There is one flaw in the command completion. Take for example the following command line:
Here the name of the input file is also -infile. When the user tries completing the next option the suggestions will not suggest the usual options (as they should), but suggest files names because the code thinks that that last -infile is a function argument. I cannot think of a solution, and in practice I don't expect anyone to actually have such file names, so I'll just leave it like this for now.