Argument parsing is a mess.

I was inspecting your code to fix the "unreachable code" warning.  
But honestly, you should just rewrite this part with [std/parseopt](https://nim-lang.org/docs/parseopt.html)

asOptionalParam() used once on a code that ALWAYS quits, so this part of template is completely useless:
```nim
        if paramVar.isNone:
          i += 1
        else:
          i += 2
```