[Python-Dev] getopt helper?

Greg Ward gward@cnri.reston.va.us
Thu, 30 Sep 1999 10:15:50 -0400

On 30 September 1999, Guido van Rossum said:
> Marc-Andre, you're not hearing what Mark is saying.  He wants a change
> to the standard library, and he knows that small additions to existing
> modules there stand a better chance of adoption than new modules.
> I personally liked the idea of getoptex() best, except I would call it 
> getopt_or_die().

Gasp!  Guido hath drunk from the poisoned well of the Great Camel and it 
doth infest his thinking!  "or die" indeed -- not an idiom I've seen
since the last time I wrote some Perl code (umm, last week?).

> If the usage message is omitted it can synthesize
> one from the (short and long) options arguments and sys.argv[0] (the
> latter being a bit controversial, but it's just a default).
> Hmm...  Perhaps getopt_or_die() shouldn't take the args argument but
> extract sys.argv[1:] itself?

Whatever we call it, it should be able to take an explicit argument
list, and only default to sys.argv[1:].  What if I want to parse options
from an environment variable or a config file?  I also like the "don't
clobber sys.argv, but return the modified version instead" model -- it's 
nice to keep a pristine copy of the original argument list!

Another problem with getopt is that it doesn't correlate long and short
options.  I wrote distutils.fancy_getopt (download your copy today!
hurry, don't delay -- at this price, it WON'T LAST LONG!) to address
this, and to maybe someday do something with help text.

On the other hand, don't listen to me -- I tend to write mammoth,
bloated, all-singing, all-dancing command-line parsing modules for every 
new language I encounter.  They get more insane with each iteration.  I
have yet to top my Getopt::Tabular for Perl, though; see


if you've ever wondered how far this sort of thing can be taken in a
high-level, dynamically typed language.

Greg Ward - software developer                    gward@cnri.reston.va.us
Corporation for National Research Initiatives    
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