While I really like the argparse module, I've run into a case I think it ought to handle that it doesn't. So I'm asking here to see if 1) I've overlooked something, and it can do this, or 2) there's a good reason for it not to do this or maybe 3) this is a bad idea. The usage I ran into looks like this: parser.add_argument('configfile', default='/my/default/config', type=FileType('r'), nargs='?') If I provide the argument, everything works fine, and it opens the named file for me. If I don't, parser.configfile is set to the string, which doesn't work very well when I try to use it's read method. Unfortunately, setting default to open('/my/default/config') has the side affect of opening the file. Or raising an exception if the file doesn't exist (which is a common reason for wanting to provide an alternative!) Could default handling could be made smarter, and if 1) type is set and 2) the value of default is a string, call pass the value of default to type? Or maybe a flag to make that happen, or even a default_factory argument (incompatible with default) that would accept something like default_factory=lambda: open('/my/default/config')? Thanks, <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/ Independent Software developer/SCM consultant, email for more information. O< ascii ribbon campaign - stop html mail - www.asciiribbon.org