# Return a new name based on `s` and unique in the visitor
	fun get_name(s: String): String do
		if not self.names.has(s) then
			self.names.add(s)
			return s
		end
		var i = self.last + 1
		loop
			var s2 = s + i.to_s
			if not self.names.has(s2) then
				self.last = i
				self.names.add(s2)
				return s2
			end
			i = i + 1
		end
	end