docopt (http://docopt.org) is neat, but this heuristic (highlighted) seems very odd to me.
Since most options are optional(!), isn’t it easy enough to distinguish “[-i] ARG” or “[-i] [ARG]” from “[-i ARG]”?
Is there really no way to cajole docopt (for R) into handling argument-free options without forgoing self-documentation? Even “[ARG] [-i]” appears not to work… 
