02-07-2010, 03:55 PM
It seems to be the characters used in the commands(-- and ?). I guess "is" doesn't evaluate those. Here is an example using and interactive session with python.
I guess it's just safer to use "==".
Code:
>>> p = 'h'
>>> if p is 'h':
print 'hi'
hi
>>> p = 'h?'
>>> if p is 'h?':
print 'hi'
>>> p = '--h'
>>> if p is '--h':
print 'hi'
>>> if p == '--h':
print 'hi'
hi
>>>