You can clone with
extopenscad: --help: openFile: does not exist (No such file or directory)
I'm planning to generalize argparser so that we can use it for command line arguments to. Then we'll make a nicer command line interface :)
Why don't we just use an already existing command line argument handling library? There are no shortage of excellent options (optparse-applicative comes to mind). While I really like ImplicitCAD, I must say there is a bit more reinventing of the wheel in this codebase than is appropriate in my opinion (among other things, vector-space provides a very nice typeclass hierarchy for low-dimensional vectors)
Yes, a new approach to argument handling is needed. I'd prefer cmdargs, but if you really prefer another package, feel free to implement it. Otherwise, I'd have no problem implementing it some time in the next week or two...
cmdargs is a fine library, but I do really think that the composability, purity, and lack of Template Haskell offered by optparse-applicative make it a far better option. If you haven't looked at it yet, I'd strongly recommend it. When it comes to writing easily extensible, composable parsers cmdargs's ad-hoc approach has absolutely nothing on an Applicative parser.
Note that #90 takes care of this.