatter, if possible."""
    try:
        # https://stackoverflow.com/a/5464440
        # beware: "Only the name of this class is considered a public API."
        kwargs = {'width': w, 'max_help_position': h}
        formatter(None, **kwargs)
        return lambda prog: formatter(prog, **kwargs)
    except TypeError:
        warnings.warn("argparse help formatter failed, falling back.")
        return formatter

Having that, you can call it with any HelpFormatter that you like:

parser = argparse.ArgumentParser(
    formatter_class=make_wide(argparse.ArgumentDefaultsHelpFormatter)
)

or

parser = argparse.ArgumentParser(
    formatter_class=make_wide(argparse.HelpFormatter, w=140, h=20)
)

What this does is make sure that the wider formatter can actually be created using the width and max_help_position arguments. If the private API changes, that is noted by make_wide by a TypeError and the formatter is returned unchanged. That should make the code more reliable for deployed applications.

I'd welcome any suggestions to make this more pythonic.