docopt is <i>almost</i> perfect.  It needs to support optional flag arguments (á la `--color[=WHEN]), and having the first un-indented line after `Usage:` be treated as prose.  The latter is on `master` of the Python (reference) implementation, but hasn&#x27;t landed in a release or a spec.<p>Also, better errors for when the programmer screws up the formatting of the doc string.