[Python-Dev] getopt helper?

Barry A. Warsaw bwarsaw@cnri.reston.va.us (Barry A. Warsaw)
Thu, 30 Sep 1999 16:29:55 -0400 (EDT)

I can sympathize with Mark, I have nearly the same code in every
script I write.  I once wrote a nice (IMO) class for doing all the
common things I do with c.l. args, but I can't seem to dig it up at
the moment.

The idea was basically to have a base class that had all the
machinery, while derived classes included specially named methods that 
did the app-specific option handling.  It knew whether the method took 
1 or zero arguments (not including self), glommed up the shortarg
string and longarg list (with appropriate `:' and `=' thrown in), then 
parsed the args, dispatching to the handlers, e.g.:

    class MyOptions(getopt.Options):
	def handle_a(self):
	    self.alpha = 1
	handle_alpha = handle_a

	def handle_b(self, arg):
	    self.beta = arg
	handle_beta = handle_b

	def handle_i(self, arg):
		self.integer = int(arg)
	    except ValueError:
	handle_integer = handle_i

and could be used like so:

    #! /usr/bin/env python
    # ...

    opts = MyOptions(sys.argv[1:], usage=__doc__ % globals())
    if opts.alpha:
    if opts.integer = 1:
    for file in opts.leftoverargs:

While I liked this a lot, I seem to remember showing it to Guido,
receiving the expected scoffing.  So now, I just cut and paste the opt
parsing stuff into every script I write :) I think it might be nice to
add such a base class to the standard getopt module.