STDIN/STDOUT reference `-` can't be used as argument

[alerque]

In most *nix tooling, - can be used as an alias for either /dev/stdin or /dev/stdout (depending on what is expected in the context). I can't figure out how to pars thet using this library. It looks like it is parsable as an argument after a -- separator, but in all other circumstances (where it might be expected)

Sample expected usage:

$ my_cmd -f -