Example of a custom iterator in GDScript

rangeIterator.gd

class RangeIterator:
	var current
	var end
	var change
	
	func stop():
		if change > 0:
			return current >= end
		else:
			return current <= end
	
	func init_end(e):
		current = 0
		end = e
		if e > 0:
			change = 1
		else:
			change = -1
	
	func init_start_end(s, e):
		current = s
		end = e
		if e > s:
			change = 1
		else:
			change = -1
	
	func init_start_end_change(s, e, c):
		current = s
		end = e
		change = c
	
	# override bool _iter_init(?)
	func _iter_init(arg):
		return !stop()
	
	# override bool _iter_next(?)
	func _iter_next(arg):
		current += change
		return !stop()
	
	# override Variant _iter_get(?)
	func _iter_get(arg):
		return current



func example():
	var iter = RangeIterator.new()
	iter.init_start_end(5,10)
	
	for i in iter:
		print(i)