option argument length

[Peter Otten]

Ritesh Raj Sarraf wrote:

> I'm using this for "option arguments" which are mutually inclusive.
> But I want the user to pass atleast one "option argument" for the program
> to function properly.
> 
> For example, I have an option "--fetch-update" which requires a file "foo"
> to check what it has to fetch. If the file is provided as an argument, it
> uses it, else I add a parser.set_defaults("foo") which makes the program
> to look for it in the current working directory.
> 
> WHen the program see the "--fetch-update" option, it should execute the
> required code. Now how do I check if at least one option has been passed
> at the command-line ?
> I have multiple options but I have parser.set_defaults() for each of them.

I'm sorry I don't understand your example. Wouldn't you need at least two
options to demonstrate "mutually inclusive" options? The set_default()
method seems to accept only keyword arguments -- but even it were used
correctly I'm still unclear why you would need it at all. 

Perhaps you can post a few sample invocations (both correct and illegal) of
your script together with a description (in English, not code) of how the
script should react?

Peter, puzzled