alter.red

alter-tests.red

b: []
;== []
v1: ["a" "B"]
;== ["a" "B"]
v2: ["A" "b"]
;== ["A" "b"]


alter b v1 b
;== [["a" "B"]]
alter b v2 b
;== []
alter/same b v1 b
;== [["a" "B"]]
alter/same b v2 b
;== [["a" "B"] ["A" "b"]]
alter/case b v2 b
;== [["a" "B"]]
alter b v2 b
;== []

alter.red

;Added /case and /same refinements to alter function
;https://gitter.im/red/red?at=5eae8a6ea9de3d01b1e5a34c
;https://github.com/red/red/issues/3190
alter: func [
	"If a value is not found in a series, append it; otherwise, remove it. Returns true if added"
	series [series!]
	value
	/case "Case-sensitive comparison"
	/same {Use "same?" as comparator}
	/local find'
][
	find': copy either same ['find/same][
		either case ['find/case] [to path! 'find]
	]
	if series? :value [append find' 'only]
	not none? unless remove do compose [(find') series :value] [
		either series? :value [append/only series :value] [append series :value]
	]
]