Thought I'd just point a much simpler and efficient implementation of GetArgs

Although efficiency isn't that important with such a small data set, it's useful to know how to do things like this better.

let rec GetArgs = function
| "–" :: rest -> List.to_array rest
| _ :: tail -> GetArgs tail
| [] -> Array.empty

It also means your case of having two "–" works correctly too; all other "–" get included as actual arguments.