argparse limitations

[Benoist Laurent]

Hi,

I'm impletting a tool in Python.
I'd like this tool to behave like a standard unix tool, as grep for exemple.
I chose to use the argparse module to parse the command line and I think I'm getting into several limitations of this module.

> First Question.
How can I configure the the ArgumentParser to allow the user to give either an input file or to pipe the output from another program?

$ mytool.py file.txt
$ cat file.txt | mytool.py


> Second Question.
How can I get the nargs options working with subparser?
Cause basically if I've got a positionnal argument with nargs > 1, then the subparsers are recognized as values for the positionnal argument.

$ mytool.py file1.txt file2.txt foo

Here foo is a command I'd like to pass to mytool but argparse considers it's another input file (as are file1.txt and file2.txt).


Any help would be appreciated.
Ben.