Unclear error with multiline description

[agilly]

Using multiline descriptions at initialisation, like:

parser <- ArgumentParser(description="Description of tool.\nAuthor information.")
parser$parse_args()

produces an error:

Error in if (grepl("^\\{|^\\[", output)) { : the condition has length > 1
Calls: <Anonymous> -> parse_args_output
Execution halted

I am not sure you want to support multiline descriptions (it kind of makes sense to IMO?) but in any case the error message should probably be made clearer.

R 4.2.1, python version 3.6.9

[trevorld]

Looking at the behavior of python's argparse module it doesn't support multiline descriptions. However it will quietly convert any newlines into spaces instead of throwing an error.

import argparse

parser = argparse.ArgumentParser(description="Description of tool.\n\nAuthor info")
parser.parse_args()

usage: argparse_test.py [-h]

Description of tool. Author info

optional arguments:
  -h, --help  show this help message and exit

Currently {argparse} is simply a wrapper around Python's argparse module so it wouldn't be straightforward to add multiline descriptions but it is probably feasible to quietly convert those newlines to spaces.

[agilly]

Thanks for the explanation and fix @trevorld !

[trevorld]

After f22b70c46c337 multiline descriptions should work but (like with Python) you'll need to use formatter_class='argparse.RawDescriptionHelpFormatter':

library("argparse")
parser <- ArgumentParser(description="Description of tool.\nAuthor information.", 
                                           formatter_class='argparse.RawDescriptionHelpFormatter')
parser$print_help()

usage: PROGRAM [-h]

Description of tool.
Author information.

optional arguments:
  -h, --help  show this help message and exit