Allow users to specify name of module

[lydia-duncan]

At the moment, compiling a Chapel module into a Python module will always generate an a_out.py file which the user must move to a different filename if they don't like the name a_out.py. It would be nice to be able generate a user-defined name from the pych command, so that this step can be skipped.

First idea, should it look like this? What would be better syntax?

pych --compile blah.chpl -o blah.py

[thomasvandoren]

What if the default name was the same as the chapel file replacing .chpl with .py? It probably should do some name massaging to ensure the python module name is valid and importable (e.g. substitute _ for .). For example:

pych --compile blah.chpl        # --> blah.py
pych --compile MyCoolCode.chpl  # --> MyCoolCode.py
pych --compile a.out.chpl       # --> a_out.py

[thomasvandoren]

I also like the -o some_other_name.py option. It allows the python module name to be anything.

[lydia-duncan]

I definitely like that general default behavior better, though I would hesitate to replace periods with underscores by default.