Optparse and help formatting?

[Steven Bethard]

Tim Chase wrote:
> I've been learning the ropes of the optparse module and have been
> having some trouble getting the help to format the way I want.
> 
> I want to specify parts of an option's help as multiline.
> However, the optparse formatter seems to eat newlines despite my
> inability to find anything in optparse.py that does something
> obvious like .replace("\n", " ") to eat the newlines I stick in
> the help.  It also seems to mung tabs.  An example from my code:
> 
> parser.add_option("-x", "--extended",
>   action="callback",
>   callback=callback_test,
>   type="string",  # required to get metavar to show in help
>   dest="test",
>   metavar="CONF",
>   help="a comma-separated list of options.\n"
>     "s=[YYYY]MMDD,n=NAME,c=COLOR\n"
>     "s,start=[YYYY]MMDD\n"
>     "\tstart day of period (default, current day)\n"
>   ...
>   )
> 
> which would accept options that looked something like
> 
>   test.py -x s=20070401,n=XR71,c=black
> 
> (my callback_test breaks apart parser.rargs[0] to deal with the
> funky params).
> 
> However, when I display the help, its reformatting eats the
> newlines in my help-string and strangely looks like it converts
> my tabs to spaces.
> 
> Any hints on how to either work around the problem or fix it?

I guess this is just an optparse-y week on c.l.py. ;-)  Ben Finney 
pointed you in the right direction for optparse.

If you care to try out argparse (http://argparse.python-hosting.com/) 
which has a similar API, it has a builtin RawTextHelpFormatter formatter 
class::

     import argparse

     def my_type(string):
         # split string and turn it into appropriate object(s)
         return 'foo(%s)' % string

     parser = argparse.ArgumentParser(
         formatter_class=argparse.RawTextHelpFormatter
     )
     parser.add_argument(
         "-x", "--extended",
         type=my_type,  dest="test", metavar="CONF",
         help="a comma-separated list of options.\n"
              "s=[YYYY]MMDD,n=NAME,c=COLOR\n"
              "s,start=[YYYY]MMDD\n"
              "\tstart day of period (default, current day)\n"
     )

     args = parser.parse_args()
     print args.test

This program will produce output like::

     $ python script.py -x sdfsdfas
     foo(sdfsdfas)

     $ python script.py --help
     usage: script.py [-h] [-x CONF]

     optional arguments:
       -h, --help            show this help message and exit
       -x CONF, --extended CONF
                             a comma-separated list of options.
                             s=[YYYY]MMDD,n=NAME,c=COLOR
                             s,start=[YYYY]MMDD
                                     start day of period ...

HTH,

STeVe