Argument parsing, validation from manifest preamble

[homonoidian]

Like in Python docopt, runtime gets arguments as words (or in an args block for instance, as in args.filename, or args.optlevel, etc.) How the usage should be parsed out I have no idea at the moment, but it's perfectly doable of course. The syntax is yet to be clarified.

nolayout
hello.nk
---
Some help message stuff...

Usage:
   --  <filename> [optlevel]

Some more help message stuff...

And in hello.nk for instance:

'Filename: ' args.filename ~ echo
args.optlevel? => [ 'Optlevel:' _ echo ]

"It'd be nice to automatically define ( -- V true / false ) to get the Value of an optional parameter"