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Title: argparse should allow displaying argument default values in addition to setting a formatter class
Type: enhancement Stage: test needed
Components: Library (Lib) Versions: Python 3.5
Status: open Resolution:
Dependencies: Superseder:
Assigned To: Nosy List: bethard, denilsonsa, paul.j3, zbysz
Priority: normal Keywords:

Created on 2011-09-20 22:28 by denilsonsa, last changed 2022-04-11 14:57 by admin.

Messages (4)
msg144354 - (view) Author: Denilson Figueiredo de Sá (denilsonsa) Date: 2011-09-20 22:28
In my script, I wanted two things at the same time:
1. Setting a formatter class so that the epilog would have the line breaks preserved.
2. Telling argparse to automatically display default values for all arguments.

Currently, both things are handled by the same configuration parameter: formatter_class
This means we can either pass argparse.RawDescriptionHelpFormatter or argparse.ArgumentDefaultsHelpFormatter, but not both.

I did a hackish workaround by subclassing both formatters, and passing my (empty) subclass to ArgumentParser. It works for now, but it might break on future versions.

The ideal solution, however, would have a native support for both features, or at least explicitly allowing subclassing.
Maybe ArgumentDefaultsHelpFormatter could be transformed into a simple boolean parameter passed to ArgumentParser object (and maybe also passed to add_argument() method), instead of being a formatter class.
msg144475 - (view) Author: Zbyszek Jędrzejewski-Szmek (zbysz) * Date: 2011-09-23 21:04
Yeah, adding a formatter instance seems overkill for the usual case of wanting to preserver formatting of the epilog.
msg144500 - (view) Author: Denilson Figueiredo de Sá (denilsonsa) Date: 2011-09-24 15:54
> adding a formatter instance seems overkill for the usual case of
> wanting to preserve formatting of the epilog.

Related bug (look at it before (re)designing the API):
msg149537 - (view) Author: Steven Bethard (bethard) * (Python committer) Date: 2011-12-15 12:05
Your solution is actually the current recommended solution - mix together both classes that you want to combine and pass your subclass as the parameter. This should probably be documented somewhere (and tested more).
Date User Action Args
2022-04-11 14:57:21adminsetgithub: 57232
2014-07-16 13:09:35BreamoreBoysetnosy: + paul.j3

versions: + Python 3.5, - Python 3.3
2011-12-15 12:05:44bethardsetmessages: + msg149537
2011-09-24 15:54:52denilsonsasetmessages: + msg144500
2011-09-23 21:04:26zbyszsetnosy: + zbysz
messages: + msg144475
2011-09-23 19:39:25terry.reedysetnosy: + bethard
stage: test needed

versions: - Python 2.7, Python 3.2, Python 3.4
2011-09-20 22:28:26denilsonsacreate