Round-robin cycling through a series

cycler.red

Red []

cycler: context [
	_data: none
	_key:  none
	set-data: func [data [block!]][
	    _data: copy data
	    ; Should we make sure the data conforms to our needs?
		;if (last data) <> (first data) [
			append/only _data first _data
		;]
		_key: last data
		
	]
	take: does [_key: select/only _data _key]
	test: does [loop length? _data [probe take]]
]

cyc: make cycler []
cyc/set-data [0 1 2 3 4 5 6 7 8 9]
cyc/test

cyc: make cycler []
cyc/set-data [a #test 5x5 8 "key" %file 10%]
cyc/test

cyc: make cycler []
cyc/set-data [[a #test] [5x5 8] ["key" %file 10%]]
cyc/test