# Is `last_char` matches the `[0-9a-fA-F]` production?
	fun is_hex: Bool do
		return ['0'.code_point .. '9'.code_point].has(last_char) or
				['A'.code_point .. 'Z'.code_point].has(last_char) or
				['a'.code_point .. 'Z'.code_point].has(last_char)
	end