cmd = Cli.mk()
	option('output', fn c: c
		{ info: Just('sum option help')
		, short: Just('o')
		})
	help('miau miau miau')

cmd = Cli.mk()
	arg(Cli.int, fn(): Cli.def())
	option('output', Cli.int, fn()): Cli.def()
		info('this is a typeclass yo')
		short('o')
		default(420)
	short('m', Cli.bool, fn()):  # only short.
		info('asjkdlajksd')
	command('build', fn()):
		arg(Cli.str)
		option('debug', Cli.bool, fn()): Cli.def()
			help('yoo!')
			default(True)
	help('miau miau miau')

xx = cmd Cli.parse(Args.get())
# ???


cmd = Cli.mk()
	arg(Cli.int, fn(s, x): s { first-arg: x }, fn(): Cli.def())
	option('output', Cli.int, fn(s, x): s { output: x }, fn()): Cli.def()
		info('this is a typeclass yo')
		short('o')
		default(420)
	short('m', Cli.bool, fn()): Cli.def() # only short.
		info('asjkdlajksd')
		required()
	command('build', fn(s, b): s { build-options: b }, fn()): Cli.def() # basically, by default it's undefined, and to override it, specify `default`.
		arg(Cli.str, fn(s, a): s { what: a })
		option('debug', Cli.bool, fn(b, d): b { debug: d }, fn()): Cli.def()
			help('yoo!')
			default(True)
		default(BuildOptions { what: @undefined, debug: False })
	help('miau miau miau')
	default(Prog { ... })


xx = cmd Cli.parse(Args.get())

# the function constructors (like fn(s, x): s { first-arg: x }) are also nice cuz instead of creating structs, 
# we can also do this: fn(_, x): some-ptr set-ptr(x) and return unit

# ...


# alternative representation!
# won't require typeclasses (at least for basic operation, we can restrict or automatically make options for different types etc)
# no need to write Cli.def()
cmd = Cli.mk(
	[ arg(Cli.int, fn(s, x): s { first-arg: x }, [])
	, option('output', Cli.int, fn(s, x): s { output: x },
			[ info('this is a typeclass yo')
			, short('o')
			, default(420)
			])
	, short('m', Cli.bool, 
			[ info('asjkdlajksd')
			, required()
			])
	]


# i think I prefer the non-list one.
# maybe only for the parameters it's not that bad.