Python options and ROOT options

ROOT
3

Hello Duc and Wim,

from Wims last post it is obvious, that one can prevent ROOT from intercepting the command line arguments, by hiding them during importing, like so:

import sys
tmpargv = sys.argv
sys.argv = [ '-b','-n' ]
#sys.argv=[] #also works, of course
import ROOT
sys.argv = tmpargv
from optparse import OptionParser

Then the Optionparser works as expected, and shows its help.

If one wants to have the -b and -n options in a PyROOT script, this can be achieved with a simple callback function for the OptionParser and importing ROOT after dealing with the other command line options. Like in this example script:

#!/usr/bin/env python
import sys
from optparse import OptionParser

grootargs = []
def callback_rootargs(option, opt, value, parser):
    grootargs.append(opt)

parser = OptionParser('drawemptycanvas.py [-b] [-n]')
parser.add_option("-b",action="callback",callback=callback_rootargs,
                  help="run in batch mode wihtout graphics.")
parser.add_option("-n",action="callback",callback=callback_rootargs,
                  help="do not execute logon and logoff macros as"
                  "specified in .rootrc")

(options, args) = parser.parse_args()

sys.argv = grootargs
from ROOT import TCanvas

TCanvas()

Indeed this is not pretty, but works very good.

Cheers
Matthias