Re: partial option parsing

Hello,

Sorry it took so long to answer, other things kept stopping me.

=BB On Fri, Dec 09, 2005 at 09:19PM -0500, David Goodger wrote:

> [Francisco Borges]
> > CASE 1:
> >
> > Turning "on" certain groups of options though some action swicht:
> >
> > $ wiel train --train-specific-option
>
> Look in the list archives for "partial option parsing" (there are 2
> threads).  These directly apply to this issue.

Thank you for the pointers!! But as I haven't found any code there, here
is my own ;-)

I've subclassed OptionGroup and OptionParser to allow the use of partial
"switched" options.

The idea is:

- If group has 'switch', options are not added to the parser but stored

- If there are groups with switches and switch is in cmdline:
- add options from target group,
- continue parsing.

- only one switch can be made active, a second is considered a normal
argument.

Known Bugs: Lacking decent help messages.

   -----------

Any comments on the code?

Cheers,
Francisco.

#-----------------------------------------------------------------------
#! /usr/bin/env python
# -*- coding:iso-8859-15 -*-
#    Time-stamp: <switch.py 19dec05 19hrs 44min borges>
# $Id: switch.py 975 2005-12-19 18:50:34Z borges $
#-----------------------------------------------------------------------
"""
Group Switches for Optik.
"""
__author__ =3D 'Francisco D. Borges <[email protected]>'
__date__ =3D "$Date: 2005-12-19 19:50:34 +0100 (ma, 19 dec 2005) $"
__revision__ =3D "$Revision: 975 $"

import logging
logging.basicConfig(format=3D'%(levelname)-8s %(message)s')
log =3D logging.getLogger()
log.setLevel(5)

import optparse

class SW_OptionGroup(optparse.OptionGroup):

    def __init__(self, parser, title, description=3DNone, switch=3DNone):
        self.switch =3D switch
        self._stored_options =3D []
        optparse.OptionGroup.__init__(self, parser, title, description)

    def add_option(self, *args, **kwargs):
        if not self.switch:
            return optparse.OptionGroup.add_option(self, *args, **kwargs)
        self._stored_options.append([args, kwargs])

    def activate_opts(self):
        log.debug("activating options of '%s'" % self.switch)
        for iargs, ikwargs in self._stored_options:
            optparse.OptionGroup.add_option(self, *iargs, **ikwargs)

OptionGroup =3D SW_OptionGroup

class SW_OptionParser(optparse.OptionParser):

    def parse_args(self, args=3DNone, values=3DNone):
        switches =3D [ g.switch for g in self.option_groups if g.switch ]
        if not switches:
            log.debug("No switches!")
            return optparse.OptionParser.parse_args(self, args, values)
        elif len(switches) !=3D len(set(switches)):
            log.error(" ".join(switches))
            raise StandardError
        return self.parse_switch(args, values, switches)

    def parse_switch(self, args, values, switches):
        """Parse command line activating switched options if switch is fo=
und.

Some observations:
- all groups with switches are OFF untill switch is seen;
- there can be only one switch per command line.
- if interspersed_args was disable, things might not work (for you :-P).
"""
        if self.allow_interspersed_args:
            old_interspersed =3D True
            self.disable_interspersed_args()
        else:
            old_interspersed =3D False

        opt, new_values =3D optparse.OptionParser.parse_args(self, args, =
values)

        if not new_values:
            return opt, new_values

        if new_values[0] not in switches:
            log.debug("No valid switches found!")
            if not old_interspersed: # XXX A horrible "if 'not True'"
                return opt, new_values
        else:
            log.debug("Switch is ON")
            switch =3D new_values.pop(0)
            for group in self.option_groups:
                if group.switch =3D=3D switch:
                    group.activate_opts()
                    break

        if old_interspersed:
            self.enable_interspersed_args()

        opt2, values2 =3D optparse.OptionParser.parse_args(self, new_valu=
es, values)

        # Re-set changed values and add new options:
        for k, v in self.defaults.iteritems():
            curval =3D getattr(opt2, k, v)
            if curval !=3D v or not hasattr(opt, k):
                setattr(opt, k, curval)
        return opt, values2


if __name__ =3D=3D '__main__':
    prs =3D SW_OptionParser()
    prs0 =3D SW_OptionParser()

    # General Option...
    gopts =3D [prs0.add_option('--path', help=3D'Some path...')]

    ginp =3D OptionGroup(prs, 'Input Options', switch=3D'input')
    ginp.add_option('-m', '--model', action=3D"store", dest=3D'modelfile'=
,
                    metavar=3D'FILE', help=3D"Model to use")
    ginp.add_option('-b', '--base-line', action=3D'store_true', dest=3D'b=
aseline',
                    help=3D'Determine a baseline performance')
    ginp.add_option('--models-dir', action=3D'store', dest=3D'mdir', meta=
var=3D'DIR',
                   default=3D'.', help=3D'Directory where to find multipl=
e models.')
    ginp.add_options(gopts)

    g2 =3D OptionGroup(prs, '2G: Output', switch=3D'output')
    g2.add_option("--g2only", help=3D'Some help')
    g2.add_options(gopts)

    g3 =3D OptionGroup(prs, '3G: Always ON!')
    g3.add_option('--g3only', help=3D'more help')

    prs.add_option_group(ginp)
    prs.add_option_group(g2)
    prs.add_option_group(g3)

    (opt, args) =3D prs.parse_args()
    print opt, args



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