Re: shell completion support for optparse/optik

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i think more and more that the idea could work, it's too easy, here is a 
tentative little hack i just fiddled:

1. in a bash shell, enter the following:

   complete -C '/tmp/completion-test --optparse-complete ' completion-test

this will invoke the program itself when completion is asked on it.

2. copy the simple test program in attachment in /tmp/completion-test

3. type /tmp/completion-test<TAB>


now there only remains to have a look at the current point and the line, and 
to print on stdout the completions, one per line, using information from the 
given OptionParser.

issues:

- - how do we setup the completion instructions above without having to list 
each individual program that we want to be able to complete this way?  if at 
least a simple list of them can be enumerated, i guess i could create a shell 
function to do this and then invoke it for every program, e.g.

install_optparse_completion(completion-test)
install_optparse_completion(other-program)
...


- - in my example, it means that a user cannot add --optparse-complete to his 
own set of options;  what name to assign, any ideas on another way to do 
this?


- - should individual options have possibility for individual completion 
methods? e.g.  parser.add_option(... complete=<method>)

i think so, this would mean that

program --option=<TAB>

could complete with the "--option"'s specific requirements, how cool is that?


- - i'd like to find a good set of default completion methods to add to the 
library, so that adding completion in the most common cases doesn't require 
you to declare a class;

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#!/usr/bin/env python

# This functionality should be implemented within the parse_args()
# function.
def parse_args_complete():

    # this should be hidden behaviour within the optparse module
    import sys
    if len(sys.argv) > 1 and sys.argv[1] == '--optparse-complete':

        # FIXME todo: compute possible completions, using parser object
        # note that you're getting the following variables as input
        # in the environment:
        # COMP_CWORD
        # COMP_LINE
        # COMP_POINT
        # COMP_WORDS
	# import os
	# print >> sys.stderr, os.environ['COMP_LINE']

        print 'completion1'
        print 'completion2'
        print 'completion3'
        sys.exit(1)

    else:
        return parser.parse_args()


import os, optparse
parser = optparse.OptionParser()
parser.add_option('--bla', help="Bla optino.")
# ...

# Note: this should be calling the normal parse_args() method.
opts, args = parse_args_complete()

# ...
print 'Executing command'
print 'opts', opts
print 'args', args